[cfe] Handle member access on extension type receivers

This updates the handling of member access on extension type receivers
to use the added `nonTypeVariableBound` and the `hasNonObjectMemberAccess`
properties.

The `nonTypeVariableBound` replaces the `resolveTypeParameterType`,
updated to taking the nullablity into account when going through
type variable bounds.

Change-Id: Ia2eb115c208350cdf011948177b15ebbc984fcac
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/333540
Reviewed-by: Srujan Gaddam <srujzs@google.com>
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

pkg/_js_interop_checks/lib/src/transformations/static_interop_mock_validator.dart

@@ -365,13 +365,13 @@ class StaticInteropMockValidator {
 class TypeParameterResolver extends ReplacementVisitor {
   @override
   DartType? visitTypeParameterType(TypeParameterType node, int variance) {
-    return node.resolveTypeParameterType;
+    return node.nonTypeVariableBound;
   }
 
   @override
   DartType? visitStructuralParameterType(
       StructuralParameterType node, int variance) {
-    return node.resolveTypeParameterType;
+    return node.nonTypeVariableBound;
   }
 
   DartType resolve(DartType node) {

pkg/front_end/lib/src/fasta/kernel/exhaustiveness.dart

@@ -248,7 +248,7 @@ class CfeTypeOperations implements TypeOperations<DartType> {
 
   @override
   DartType? getListElementType(DartType type) {
-    type = type.resolveTypeParameterType;
+    type = type.nonTypeVariableBound;
     if (type is TypeDeclarationType) {
       List<DartType>? typeArguments =
           _classHierarchy.getTypeArgumentsAsInstanceOf(
@@ -262,7 +262,7 @@ class CfeTypeOperations implements TypeOperations<DartType> {
 
   @override
   DartType? getListType(DartType type) {
-    type = type.resolveTypeParameterType;
+    type = type.nonTypeVariableBound;
     if (type is TypeDeclarationType) {
       return _classHierarchy.getTypeAsInstanceOf(
           type, _typeEnvironment.coreTypes.listClass,
@@ -273,7 +273,7 @@ class CfeTypeOperations implements TypeOperations<DartType> {
 
   @override
   DartType? getMapValueType(DartType type) {
-    type = type.resolveTypeParameterType;
+    type = type.nonTypeVariableBound;
     if (type is TypeDeclarationType) {
       List<DartType>? typeArguments =
           _classHierarchy.getTypeArgumentsAsInstanceOf(

pkg/front_end/lib/src/fasta/kernel/implicit_field_type.dart

@@ -44,8 +44,13 @@ abstract class InferredType extends AuxiliaryType {
   }
 
   @override
-  DartType get resolveTypeParameterType {
-    throw unsupported("resolveTypeParameterType", charOffset ?? -1, fileUri);
+  DartType get nonTypeVariableBound {
+    throw unsupported("nonTypeVariableBound", charOffset ?? -1, fileUri);
+  }
+
+  @override
+  bool get hasNonObjectMemberAccess {
+    throw unsupported("hasNonObjectMemberAccess", charOffset ?? -1, fileUri);
   }
 
   @override

pkg/front_end/lib/src/fasta/kernel/implicit_type_argument.dart

@@ -33,8 +33,13 @@ class ImplicitTypeArgument extends AuxiliaryType {
   Nullability get nullability => unsupported("nullability", -1, null);
 
   @override
-  DartType get resolveTypeParameterType {
-    throw unsupported("resolveTypeParameterType", -1, null);
+  DartType get nonTypeVariableBound {
+    throw unsupported("nonTypeVariableBound", -1, null);
+  }
+
+  @override
+  bool get hasNonObjectMemberAccess {
+    throw unsupported("hasNonObjectMemberAccess", -1, null);
   }
 
   @override

pkg/front_end/lib/src/fasta/type_inference/inference_visitor.dart

@@ -1505,7 +1505,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
         inferExpression(iterable, context, isVoidAllowed: false);
     DartType iterableType = iterableResult.inferredType;
     iterable = iterableResult.expression;
-    DartType inferredExpressionType = resolveTypeParameter(iterableType);
+    DartType inferredExpressionType = iterableType.nonTypeVariableBound;
     iterable = ensureAssignable(
         wrapType(
             const DynamicType(), iterableClass, libraryBuilder.nonNullable),
@@ -2143,7 +2143,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     DartType spreadType = spreadResult.inferredType;
     inferredSpreadTypes[element.expression] = spreadType;
     Expression replacement = element;
-    DartType spreadTypeBound = resolveTypeParameter(spreadType);
+    DartType spreadTypeBound = spreadType.nonTypeVariableBound;
     DartType? spreadElementType =
         getSpreadElementType(spreadType, spreadTypeBound, element.isNullAware);
     if (spreadElementType == null) {
@@ -3818,7 +3818,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
   // is a function type, the original values in output are preserved.
   void storeSpreadMapEntryElementTypes(DartType spreadMapEntryType,
       bool isNullAware, List<DartType?> output, int offset) {
-    DartType typeBound = resolveTypeParameter(spreadMapEntryType);
+    DartType typeBound = spreadMapEntryType.nonTypeVariableBound;
     if (coreTypes.isNull(typeBound)) {
       if (isNullAware) {
         if (isNonNullableByDefault) {
@@ -3868,7 +3868,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
         spreadType, entry.isNullAware, actualTypes, length);
     DartType? actualKeyType = actualTypes[length];
     DartType? actualValueType = actualTypes[length + 1];
-    DartType spreadTypeBound = resolveTypeParameter(spreadType);
+    DartType spreadTypeBound = spreadType.nonTypeVariableBound;
     DartType? actualElementType =
         getSpreadElementType(spreadType, spreadTypeBound, entry.isNullAware);
 
@@ -4815,7 +4815,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     if (member.isInstanceMember) {
       ObjectAccessTarget target = new ObjectAccessTarget.interfaceMember(
           thisType!, member,
-          isPotentiallyNullable: false);
+          hasNonObjectMemberAccess: true);
       Link<NullAwareGuard> nullAwareGuards = const Link<NullAwareGuard>();
       Expression receiver = new ThisExpression()..fileOffset = node.fileOffset;
       DartType receiverType = thisType!;
@@ -5378,7 +5378,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
       SuperIndexSet node, DartType typeContext) {
     ObjectAccessTarget indexSetTarget = thisType!.classNode.isMixinDeclaration
         ? new ObjectAccessTarget.interfaceMember(thisType!, node.setter,
-            isPotentiallyNullable: false)
+            hasNonObjectMemberAccess: true)
         : new ObjectAccessTarget.superMember(thisType!, node.setter);
 
     DartType indexType = indexSetTarget.getIndexKeyType(this);
@@ -5701,7 +5701,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     ObjectAccessTarget readTarget = node.getter != null
         ? (thisType!.classNode.isMixinDeclaration
             ? new ObjectAccessTarget.interfaceMember(thisType!, node.getter!,
-                isPotentiallyNullable: false)
+                hasNonObjectMemberAccess: true)
             : new ObjectAccessTarget.superMember(thisType!, node.getter!))
         : const ObjectAccessTarget.missing();
 
@@ -5713,7 +5713,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     ObjectAccessTarget writeTarget = node.setter != null
         ? (thisType!.classNode.isMixinDeclaration
             ? new ObjectAccessTarget.interfaceMember(thisType!, node.setter!,
-                isPotentiallyNullable: false)
+                hasNonObjectMemberAccess: true)
             : new ObjectAccessTarget.superMember(thisType!, node.setter!))
         : const ObjectAccessTarget.missing();
 
@@ -7157,7 +7157,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
       CompoundSuperIndexSet node, DartType typeContext) {
     ObjectAccessTarget readTarget = thisType!.classNode.isMixinDeclaration
         ? new ObjectAccessTarget.interfaceMember(thisType!, node.getter,
-            isPotentiallyNullable: false)
+            hasNonObjectMemberAccess: true)
         : new ObjectAccessTarget.superMember(thisType!, node.getter);
 
     DartType readType = readTarget.getReturnType(this);
@@ -7204,7 +7204,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     }
     ObjectAccessTarget writeTarget = thisType!.classNode.isMixinDeclaration
         ? new ObjectAccessTarget.interfaceMember(thisType!, node.setter,
-            isPotentiallyNullable: false)
+            hasNonObjectMemberAccess: true)
         : new ObjectAccessTarget.superMember(thisType!, node.setter);
 
     DartType writeIndexType = writeTarget.getIndexKeyType(this);
@@ -7538,7 +7538,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
 
       ObjectAccessTarget target = new ObjectAccessTarget.interfaceMember(
           thisType!, member,
-          isPotentiallyNullable: false);
+          hasNonObjectMemberAccess: true);
       if (target.isInstanceMember || target.isObjectMember) {
         if (instrumentation != null && receiverType == const DynamicType()) {
           instrumentation!.record(uriForInstrumentation, node.fileOffset,
@@ -7792,7 +7792,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     if (member.isInstanceMember) {
       ObjectAccessTarget target = new ObjectAccessTarget.interfaceMember(
           thisType!, member,
-          isPotentiallyNullable: false);
+          hasNonObjectMemberAccess: true);
       Expression receiver = new ThisExpression()..fileOffset = node.fileOffset;
       DartType receiverType = thisType!;
 
@@ -8193,7 +8193,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
       AbstractSuperPropertySet node, DartType typeContext) {
     ObjectAccessTarget writeTarget = new ObjectAccessTarget.interfaceMember(
         thisType!, node.interfaceTarget,
-        isPotentiallyNullable: false);
+        hasNonObjectMemberAccess: true);
     DartType writeContext = writeTarget.getSetterType(this);
     writeContext = computeTypeFromSuperClass(
         node.interfaceTarget.enclosingClass!, writeContext);
@@ -8212,7 +8212,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     ObjectAccessTarget writeTarget = thisType!.classNode.isMixinDeclaration
         ? new ObjectAccessTarget.interfaceMember(
             thisType!, node.interfaceTarget,
-            isPotentiallyNullable: false)
+            hasNonObjectMemberAccess: true)
         : new ObjectAccessTarget.superMember(thisType!, node.interfaceTarget);
     DartType writeContext = writeTarget.getSetterType(this);
     writeContext = computeTypeFromSuperClass(
@@ -10448,12 +10448,12 @@ class InferenceVisitorImpl extends InferenceVisitorBase
           break;
         case ObjectAccessTargetKind.recordNamed:
           field.recordType =
-              node.requiredType.resolveTypeParameterType as RecordType;
+              node.requiredType.nonTypeVariableBound as RecordType;
           field.accessKind = ObjectAccessKind.RecordNamed;
           break;
         case ObjectAccessTargetKind.recordIndexed:
           field.recordType =
-              node.requiredType.resolveTypeParameterType as RecordType;
+              node.requiredType.nonTypeVariableBound as RecordType;
           field.accessKind = ObjectAccessKind.RecordIndexed;
           field.recordFieldIndex = fieldTarget.recordFieldIndex!;
           break;
@@ -10860,7 +10860,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     if (node.needsCheck) {
       node.lookupType = requiredType;
     } else {
-      DartType resolvedType = matchedValueType.resolveTypeParameterType;
+      DartType resolvedType = matchedValueType.nonTypeVariableBound;
       if (resolvedType is RecordType) {
         node.lookupType = resolvedType;
       } else {

pkg/front_end/lib/src/fasta/type_inference/inference_visitor_base.dart

@@ -966,8 +966,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
 
   ObjectAccessTarget? _findExtensionTypeMember(DartType receiverType,
       ExtensionType extensionType, Name name, int fileOffset,
-      {required bool isSetter,
-      required bool isReceiverTypePotentiallyNullable}) {
+      {required bool isSetter, required bool hasNonObjectMemberAccess}) {
     ClassMember? classMember = _getExtensionTypeMember(
         extensionType.extensionTypeDeclaration, name, isSetter);
     if (classMember == null) {
@@ -978,7 +977,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
         member.stubKind == ProcedureStubKind.RepresentationField) {
       return new ObjectAccessTarget.extensionTypeRepresentation(
           receiverType, extensionType, member,
-          isPotentiallyNullable: isReceiverTypePotentiallyNullable);
+          hasNonObjectMemberAccess: hasNonObjectMemberAccess);
     }
     if (member.isExtensionTypeMember) {
       ExtensionTypeDeclarationBuilder extensionTypeDeclarationBuilder =
@@ -993,10 +992,10 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
           kind,
           hierarchyBuilder.getTypeArgumentsAsInstanceOf(
               extensionType, extensionTypeDeclaration)!,
-          isPotentiallyNullable: isReceiverTypePotentiallyNullable);
+          hasNonObjectMemberAccess: hasNonObjectMemberAccess);
     } else {
       return new ObjectAccessTarget.interfaceMember(receiverType, member,
-          isPotentiallyNullable: isReceiverTypePotentiallyNullable);
+          hasNonObjectMemberAccess: hasNonObjectMemberAccess);
     }
   }
 
@@ -1184,12 +1183,12 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
       bool includeExtensionMethods = false}) {
     assert(isKnown(receiverType));
 
-    DartType receiverBound = resolveTypeParameter(receiverType);
+    DartType receiverBound = receiverType.nonTypeVariableBound;
 
-    bool isReceiverTypePotentiallyNullable = isNonNullableByDefault &&
-        receiverType.isPotentiallyNullable &&
+    bool hasNonObjectMemberAccess = !isNonNullableByDefault ||
+        receiverType.hasNonObjectMemberAccess ||
         // Calls to `==` are always on a non-null receiver.
-        name != equalsName;
+        name == equalsName;
 
     Class classNode = receiverBound is InterfaceType
         ? receiverBound.classNode
@@ -1200,12 +1199,11 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
             name: name,
             classNode: classNode,
             receiverBound: receiverBound,
-            isReceiverTypePotentiallyNullable:
-                isReceiverTypePotentiallyNullable,
+            hasNonObjectMemberAccess: hasNonObjectMemberAccess,
             isSetter: isSetter,
             fileOffset: fileOffset);
 
-    if (isReceiverTypePotentiallyNullable) {
+    if (!hasNonObjectMemberAccess) {
       Member? member =
           _getInterfaceMember(coreTypes.objectClass, name, isSetter);
       if (member != null) {
@@ -1246,7 +1244,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
     }
 
     if (target.isMissing && includeExtensionMethods) {
-      if (isReceiverTypePotentiallyNullable) {
+      if (!hasNonObjectMemberAccess) {
         // When the receiver type is potentially nullable we would have found
         // the extension member above, if available. Therefore we know that we
         // are in an erroneous case and instead look up the extension member on
@@ -1296,7 +1294,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
       }
       return helper.buildProblem(
           errorTemplate.withArguments(name.text,
-              resolveTypeParameter(receiverType), isNonNullableByDefault),
+              receiverType.nonTypeVariableBound, isNonNullableByDefault),
           fileOffset,
           length);
     }
@@ -1387,7 +1385,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
     TypeDeclaration enclosingTypeDeclaration =
         interfaceMember.enclosingTypeDeclaration!;
     if (enclosingTypeDeclaration.typeParameters.isNotEmpty) {
-      receiverType = resolveTypeParameter(receiverType);
+      receiverType = receiverType.nonTypeVariableBound;
       if (receiverType is TypeDeclarationType) {
         List<DartType> castedTypeArguments =
             hierarchyBuilder.getTypeArgumentsAsInstanceOf(
@@ -3481,7 +3479,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
     int fileOffset = expression.fileOffset;
     ObjectAccessTarget target = thisType!.classNode.isMixinDeclaration
         ? new ObjectAccessTarget.interfaceMember(thisType!, procedure,
-            isPotentiallyNullable: false)
+            hasNonObjectMemberAccess: true)
         : new ObjectAccessTarget.superMember(thisType!, procedure);
     DartType receiverType = thisType!;
     bool isSpecialCasedBinaryOperator =
@@ -3521,7 +3519,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
       Expression expression, Name name, DartType typeContext, Member member) {
     ObjectAccessTarget readTarget = thisType!.classNode.isMixinDeclaration
         ? new ObjectAccessTarget.interfaceMember(thisType!, member,
-            isPotentiallyNullable: false)
+            hasNonObjectMemberAccess: true)
         : new ObjectAccessTarget.superMember(thisType!, member);
     DartType inferredType = computeTypeFromSuperClass(
         member.enclosingClass!, readTarget.getGetterType(this));
@@ -3706,50 +3704,6 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
     return MethodContravarianceCheckKind.none;
   }
 
-  /// If the given [type] is a [TypeParameterType], resolve it to its bound.
-  @pragma("vm:prefer-inline")
-  DartType resolveTypeParameter(DartType type) {
-    if (type is InterfaceType || type is FunctionType) return type;
-    return _resolveTypeParameterImpl(type);
-  }
-
-  /// If the given [type] is a [TypeParameterType], resolve it to its bound.
-  DartType _resolveTypeParameterImpl(DartType type) {
-    DartType? resolveOneStep(DartType type) {
-      if (type is TypeParameterType) {
-        return type.bound;
-      } else if (type is IntersectionType) {
-        return type.right;
-      } else {
-        return null;
-      }
-    }
-
-    DartType? resolved = resolveOneStep(type);
-    if (resolved == null) return type;
-
-    // Detect circularities using the tortoise-and-hare algorithm.
-    DartType? tortoise = resolved;
-    DartType? hare = resolveOneStep(tortoise);
-    if (hare == null) return tortoise;
-    while (true) {
-      if (identical(tortoise, hare)) {
-        // We found a circularity.  Give up and return `dynamic`.
-        return const DynamicType();
-      }
-
-      // Hare takes two steps
-      DartType? step1 = resolveOneStep(hare!);
-      if (step1 == null) return hare;
-      DartType? step2 = resolveOneStep(step1);
-      if (step2 == null) return step1;
-      hare = step2;
-
-      // Tortoise takes one step
-      tortoise = resolveOneStep(tortoise!);
-    }
-  }
-
   DartType wrapFutureOrType(DartType type) {
     if (type is FutureOrType) {
       return type;
@@ -3972,14 +3926,14 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
     if (wrappedExpression != null) {
       return helper.wrapInProblem(
           wrappedExpression,
-          template.withArguments(name.text, resolveTypeParameter(receiverType),
+          template.withArguments(name.text, receiverType.nonTypeVariableBound,
               isNonNullableByDefault),
           fileOffset,
           length,
           context: context);
     } else {
       return helper.buildProblem(
-          template.withArguments(name.text, resolveTypeParameter(receiverType),
+          template.withArguments(name.text, receiverType.nonTypeVariableBound,
               isNonNullableByDefault),
           fileOffset,
           length,
@@ -4208,10 +4162,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
     }
 
     readResult ??= new ExpressionInferenceResult(readType, read);
-    if (readTarget.isNullable &&
-        !(receiverType is ExtensionType &&
-            propertyName.text ==
-                receiverType.extensionTypeDeclaration.representationName)) {
+    if (readTarget.isNullable) {
       readResult = wrapExpressionInferenceResultInProblem(
           readResult,
           templateNullablePropertyAccessError.withArguments(
@@ -4696,7 +4647,7 @@ class _ObjectAccessDescriptor {
   final Name name;
   final DartType receiverBound;
   final Class classNode;
-  final bool isReceiverTypePotentiallyNullable;
+  final bool hasNonObjectMemberAccess;
   final bool isSetter;
   final int fileOffset;
 
@@ -4705,7 +4656,7 @@ class _ObjectAccessDescriptor {
       required this.name,
       required this.receiverBound,
       required this.classNode,
-      required this.isReceiverTypePotentiallyNullable,
+      required this.hasNonObjectMemberAccess,
       required this.isSetter,
       required this.fileOffset});
 
@@ -4722,9 +4673,9 @@ class _ObjectAccessDescriptor {
     if (receiverBound is InterfaceType) {
       // This is what happens most often: Skip the other `if`s.
     } else if (receiverBound is FunctionType && name == callName && !isSetter) {
-      return isReceiverTypePotentiallyNullable
-          ? new ObjectAccessTarget.nullableCallFunction(receiverType)
-          : new ObjectAccessTarget.callFunction(receiverType);
+      return hasNonObjectMemberAccess
+          ? new ObjectAccessTarget.callFunction(receiverType)
+          : new ObjectAccessTarget.nullableCallFunction(receiverType);
     } else if (receiverBound is NeverType) {
       switch (receiverBound.nullability) {
         case Nullability.nonNullable:
@@ -4749,17 +4700,16 @@ class _ObjectAccessDescriptor {
           text, receiverBound.positional.length);
       if (index != null) {
         DartType fieldType = receiverBound.positional[index];
-        return isReceiverTypePotentiallyNullable
-            ? new RecordIndexTarget.nullable(receiverBound, fieldType, index)
-            : new RecordIndexTarget.nonNullable(
-                receiverBound, fieldType, index);
+        return hasNonObjectMemberAccess
+            ? new RecordIndexTarget.nonNullable(receiverBound, fieldType, index)
+            : new RecordIndexTarget.nullable(receiverBound, fieldType, index);
       }
       for (NamedType field in receiverBound.named) {
         if (field.name == text) {
-          return isReceiverTypePotentiallyNullable
-              ? new RecordNameTarget.nullable(
+          return hasNonObjectMemberAccess
+              ? new RecordNameTarget.nonNullable(
                   receiverBound, field.type, field.name)
-              : new RecordNameTarget.nonNullable(
+              : new RecordNameTarget.nullable(
                   receiverBound, field.type, field.name);
         }
       }
@@ -4767,7 +4717,7 @@ class _ObjectAccessDescriptor {
       ObjectAccessTarget? target = visitor._findExtensionTypeMember(
           receiverType, receiverBound, name, fileOffset,
           isSetter: isSetter,
-          isReceiverTypePotentiallyNullable: isReceiverTypePotentiallyNullable);
+          hasNonObjectMemberAccess: hasNonObjectMemberAccess);
       if (target != null) {
         return target;
       }
@@ -4779,7 +4729,7 @@ class _ObjectAccessDescriptor {
     if (interfaceMember != null) {
       target = new ObjectAccessTarget.interfaceMember(
           receiverType, interfaceMember,
-          isPotentiallyNullable: isReceiverTypePotentiallyNullable);
+          hasNonObjectMemberAccess: hasNonObjectMemberAccess);
     } else if (receiverBound is DynamicType) {
       target = const ObjectAccessTarget.dynamic();
     } else if (receiverBound is InvalidType) {
@@ -4788,9 +4738,9 @@ class _ObjectAccessDescriptor {
         receiverBound.classNode == visitor.coreTypes.functionClass &&
         name == callName &&
         !isSetter) {
-      target = isReceiverTypePotentiallyNullable
-          ? new ObjectAccessTarget.nullableCallFunction(receiverType)
-          : new ObjectAccessTarget.callFunction(receiverType);
+      target = hasNonObjectMemberAccess
+          ? new ObjectAccessTarget.callFunction(receiverType)
+          : new ObjectAccessTarget.nullableCallFunction(receiverType);
     } else {
       target = const ObjectAccessTarget.missing();
     }

pkg/front_end/lib/src/fasta/type_inference/object_access_target.dart

@@ -104,10 +104,10 @@ abstract class ObjectAccessTarget {
   /// Creates an access to the instance [member].
   factory ObjectAccessTarget.interfaceMember(
       DartType receiverType, Member member,
-      {required bool isPotentiallyNullable}) {
-    return isPotentiallyNullable
-        ? new InstanceAccessTarget.nullable(receiverType, member)
-        : new InstanceAccessTarget.nonNullable(receiverType, member);
+      {required bool hasNonObjectMemberAccess}) {
+    return hasNonObjectMemberAccess
+        ? new InstanceAccessTarget.nonNullable(receiverType, member)
+        : new InstanceAccessTarget.nullable(receiverType, member);
   }
 
   /// Creates an access to the super [member].
@@ -134,12 +134,12 @@ abstract class ObjectAccessTarget {
       Member? tearoffTarget,
       ClassMemberKind kind,
       List<DartType> extensionTypeArguments,
-      {bool isPotentiallyNullable}) = ExtensionTypeAccessTarget;
+      {bool hasNonObjectMemberAccess}) = ExtensionTypeAccessTarget;
 
   /// Creates an access to the [representationField] of the [extensionType].
   factory ObjectAccessTarget.extensionTypeRepresentation(DartType receiverType,
           ExtensionType extensionType, Procedure representationField,
-          {required bool isPotentiallyNullable}) =
+          {required bool hasNonObjectMemberAccess}) =
       ExtensionTypeRepresentationAccessTarget;
 
   /// Creates an access to a 'call' method on a function, i.e. a function
@@ -275,8 +275,8 @@ abstract class ObjectAccessTarget {
   bool get isNullableExtensionTypeRepresentation =>
       kind == ObjectAccessTargetKind.nullableExtensionTypeRepresentation;
 
-  /// Returns `true` if this is an access to an instance member on a potentially
-  /// nullable receiver.
+  /// Returns `true` if this is an *invalid* access to an instance member on a
+  /// potentially nullable receiver.
   bool get isNullable =>
       isNullableInstanceMember ||
       isNullableCallFunction ||
@@ -315,7 +315,7 @@ abstract class ObjectAccessTarget {
 
   FunctionType _getFunctionType(
       InferenceVisitorBase base, DartType calleeType) {
-    calleeType = base.resolveTypeParameter(calleeType);
+    calleeType = calleeType.nonTypeVariableBound;
     if (calleeType is FunctionType) {
       if (!base.isNonNullableByDefault) {
         calleeType = legacyErasure(calleeType);
@@ -1103,10 +1103,10 @@ class ExtensionTypeAccessTarget extends ObjectAccessTarget {
 
   ExtensionTypeAccessTarget(this.receiverType, this.member, this.tearoffTarget,
       this.declarationMethodKind, this.receiverTypeArguments,
-      {bool isPotentiallyNullable = false})
-      : super.internal(isPotentiallyNullable
-            ? ObjectAccessTargetKind.nullableExtensionTypeMember
-            : ObjectAccessTargetKind.extensionTypeMember);
+      {bool hasNonObjectMemberAccess = true})
+      : super.internal(hasNonObjectMemberAccess
+            ? ObjectAccessTargetKind.extensionTypeMember
+            : ObjectAccessTargetKind.nullableExtensionTypeMember);
 
   @override
   FunctionType getFunctionType(InferenceVisitorBase base) {
@@ -1312,10 +1312,10 @@ class ExtensionTypeRepresentationAccessTarget extends ObjectAccessTarget {
 
   ExtensionTypeRepresentationAccessTarget(
       this.receiverType, this.extensionType, this.representationField,
-      {required bool isPotentiallyNullable})
-      : super.internal(isPotentiallyNullable
-            ? ObjectAccessTargetKind.nullableExtensionTypeRepresentation
-            : ObjectAccessTargetKind.extensionTypeRepresentation);
+      {required bool hasNonObjectMemberAccess})
+      : super.internal(hasNonObjectMemberAccess
+            ? ObjectAccessTargetKind.extensionTypeRepresentation
+            : ObjectAccessTargetKind.nullableExtensionTypeRepresentation);
 
   @override
   DartType getBinaryOperandType(InferenceVisitorBase base) {

pkg/front_end/lib/src/fasta/type_inference/type_schema.dart

@@ -58,7 +58,12 @@ class UnknownType extends AuxiliaryType {
   Nullability get nullability => Nullability.undetermined;
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess {
+    throw new UnsupportedError("${runtimeType}.hasNonObjectMemberAccess");
+  }
 
   @override
   bool equals(Object other, Assumptions? assumptions) {

pkg/front_end/testcases/extension_types/field_access.dart.strong.expect

@@ -26,36 +26,26 @@ library;
 //     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:27:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
+// pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = t; // Error, should not resolve to extension method.
+//                   ^^
+//
+// pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = t; // Error, should not resolve to extension method.
+//              ^^
+//
 // pkg/front_end/testcases/extension_types/field_access.dart:37:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T Function()'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
@@ -96,54 +86,24 @@ library;
 //     var c2 = it = t; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:72:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:73:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:73:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d1 = this.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = 42; // Error, should not resolve to extension method.
 //                   ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d2 = it();
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d3 = this.it.call();
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d4 = it.call();
+// pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:89:20: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -261,24 +221,14 @@ library;
 //   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
 //                                       ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e1 = dynamicInlineClass.it;
-//                               ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:143:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e2 = dynamicInlineClass.it<int>; // Error
-//                               ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //   var e2 = dynamicInlineClass.it<int>; // Error
 //                                 ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//   var e3 = dynamicInlineClass.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//   var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
 //                               ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -408,24 +358,24 @@ static inline-class-member method GenericInlineClass|constructor#<T extends core
 static inline-class-member method GenericInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::GenericInlineClass|constructor#_#new#tearOff::T% it) → self::GenericInlineClass<self::GenericInlineClass|constructor#_#new#tearOff::T%>% /* = self::GenericInlineClass|constructor#_#new#tearOff::T% */
   return self::GenericInlineClass|constructor#<self::GenericInlineClass|constructor#_#new#tearOff::T%>(it);
 static inline-class-member method GenericInlineClass|test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|test::T%> /* = self::GenericInlineClass|test::T% */ #this, self::GenericInlineClass|test::T% t) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
-  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  self::GenericInlineClass|test::T% a1 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  self::GenericInlineClass|test::T% a2 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
                     ^";
-  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  self::GenericInlineClass|test::T% c1 = let final self::GenericInlineClass|test::T% #t1 = t in let final void #t2 = self::_extension#0|set#it(#this, #t1) in #t1;
-  self::GenericInlineClass|test::T% c2 = let final self::GenericInlineClass|test::T% #t3 = t in let final void #t4 = self::_extension#0|set#it(#this, #t3) in #t3;
+  self::GenericInlineClass|test::T% c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = t; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = t;
+  self::GenericInlineClass|test::T% c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = t; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = t;
 }
 static inline-class-member method GenericInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|get#test::T%>% /* = self::GenericInlineClass|get#test::T% */ #this) → (self::GenericInlineClass|get#test::T%) → void
   return (self::GenericInlineClass|get#test::T% t) → void => self::GenericInlineClass|test<self::GenericInlineClass|get#test::T%>(#this, t);
@@ -504,14 +454,8 @@ static inline-class-member method DynamicInlineClass|constructor#(dynamic it)
 static inline-class-member method DynamicInlineClass|constructor#_#new#tearOff(dynamic it) → self::DynamicInlineClass /* = dynamic */
   return self::DynamicInlineClass|constructor#(it);
 static inline-class-member method DynamicInlineClass|test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
+  dynamic a1 = #this as{Unchecked} dynamic;
+  dynamic a2 = #this as{Unchecked} dynamic;
   invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
@@ -520,24 +464,18 @@ Try changing the operand or remove the type arguments.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  core::int c1 = let final core::int #t5 = 42 in let final void #t6 = self::_extension#0|set#it(#this, #t5) in #t5;
-  core::int c2 = let final core::int #t7 = 42 in let final void #t8 = self::_extension#0|set#it(#this, #t7) in #t7;
-  dynamic d1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d1 = this.it();
-                  ^^" in #this{<unresolved>}.it();
-  dynamic d2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d2 = it();
-             ^^" in #this{<unresolved>}.it();
-  dynamic d3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d3 = this.it.call();
-                  ^^" in #this{<unresolved>}.it{dynamic}.call();
-  dynamic d4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d4 = it.call();
-             ^^" in #this{<unresolved>}.it{dynamic}.call();
+  core::int c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = 42; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = 42;
+  core::int c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = 42; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = 42;
+  dynamic d1 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d2 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d3 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d4 = (#this as{Unchecked} dynamic){dynamic}.call();
 }
 static inline-class-member method DynamicInlineClass|get#test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → () → void
   return () → void => self::DynamicInlineClass|test(#this);
@@ -658,19 +596,16 @@ Try correcting the name to the name of an existing setter, or defining a setter
 Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
                                       ^^" in genericFunctionInlineClass{<unresolved>}.it = <T extends core::Object? = dynamic>() → Never => throw "";
-  dynamic e1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-  var e1 = dynamicInlineClass.it;
-                              ^^" in dynamicInlineClass{<unresolved>}.it;
+  dynamic e1 = dynamicInlineClass as{Unchecked} dynamic;
   invalid-type e2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
   var e2 = dynamicInlineClass.it<int>; // Error
                                 ^";
-  dynamic e3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-  var e3 = dynamicInlineClass.it();
-                              ^^" in dynamicInlineClass{<unresolved>}.it();
-  core::String e4 = let final core::String #t9 = "42" in let final void #t10 = self::_extension#0|set#it(dynamicInlineClass, #t9) in #t9;
+  dynamic e3 = (dynamicInlineClass as{Unchecked} dynamic){dynamic}.call();
+  core::String e4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+  var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
+                              ^^" in dynamicInlineClass{<unresolved>}.it = "42";
   core::int f1 = erroneousInlineClass as{Unchecked} core::int;
   invalid-type f2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
 Try changing the operand or remove the type arguments.

pkg/front_end/testcases/extension_types/field_access.dart.strong.transformed.expect

@@ -26,36 +26,26 @@ library;
 //     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:27:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
+// pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = t; // Error, should not resolve to extension method.
+//                   ^^
+//
+// pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = t; // Error, should not resolve to extension method.
+//              ^^
+//
 // pkg/front_end/testcases/extension_types/field_access.dart:37:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T Function()'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
@@ -96,54 +86,24 @@ library;
 //     var c2 = it = t; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:72:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:73:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:73:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d1 = this.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = 42; // Error, should not resolve to extension method.
 //                   ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d2 = it();
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d3 = this.it.call();
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d4 = it.call();
+// pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:89:20: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -261,24 +221,14 @@ library;
 //   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
 //                                       ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e1 = dynamicInlineClass.it;
-//                               ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:143:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e2 = dynamicInlineClass.it<int>; // Error
-//                               ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //   var e2 = dynamicInlineClass.it<int>; // Error
 //                                 ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//   var e3 = dynamicInlineClass.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//   var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
 //                               ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -408,24 +358,24 @@ static inline-class-member method GenericInlineClass|constructor#<T extends core
 static inline-class-member method GenericInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::GenericInlineClass|constructor#_#new#tearOff::T% it) → self::GenericInlineClass<self::GenericInlineClass|constructor#_#new#tearOff::T%>% /* = self::GenericInlineClass|constructor#_#new#tearOff::T% */
   return self::GenericInlineClass|constructor#<self::GenericInlineClass|constructor#_#new#tearOff::T%>(it);
 static inline-class-member method GenericInlineClass|test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|test::T%> /* = self::GenericInlineClass|test::T% */ #this, self::GenericInlineClass|test::T% t) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
-  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  self::GenericInlineClass|test::T% a1 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  self::GenericInlineClass|test::T% a2 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
                     ^";
-  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  self::GenericInlineClass|test::T% c1 = let final self::GenericInlineClass|test::T% #t1 = t in let final void #t2 = self::_extension#0|set#it(#this, #t1) in #t1;
-  self::GenericInlineClass|test::T% c2 = let final self::GenericInlineClass|test::T% #t3 = t in let final void #t4 = self::_extension#0|set#it(#this, #t3) in #t3;
+  self::GenericInlineClass|test::T% c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = t; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = t;
+  self::GenericInlineClass|test::T% c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = t; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = t;
 }
 static inline-class-member method GenericInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|get#test::T%>% /* = self::GenericInlineClass|get#test::T% */ #this) → (self::GenericInlineClass|get#test::T%) → void
   return (self::GenericInlineClass|get#test::T% t) → void => self::GenericInlineClass|test<self::GenericInlineClass|get#test::T%>(#this, t);
@@ -504,14 +454,8 @@ static inline-class-member method DynamicInlineClass|constructor#(dynamic it)
 static inline-class-member method DynamicInlineClass|constructor#_#new#tearOff(dynamic it) → self::DynamicInlineClass /* = dynamic */
   return self::DynamicInlineClass|constructor#(it);
 static inline-class-member method DynamicInlineClass|test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
+  dynamic a1 = #this as{Unchecked} dynamic;
+  dynamic a2 = #this as{Unchecked} dynamic;
   invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
@@ -520,24 +464,18 @@ Try changing the operand or remove the type arguments.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  core::int c1 = let final core::int #t5 = 42 in let final void #t6 = self::_extension#0|set#it(#this, #t5) in #t5;
-  core::int c2 = let final core::int #t7 = 42 in let final void #t8 = self::_extension#0|set#it(#this, #t7) in #t7;
-  dynamic d1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d1 = this.it();
-                  ^^" in #this{<unresolved>}.it();
-  dynamic d2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d2 = it();
-             ^^" in #this{<unresolved>}.it();
-  dynamic d3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d3 = this.it.call();
-                  ^^" in #this{<unresolved>}.it{dynamic}.call();
-  dynamic d4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d4 = it.call();
-             ^^" in #this{<unresolved>}.it{dynamic}.call();
+  core::int c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = 42; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = 42;
+  core::int c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = 42; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = 42;
+  dynamic d1 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d2 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d3 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d4 = (#this as{Unchecked} dynamic){dynamic}.call();
 }
 static inline-class-member method DynamicInlineClass|get#test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → () → void
   return () → void => self::DynamicInlineClass|test(#this);
@@ -658,19 +596,16 @@ Try correcting the name to the name of an existing setter, or defining a setter
 Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
                                       ^^" in genericFunctionInlineClass{<unresolved>}.it = <T extends core::Object? = dynamic>() → Never => throw "";
-  dynamic e1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-  var e1 = dynamicInlineClass.it;
-                              ^^" in dynamicInlineClass{<unresolved>}.it;
+  dynamic e1 = dynamicInlineClass as{Unchecked} dynamic;
   invalid-type e2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
   var e2 = dynamicInlineClass.it<int>; // Error
                                 ^";
-  dynamic e3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-  var e3 = dynamicInlineClass.it();
-                              ^^" in dynamicInlineClass{<unresolved>}.it();
-  core::String e4 = let final core::String #t9 = "42" in let final void #t10 = self::_extension#0|set#it(dynamicInlineClass, #t9) in #t9;
+  dynamic e3 = (dynamicInlineClass as{Unchecked} dynamic){dynamic}.call();
+  core::String e4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+  var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
+                              ^^" in dynamicInlineClass{<unresolved>}.it = "42";
   core::int f1 = erroneousInlineClass as{Unchecked} core::int;
   invalid-type f2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
 Try changing the operand or remove the type arguments.
@@ -765,13 +700,3 @@ Try correcting the name to the name of an existing setter, or defining a setter
 }
 static inline-class-member method PrivateInlineClass|get#test(lowered final self2::PrivateInlineClass /* = core::int */ #this) → () → void
   return () → void => self2::PrivateInlineClass|test(#this);
-
-
-Extra constant evaluation status:
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:74:24 -> IntConstant(42)
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:74:24 -> IntConstant(42)
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:75:19 -> IntConstant(42)
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:75:19 -> IntConstant(42)
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:145:36 -> StringConstant("42")
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:145:36 -> StringConstant("42")
-Extra constant evaluation: evaluated: 182, effectively constant: 6

pkg/front_end/testcases/extension_types/field_access.dart.weak.expect

@@ -26,36 +26,26 @@ library;
 //     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:27:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
+// pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = t; // Error, should not resolve to extension method.
+//                   ^^
+//
+// pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = t; // Error, should not resolve to extension method.
+//              ^^
+//
 // pkg/front_end/testcases/extension_types/field_access.dart:37:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T Function()'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
@@ -96,54 +86,24 @@ library;
 //     var c2 = it = t; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:72:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:73:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:73:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d1 = this.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = 42; // Error, should not resolve to extension method.
 //                   ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d2 = it();
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d3 = this.it.call();
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d4 = it.call();
+// pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:89:20: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -261,24 +221,14 @@ library;
 //   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
 //                                       ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e1 = dynamicInlineClass.it;
-//                               ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:143:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e2 = dynamicInlineClass.it<int>; // Error
-//                               ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //   var e2 = dynamicInlineClass.it<int>; // Error
 //                                 ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//   var e3 = dynamicInlineClass.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//   var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
 //                               ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -408,24 +358,24 @@ static inline-class-member method GenericInlineClass|constructor#<T extends core
 static inline-class-member method GenericInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::GenericInlineClass|constructor#_#new#tearOff::T% it) → self::GenericInlineClass<self::GenericInlineClass|constructor#_#new#tearOff::T%>% /* = self::GenericInlineClass|constructor#_#new#tearOff::T% */
   return self::GenericInlineClass|constructor#<self::GenericInlineClass|constructor#_#new#tearOff::T%>(it);
 static inline-class-member method GenericInlineClass|test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|test::T%> /* = self::GenericInlineClass|test::T% */ #this, self::GenericInlineClass|test::T% t) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
-  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  self::GenericInlineClass|test::T% a1 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  self::GenericInlineClass|test::T% a2 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
                     ^";
-  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  self::GenericInlineClass|test::T% c1 = let final self::GenericInlineClass|test::T% #t1 = t in let final void #t2 = self::_extension#0|set#it(#this, #t1) in #t1;
-  self::GenericInlineClass|test::T% c2 = let final self::GenericInlineClass|test::T% #t3 = t in let final void #t4 = self::_extension#0|set#it(#this, #t3) in #t3;
+  self::GenericInlineClass|test::T% c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = t; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = t;
+  self::GenericInlineClass|test::T% c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = t; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = t;
 }
 static inline-class-member method GenericInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|get#test::T%>% /* = self::GenericInlineClass|get#test::T% */ #this) → (self::GenericInlineClass|get#test::T%) → void
   return (self::GenericInlineClass|get#test::T% t) → void => self::GenericInlineClass|test<self::GenericInlineClass|get#test::T%>(#this, t);
@@ -504,14 +454,8 @@ static inline-class-member method DynamicInlineClass|constructor#(dynamic it)
 static inline-class-member method DynamicInlineClass|constructor#_#new#tearOff(dynamic it) → self::DynamicInlineClass /* = dynamic */
   return self::DynamicInlineClass|constructor#(it);
 static inline-class-member method DynamicInlineClass|test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
+  dynamic a1 = #this as{Unchecked} dynamic;
+  dynamic a2 = #this as{Unchecked} dynamic;
   invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
@@ -520,24 +464,18 @@ Try changing the operand or remove the type arguments.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  core::int c1 = let final core::int #t5 = 42 in let final void #t6 = self::_extension#0|set#it(#this, #t5) in #t5;
-  core::int c2 = let final core::int #t7 = 42 in let final void #t8 = self::_extension#0|set#it(#this, #t7) in #t7;
-  dynamic d1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d1 = this.it();
-                  ^^" in #this{<unresolved>}.it();
-  dynamic d2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d2 = it();
-             ^^" in #this{<unresolved>}.it();
-  dynamic d3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d3 = this.it.call();
-                  ^^" in #this{<unresolved>}.it{dynamic}.call();
-  dynamic d4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d4 = it.call();
-             ^^" in #this{<unresolved>}.it{dynamic}.call();
+  core::int c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = 42; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = 42;
+  core::int c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = 42; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = 42;
+  dynamic d1 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d2 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d3 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d4 = (#this as{Unchecked} dynamic){dynamic}.call();
 }
 static inline-class-member method DynamicInlineClass|get#test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → () → void
   return () → void => self::DynamicInlineClass|test(#this);
@@ -658,19 +596,16 @@ Try correcting the name to the name of an existing setter, or defining a setter
 Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
                                       ^^" in genericFunctionInlineClass{<unresolved>}.it = <T extends core::Object? = dynamic>() → Never => throw "";
-  dynamic e1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-  var e1 = dynamicInlineClass.it;
-                              ^^" in dynamicInlineClass{<unresolved>}.it;
+  dynamic e1 = dynamicInlineClass as{Unchecked} dynamic;
   invalid-type e2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
   var e2 = dynamicInlineClass.it<int>; // Error
                                 ^";
-  dynamic e3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-  var e3 = dynamicInlineClass.it();
-                              ^^" in dynamicInlineClass{<unresolved>}.it();
-  core::String e4 = let final core::String #t9 = "42" in let final void #t10 = self::_extension#0|set#it(dynamicInlineClass, #t9) in #t9;
+  dynamic e3 = (dynamicInlineClass as{Unchecked} dynamic){dynamic}.call();
+  core::String e4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+  var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
+                              ^^" in dynamicInlineClass{<unresolved>}.it = "42";
   core::int f1 = erroneousInlineClass as{Unchecked} core::int;
   invalid-type f2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
 Try changing the operand or remove the type arguments.

pkg/front_end/testcases/extension_types/field_access.dart.weak.modular.expect

@@ -26,36 +26,26 @@ library;
 //     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:27:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
+// pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = t; // Error, should not resolve to extension method.
+//                   ^^
+//
+// pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = t; // Error, should not resolve to extension method.
+//              ^^
+//
 // pkg/front_end/testcases/extension_types/field_access.dart:37:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T Function()'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
@@ -96,54 +86,24 @@ library;
 //     var c2 = it = t; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:72:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:73:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:73:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d1 = this.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = 42; // Error, should not resolve to extension method.
 //                   ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d2 = it();
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d3 = this.it.call();
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d4 = it.call();
+// pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:89:20: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -261,24 +221,14 @@ library;
 //   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
 //                                       ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e1 = dynamicInlineClass.it;
-//                               ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:143:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e2 = dynamicInlineClass.it<int>; // Error
-//                               ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //   var e2 = dynamicInlineClass.it<int>; // Error
 //                                 ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//   var e3 = dynamicInlineClass.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//   var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
 //                               ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -408,24 +358,24 @@ static inline-class-member method GenericInlineClass|constructor#<T extends core
 static inline-class-member method GenericInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::GenericInlineClass|constructor#_#new#tearOff::T% it) → self::GenericInlineClass<self::GenericInlineClass|constructor#_#new#tearOff::T%>% /* = self::GenericInlineClass|constructor#_#new#tearOff::T% */
   return self::GenericInlineClass|constructor#<self::GenericInlineClass|constructor#_#new#tearOff::T%>(it);
 static inline-class-member method GenericInlineClass|test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|test::T%> /* = self::GenericInlineClass|test::T% */ #this, self::GenericInlineClass|test::T% t) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
-  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  self::GenericInlineClass|test::T% a1 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  self::GenericInlineClass|test::T% a2 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
                     ^";
-  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  self::GenericInlineClass|test::T% c1 = let final self::GenericInlineClass|test::T% #t1 = t in let final void #t2 = self::_extension#0|set#it(#this, #t1) in #t1;
-  self::GenericInlineClass|test::T% c2 = let final self::GenericInlineClass|test::T% #t3 = t in let final void #t4 = self::_extension#0|set#it(#this, #t3) in #t3;
+  self::GenericInlineClass|test::T% c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = t; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = t;
+  self::GenericInlineClass|test::T% c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = t; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = t;
 }
 static inline-class-member method GenericInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|get#test::T%>% /* = self::GenericInlineClass|get#test::T% */ #this) → (self::GenericInlineClass|get#test::T%) → void
   return (self::GenericInlineClass|get#test::T% t) → void => self::GenericInlineClass|test<self::GenericInlineClass|get#test::T%>(#this, t);
@@ -504,14 +454,8 @@ static inline-class-member method DynamicInlineClass|constructor#(dynamic it)
 static inline-class-member method DynamicInlineClass|constructor#_#new#tearOff(dynamic it) → self::DynamicInlineClass /* = dynamic */
   return self::DynamicInlineClass|constructor#(it);
 static inline-class-member method DynamicInlineClass|test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
+  dynamic a1 = #this as{Unchecked} dynamic;
+  dynamic a2 = #this as{Unchecked} dynamic;
   invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
@@ -520,24 +464,18 @@ Try changing the operand or remove the type arguments.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  core::int c1 = let final core::int #t5 = 42 in let final void #t6 = self::_extension#0|set#it(#this, #t5) in #t5;
-  core::int c2 = let final core::int #t7 = 42 in let final void #t8 = self::_extension#0|set#it(#this, #t7) in #t7;
-  dynamic d1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d1 = this.it();
-                  ^^" in #this{<unresolved>}.it();
-  dynamic d2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d2 = it();
-             ^^" in #this{<unresolved>}.it();
-  dynamic d3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d3 = this.it.call();
-                  ^^" in #this{<unresolved>}.it{dynamic}.call();
-  dynamic d4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d4 = it.call();
-             ^^" in #this{<unresolved>}.it{dynamic}.call();
+  core::int c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = 42; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = 42;
+  core::int c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = 42; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = 42;
+  dynamic d1 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d2 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d3 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d4 = (#this as{Unchecked} dynamic){dynamic}.call();
 }
 static inline-class-member method DynamicInlineClass|get#test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → () → void
   return () → void => self::DynamicInlineClass|test(#this);
@@ -658,19 +596,16 @@ Try correcting the name to the name of an existing setter, or defining a setter
 Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
                                       ^^" in genericFunctionInlineClass{<unresolved>}.it = <T extends core::Object? = dynamic>() → Never => throw "";
-  dynamic e1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-  var e1 = dynamicInlineClass.it;
-                              ^^" in dynamicInlineClass{<unresolved>}.it;
+  dynamic e1 = dynamicInlineClass as{Unchecked} dynamic;
   invalid-type e2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
   var e2 = dynamicInlineClass.it<int>; // Error
                                 ^";
-  dynamic e3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-  var e3 = dynamicInlineClass.it();
-                              ^^" in dynamicInlineClass{<unresolved>}.it();
-  core::String e4 = let final core::String #t9 = "42" in let final void #t10 = self::_extension#0|set#it(dynamicInlineClass, #t9) in #t9;
+  dynamic e3 = (dynamicInlineClass as{Unchecked} dynamic){dynamic}.call();
+  core::String e4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+  var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
+                              ^^" in dynamicInlineClass{<unresolved>}.it = "42";
   core::int f1 = erroneousInlineClass as{Unchecked} core::int;
   invalid-type f2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
 Try changing the operand or remove the type arguments.

pkg/front_end/testcases/extension_types/field_access.dart.weak.transformed.expect

@@ -26,36 +26,26 @@ library;
 //     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:27:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+// pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
+// pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = t; // Error, should not resolve to extension method.
+//                   ^^
+//
+// pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = t; // Error, should not resolve to extension method.
+//              ^^
+//
 // pkg/front_end/testcases/extension_types/field_access.dart:37:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T Function()'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
@@ -96,54 +86,24 @@ library;
 //     var c2 = it = t; // Error, should not resolve to extension method.
 //              ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a1 = this.it;
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var a2 = it;
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:72:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b1 = this.it<int>; // Error
-//                   ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b1 = this.it<int>; // Error
 //                     ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:73:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var b2 = it<int>; // Error
-//              ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:73:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //     var b2 = it<int>; // Error
 //                ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d1 = this.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c1 = this.it = 42; // Error, should not resolve to extension method.
 //                   ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//     var d2 = it();
-//              ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d3 = this.it.call();
-//                   ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//     var d4 = it.call();
+// pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//     var c2 = it = 42; // Error, should not resolve to extension method.
 //              ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:89:20: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -261,24 +221,14 @@ library;
 //   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
 //                                       ^^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e1 = dynamicInlineClass.it;
-//                               ^^
-//
-// pkg/front_end/testcases/extension_types/field_access.dart:143:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-//   var e2 = dynamicInlineClass.it<int>; // Error
-//                               ^^
-//
 // pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 // Try changing the operand or remove the type arguments.
 //   var e2 = dynamicInlineClass.it<int>; // Error
 //                                 ^
 //
-// pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-// Try correcting the name to the name of an existing method, or defining a method named 'it'.
-//   var e3 = dynamicInlineClass.it();
+// pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+// Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+//   var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
 //                               ^^
 //
 // pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
@@ -408,24 +358,24 @@ static inline-class-member method GenericInlineClass|constructor#<T extends core
 static inline-class-member method GenericInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::GenericInlineClass|constructor#_#new#tearOff::T% it) → self::GenericInlineClass<self::GenericInlineClass|constructor#_#new#tearOff::T%>% /* = self::GenericInlineClass|constructor#_#new#tearOff::T% */
   return self::GenericInlineClass|constructor#<self::GenericInlineClass|constructor#_#new#tearOff::T%>(it);
 static inline-class-member method GenericInlineClass|test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|test::T%> /* = self::GenericInlineClass|test::T% */ #this, self::GenericInlineClass|test::T% t) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:24:19: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:25:14: Error: The getter 'it' isn't defined for the class 'GenericInlineClass<T>'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
-  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  self::GenericInlineClass|test::T% a1 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  self::GenericInlineClass|test::T% a2 = #this as{Unchecked} self::GenericInlineClass|test::T%;
+  invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:26:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
                     ^";
-  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
+  invalid-type b2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:27:16: Error: The static type of the explicit instantiation operand must be a generic function type but is 'T'.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  self::GenericInlineClass|test::T% c1 = let final self::GenericInlineClass|test::T% #t1 = t in let final void #t2 = self::_extension#0|set#it(#this, #t1) in #t1;
-  self::GenericInlineClass|test::T% c2 = let final self::GenericInlineClass|test::T% #t3 = t in let final void #t4 = self::_extension#0|set#it(#this, #t3) in #t3;
+  self::GenericInlineClass|test::T% c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:28:19: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = t; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = t;
+  self::GenericInlineClass|test::T% c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:29:14: Error: The setter 'it' isn't defined for the class 'GenericInlineClass<T>'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = t; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = t;
 }
 static inline-class-member method GenericInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::GenericInlineClass<self::GenericInlineClass|get#test::T%>% /* = self::GenericInlineClass|get#test::T% */ #this) → (self::GenericInlineClass|get#test::T%) → void
   return (self::GenericInlineClass|get#test::T% t) → void => self::GenericInlineClass|test<self::GenericInlineClass|get#test::T%>(#this, t);
@@ -504,14 +454,8 @@ static inline-class-member method DynamicInlineClass|constructor#(dynamic it)
 static inline-class-member method DynamicInlineClass|constructor#_#new#tearOff(dynamic it) → self::DynamicInlineClass /* = dynamic */
   return self::DynamicInlineClass|constructor#(it);
 static inline-class-member method DynamicInlineClass|test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → void {
-  dynamic a1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:70:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a1 = this.it;
-                  ^^" in #this{<unresolved>}.it;
-  dynamic a2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:71:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var a2 = it;
-             ^^" in #this{<unresolved>}.it;
+  dynamic a1 = #this as{Unchecked} dynamic;
+  dynamic a2 = #this as{Unchecked} dynamic;
   invalid-type b1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:72:21: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
     var b1 = this.it<int>; // Error
@@ -520,24 +464,18 @@ Try changing the operand or remove the type arguments.
 Try changing the operand or remove the type arguments.
     var b2 = it<int>; // Error
                ^";
-  core::int c1 = let final core::int #t5 = 42 in let final void #t6 = self::_extension#0|set#it(#this, #t5) in #t5;
-  core::int c2 = let final core::int #t7 = 42 in let final void #t8 = self::_extension#0|set#it(#this, #t7) in #t7;
-  dynamic d1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:76:19: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d1 = this.it();
-                  ^^" in #this{<unresolved>}.it();
-  dynamic d2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:77:14: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-    var d2 = it();
-             ^^" in #this{<unresolved>}.it();
-  dynamic d3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:78:19: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d3 = this.it.call();
-                  ^^" in #this{<unresolved>}.it{dynamic}.call();
-  dynamic d4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:79:14: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-    var d4 = it.call();
-             ^^" in #this{<unresolved>}.it{dynamic}.call();
+  core::int c1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:74:19: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c1 = this.it = 42; // Error, should not resolve to extension method.
+                  ^^" in #this{<unresolved>}.it = 42;
+  core::int c2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:75:14: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+    var c2 = it = 42; // Error, should not resolve to extension method.
+             ^^" in #this{<unresolved>}.it = 42;
+  dynamic d1 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d2 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d3 = (#this as{Unchecked} dynamic){dynamic}.call();
+  dynamic d4 = (#this as{Unchecked} dynamic){dynamic}.call();
 }
 static inline-class-member method DynamicInlineClass|get#test(lowered final self::DynamicInlineClass /* = dynamic */ #this) → () → void
   return () → void => self::DynamicInlineClass|test(#this);
@@ -658,19 +596,16 @@ Try correcting the name to the name of an existing setter, or defining a setter
 Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
   var d6 = genericFunctionInlineClass.it = <T>() => throw ''; // Error, should
                                       ^^" in genericFunctionInlineClass{<unresolved>}.it = <T extends core::Object? = dynamic>() → Never => throw "";
-  dynamic e1 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:142:31: Error: The getter 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing getter, or defining a getter or field named 'it'.
-  var e1 = dynamicInlineClass.it;
-                              ^^" in dynamicInlineClass{<unresolved>}.it;
+  dynamic e1 = dynamicInlineClass as{Unchecked} dynamic;
   invalid-type e2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:143:33: Error: The static type of the explicit instantiation operand must be a generic function type but is 'dynamic'.
 Try changing the operand or remove the type arguments.
   var e2 = dynamicInlineClass.it<int>; // Error
                                 ^";
-  dynamic e3 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:144:31: Error: The method 'it' isn't defined for the class 'DynamicInlineClass'.
-Try correcting the name to the name of an existing method, or defining a method named 'it'.
-  var e3 = dynamicInlineClass.it();
-                              ^^" in dynamicInlineClass{<unresolved>}.it();
-  core::String e4 = let final core::String #t9 = "42" in let final void #t10 = self::_extension#0|set#it(dynamicInlineClass, #t9) in #t9;
+  dynamic e3 = (dynamicInlineClass as{Unchecked} dynamic){dynamic}.call();
+  core::String e4 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:145:31: Error: The setter 'it' isn't defined for the class 'DynamicInlineClass'.
+Try correcting the name to the name of an existing setter, or defining a setter or field named 'it'.
+  var e4 = dynamicInlineClass.it = '42'; // Error, should not resolve
+                              ^^" in dynamicInlineClass{<unresolved>}.it = "42";
   core::int f1 = erroneousInlineClass as{Unchecked} core::int;
   invalid-type f2 = invalid-expression "pkg/front_end/testcases/extension_types/field_access.dart:149:34: Error: The static type of the explicit instantiation operand must be a generic function type but is 'int'.
 Try changing the operand or remove the type arguments.
@@ -765,13 +700,3 @@ Try correcting the name to the name of an existing setter, or defining a setter
 }
 static inline-class-member method PrivateInlineClass|get#test(lowered final self2::PrivateInlineClass /* = core::int */ #this) → () → void
   return () → void => self2::PrivateInlineClass|test(#this);
-
-
-Extra constant evaluation status:
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:74:24 -> IntConstant(42)
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:74:24 -> IntConstant(42)
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:75:19 -> IntConstant(42)
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:75:19 -> IntConstant(42)
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:145:36 -> StringConstant("42")
-Evaluated: VariableGet @ org-dartlang-testcase:///field_access.dart:145:36 -> StringConstant("42")
-Extra constant evaluation: evaluated: 182, effectively constant: 6

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart

@@ -0,0 +1,129 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by b
+// BSD-style license that can be found in the LICENSE file.
+
+extension type ET1(int i) {
+  ET1? operator +(ET1? i) => i;
+  int operator -() => i;
+  int operator [](int index) => i;
+  void operator []=(int index, int value) {}
+  void foo(int i) {}
+  int get getter => i;
+  void set setter(int value) {}
+}
+
+extension type ET2<T>(T t) {
+  ET2<T>? operator +(ET2<T>? t) => t;
+  T operator -() => t;
+  T operator [](int index) => t;
+  void operator []=(int index, T value) {}
+  void foo(T t) {}
+  T get getter => t;
+  void set setter(T value) {}
+}
+
+method1(ET1 et) {
+  et.foo(0); // Ok
+  et.foo; // Ok
+  et.setter = et.getter; // Ok
+  et + et; // Ok
+  -et; // Ok
+  et[0]; // Ok
+  et[0] = 0; // Ok
+}
+
+method2(ET1? et) {
+  et.foo(0); // Error
+  et.foo; // Error
+  et.setter = // Error
+  et.getter; // Error
+  et + et; // Error
+  -et; // Error
+  et[0]; // Error
+  et[0] = 0; // Error
+}
+
+method3<S>(S s, ET2<S> et) {
+  et.foo(s); // Ok
+  et.foo; // Ok
+  et.setter = et.getter; // Ok
+  et + et; // Ok
+  -et; // Ok
+  et[0]; // Ok
+  et[0] = s; // Ok
+}
+
+method4<S>(S s, ET2<S>? et) {
+  et.foo(s); // Error
+  et.foo; // Error
+  et.setter = // Error
+  et.getter; // Error
+  et + et; // Error
+  -et; // Error
+  et[0]; // Error
+  et[0] = s; // Error
+}
+
+method5<S, U extends ET2<S>>(S s, U et) {
+  et.foo(s); // Ok
+  et.foo; // Ok
+  et.setter = et.getter; // Ok
+  et + et; // Ok
+  -et; // Ok
+  et[0]; // Ok
+  et[0] = s; // Ok
+}
+
+method6<S, U extends ET2<S>>(S s, U? et) {
+  et.foo(s); // Error
+  et.foo; // Error
+  et.setter = // Error
+  et.getter; // Error
+  et + et; // Error
+  -et; // Error
+  et[0]; // Error
+  et[0] = s; // Error
+}
+
+method7<S, U extends ET2<S>, V extends U>(S s, V et) {
+  et.foo(s); // Ok
+  et.foo; // Ok
+  et.setter = et.getter; // Ok
+  et + et; // Ok
+  -et; // Ok
+  et[0]; // Ok
+  et[0] = s; // Ok
+}
+
+method8<S, U extends ET2<S>, V extends U>(S s, V? et) {
+  et.foo(s); // Error
+  et.foo; // Error
+  et.setter = // Error
+  et.getter; // Error
+  et + et; // Error
+  -et; // Error
+  et[0]; // Error
+  et[0] = s; // Error
+}
+
+method9<S, U extends ET2<S>, V extends U?>(S s, V et) {
+  et.foo(s); // Error
+  et.foo; // Error
+  et.setter = // Error
+  et.getter; // Error
+  et + et; // Error
+  -et; // Error
+  et[0]; // Error
+  et[0] = s; // Error
+}
+
+method10<S, U extends ET2<S>?, V extends U>(S s, V et) {
+  et.foo(s); // Error
+  et.foo; // Error
+  et.setter = // Error
+  et.getter; // Error
+  et + et; // Error
+  -et; // Error
+  et[0]; // Error
+  et[0] = s; // Error
+}

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart.strong.expect

@@ -0,0 +1,497 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(0); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+//   et[0] = 0; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type ET1(core::int i) {
+  abstract inline-class-member representation-field get i() → core::int;
+  operator + = self::ET1|+;
+  operator unary- = self::ET1|unary-;
+  operator [] = self::ET1|[];
+  operator []= = self::ET1|[]=;
+  method foo = self::ET1|foo;
+  method tearoff foo = self::ET1|get#foo;
+  get getter = self::ET1|get#getter;
+  set setter = self::ET1|set#setter;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2<T extends core::Object? = dynamic>(T% t) {
+  abstract inline-class-member representation-field get t() → T%;
+  operator + = self::ET2|+;
+  operator unary- = self::ET2|unary-;
+  operator [] = self::ET2|[];
+  operator []= = self::ET2|[]=;
+  method foo = self::ET2|foo;
+  method tearoff foo = self::ET2|get#foo;
+  get getter = self::ET2|get#getter;
+  set setter = self::ET2|set#setter;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static inline-class-member method ET1|constructor#(core::int i) → self::ET1 /* = core::int */ {
+  lowered final self::ET1 /* = core::int */ #this = i;
+  return #this;
+}
+static inline-class-member method ET1|constructor#_#new#tearOff(core::int i) → self::ET1 /* = core::int */
+  return self::ET1|constructor#(i);
+static inline-class-member method ET1|+(lowered final self::ET1 /* = core::int */ #this, self::ET1? /* = core::int? */ i) → self::ET1? /* = core::int? */
+  return i;
+static inline-class-member method ET1|unary-(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[](lowered final self::ET1 /* = core::int */ #this, core::int index) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[]=(lowered final self::ET1 /* = core::int */ #this, core::int index, core::int value) → void {}
+static inline-class-member method ET1|foo(lowered final self::ET1 /* = core::int */ #this, core::int i) → void {}
+static inline-class-member method ET1|get#foo(lowered final self::ET1 /* = core::int */ #this) → (core::int) → void
+  return (core::int i) → void => self::ET1|foo(#this, i);
+static inline-class-member method ET1|get#getter(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|set#setter(lowered final self::ET1 /* = core::int */ #this, core::int value) → void {}
+static inline-class-member method ET2|constructor#<T extends core::Object? = dynamic>(self::ET2|constructor#::T% t) → self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ {
+  lowered final self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ #this = t;
+  return #this;
+}
+static inline-class-member method ET2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::ET2|constructor#_#new#tearOff::T% t) → self::ET2<self::ET2|constructor#_#new#tearOff::T%>% /* = self::ET2|constructor#_#new#tearOff::T% */
+  return self::ET2|constructor#<self::ET2|constructor#_#new#tearOff::T%>(t);
+static inline-class-member method ET2|+<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|+::T%> /* = self::ET2|+::T% */ #this, self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */ t) → self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */
+  return t;
+static inline-class-member method ET2|unary-<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|unary-::T%> /* = self::ET2|unary-::T% */ #this) → self::ET2|unary-::T%
+  return #this as{Unchecked} self::ET2|unary-::T%;
+static inline-class-member method ET2|[]<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]::T%> /* = self::ET2|[]::T% */ #this, core::int index) → self::ET2|[]::T%
+  return #this as{Unchecked} self::ET2|[]::T%;
+static inline-class-member method ET2|[]=<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]=::T%> /* = self::ET2|[]=::T% */ #this, core::int index, self::ET2|[]=::T% value) → void {}
+static inline-class-member method ET2|foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|foo::T%> /* = self::ET2|foo::T% */ #this, self::ET2|foo::T% t) → void {}
+static inline-class-member method ET2|get#foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#foo::T%>% /* = self::ET2|get#foo::T% */ #this) → (self::ET2|get#foo::T%) → void
+  return (self::ET2|get#foo::T% t) → void => self::ET2|foo<self::ET2|get#foo::T%>(#this, t);
+static inline-class-member method ET2|get#getter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#getter::T%> /* = self::ET2|get#getter::T% */ #this) → self::ET2|get#getter::T%
+  return #this as{Unchecked} self::ET2|get#getter::T%;
+static inline-class-member method ET2|set#setter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|set#setter::T%> /* = self::ET2|set#setter::T% */ #this, self::ET2|set#setter::T% value) → void {}
+static method method1(self::ET1 /* = core::int */ et) → dynamic {
+  self::ET1|foo(et, 0);
+  self::ET1|get#foo(et);
+  self::ET1|set#setter(et, self::ET1|get#getter(et));
+  self::ET1|+(et, et);
+  self::ET1|unary-(et);
+  self::ET1|[](et, 0);
+  self::ET1|[]=(et, 0, 0);
+}
+static method method2(self::ET1? /* = core::int? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(0); // Error
+     ^^^" in self::ET1|foo(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET1|get#foo(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET1|set#setter(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET1|get#getter(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET1|+(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET1|unary-(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET1|[](et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+  et[0] = 0; // Error
+    ^" in self::ET1|[]=(et, 0, 0);
+}
+static method method3<S extends core::Object? = dynamic>(self::method3::S% s, self::ET2<self::method3::S%> /* = self::method3::S% */ et) → dynamic {
+  self::ET2|foo<self::method3::S%>(et, s);
+  self::ET2|get#foo<self::method3::S%>(et);
+  self::ET2|set#setter<self::method3::S%>(et, self::ET2|get#getter<self::method3::S%>(et));
+  self::ET2|+<self::method3::S%>(et, et);
+  self::ET2|unary-<self::method3::S%>(et);
+  self::ET2|[]<self::method3::S%>(et, 0);
+  self::ET2|[]=<self::method3::S%>(et, 0, s);
+}
+static method method4<S extends core::Object? = dynamic>(self::method4::S% s, self::ET2<self::method4::S%>? /* = self::method4::S? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method4::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method4::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method4::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method4::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method4::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method4::S%>(et, 0, s);
+}
+static method method5<S extends core::Object? = dynamic, U extends self::ET2<self::method5::S%> /* = self::method5::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method5::S% s, self::method5::U% et) → dynamic {
+  self::ET2|foo<self::method5::S%>(et, s);
+  self::ET2|get#foo<self::method5::S%>(et);
+  self::ET2|set#setter<self::method5::S%>(et, self::ET2|get#getter<self::method5::S%>(et));
+  self::ET2|+<self::method5::S%>(et, et);
+  self::ET2|unary-<self::method5::S%>(et);
+  self::ET2|[]<self::method5::S%>(et, 0);
+  self::ET2|[]=<self::method5::S%>(et, 0, s);
+}
+static method method6<S extends core::Object? = dynamic, U extends self::ET2<self::method6::S%> /* = self::method6::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method6::S% s, self::method6::U? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method6::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method6::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method6::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method6::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method6::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method6::S%>(et, 0, s);
+}
+static method method7<S extends core::Object? = dynamic, U extends self::ET2<self::method7::S%> /* = self::method7::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method7::U% = self::ET2<dynamic> /* = dynamic */>(self::method7::S% s, self::method7::V% et) → dynamic {
+  self::ET2|foo<self::method7::S%>(et, s);
+  self::ET2|get#foo<self::method7::S%>(et);
+  self::ET2|set#setter<self::method7::S%>(et, self::ET2|get#getter<self::method7::S%>(et));
+  self::ET2|+<self::method7::S%>(et, et);
+  self::ET2|unary-<self::method7::S%>(et);
+  self::ET2|[]<self::method7::S%>(et, 0);
+  self::ET2|[]=<self::method7::S%>(et, 0, s);
+}
+static method method8<S extends core::Object? = dynamic, U extends self::ET2<self::method8::S%> /* = self::method8::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method8::U% = self::ET2<dynamic> /* = dynamic */>(self::method8::S% s, self::method8::V? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method8::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method8::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method8::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method8::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method8::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method8::S%>(et, 0, s);
+}
+static method method9<S extends core::Object? = dynamic, U extends self::ET2<self::method9::S%> /* = self::method9::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method9::U? = self::ET2<dynamic>? /* = dynamic */>(self::method9::S% s, self::method9::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method9::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method9::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method9::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method9::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method9::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method9::S%>(et, 0, s);
+}
+static method method10<S extends core::Object? = dynamic, U extends self::ET2<self::method10::S%>? /* = self::method10::S? */ = self::ET2<dynamic>? /* = dynamic */, V extends self::method10::U% = self::ET2<dynamic>? /* = dynamic */>(self::method10::S% s, self::method10::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method10::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method10::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method10::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method10::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method10::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method10::S%>(et, 0, s);
+}

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart.strong.transformed.expect

@@ -0,0 +1,497 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(0); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+//   et[0] = 0; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type ET1(core::int i) {
+  abstract inline-class-member representation-field get i() → core::int;
+  operator + = self::ET1|+;
+  operator unary- = self::ET1|unary-;
+  operator [] = self::ET1|[];
+  operator []= = self::ET1|[]=;
+  method foo = self::ET1|foo;
+  method tearoff foo = self::ET1|get#foo;
+  get getter = self::ET1|get#getter;
+  set setter = self::ET1|set#setter;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2<T extends core::Object? = dynamic>(T% t) {
+  abstract inline-class-member representation-field get t() → T%;
+  operator + = self::ET2|+;
+  operator unary- = self::ET2|unary-;
+  operator [] = self::ET2|[];
+  operator []= = self::ET2|[]=;
+  method foo = self::ET2|foo;
+  method tearoff foo = self::ET2|get#foo;
+  get getter = self::ET2|get#getter;
+  set setter = self::ET2|set#setter;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static inline-class-member method ET1|constructor#(core::int i) → self::ET1 /* = core::int */ {
+  lowered final self::ET1 /* = core::int */ #this = i;
+  return #this;
+}
+static inline-class-member method ET1|constructor#_#new#tearOff(core::int i) → self::ET1 /* = core::int */
+  return self::ET1|constructor#(i);
+static inline-class-member method ET1|+(lowered final self::ET1 /* = core::int */ #this, self::ET1? /* = core::int? */ i) → self::ET1? /* = core::int? */
+  return i;
+static inline-class-member method ET1|unary-(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[](lowered final self::ET1 /* = core::int */ #this, core::int index) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[]=(lowered final self::ET1 /* = core::int */ #this, core::int index, core::int value) → void {}
+static inline-class-member method ET1|foo(lowered final self::ET1 /* = core::int */ #this, core::int i) → void {}
+static inline-class-member method ET1|get#foo(lowered final self::ET1 /* = core::int */ #this) → (core::int) → void
+  return (core::int i) → void => self::ET1|foo(#this, i);
+static inline-class-member method ET1|get#getter(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|set#setter(lowered final self::ET1 /* = core::int */ #this, core::int value) → void {}
+static inline-class-member method ET2|constructor#<T extends core::Object? = dynamic>(self::ET2|constructor#::T% t) → self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ {
+  lowered final self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ #this = t;
+  return #this;
+}
+static inline-class-member method ET2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::ET2|constructor#_#new#tearOff::T% t) → self::ET2<self::ET2|constructor#_#new#tearOff::T%>% /* = self::ET2|constructor#_#new#tearOff::T% */
+  return self::ET2|constructor#<self::ET2|constructor#_#new#tearOff::T%>(t);
+static inline-class-member method ET2|+<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|+::T%> /* = self::ET2|+::T% */ #this, self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */ t) → self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */
+  return t;
+static inline-class-member method ET2|unary-<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|unary-::T%> /* = self::ET2|unary-::T% */ #this) → self::ET2|unary-::T%
+  return #this as{Unchecked} self::ET2|unary-::T%;
+static inline-class-member method ET2|[]<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]::T%> /* = self::ET2|[]::T% */ #this, core::int index) → self::ET2|[]::T%
+  return #this as{Unchecked} self::ET2|[]::T%;
+static inline-class-member method ET2|[]=<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]=::T%> /* = self::ET2|[]=::T% */ #this, core::int index, self::ET2|[]=::T% value) → void {}
+static inline-class-member method ET2|foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|foo::T%> /* = self::ET2|foo::T% */ #this, self::ET2|foo::T% t) → void {}
+static inline-class-member method ET2|get#foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#foo::T%>% /* = self::ET2|get#foo::T% */ #this) → (self::ET2|get#foo::T%) → void
+  return (self::ET2|get#foo::T% t) → void => self::ET2|foo<self::ET2|get#foo::T%>(#this, t);
+static inline-class-member method ET2|get#getter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#getter::T%> /* = self::ET2|get#getter::T% */ #this) → self::ET2|get#getter::T%
+  return #this as{Unchecked} self::ET2|get#getter::T%;
+static inline-class-member method ET2|set#setter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|set#setter::T%> /* = self::ET2|set#setter::T% */ #this, self::ET2|set#setter::T% value) → void {}
+static method method1(self::ET1 /* = core::int */ et) → dynamic {
+  self::ET1|foo(et, 0);
+  self::ET1|get#foo(et);
+  self::ET1|set#setter(et, self::ET1|get#getter(et));
+  self::ET1|+(et, et);
+  self::ET1|unary-(et);
+  self::ET1|[](et, 0);
+  self::ET1|[]=(et, 0, 0);
+}
+static method method2(self::ET1? /* = core::int? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(0); // Error
+     ^^^" in self::ET1|foo(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET1|get#foo(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET1|set#setter(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET1|get#getter(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET1|+(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET1|unary-(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET1|[](et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+  et[0] = 0; // Error
+    ^" in self::ET1|[]=(et, 0, 0);
+}
+static method method3<S extends core::Object? = dynamic>(self::method3::S% s, self::ET2<self::method3::S%> /* = self::method3::S% */ et) → dynamic {
+  self::ET2|foo<self::method3::S%>(et, s);
+  self::ET2|get#foo<self::method3::S%>(et);
+  self::ET2|set#setter<self::method3::S%>(et, self::ET2|get#getter<self::method3::S%>(et));
+  self::ET2|+<self::method3::S%>(et, et);
+  self::ET2|unary-<self::method3::S%>(et);
+  self::ET2|[]<self::method3::S%>(et, 0);
+  self::ET2|[]=<self::method3::S%>(et, 0, s);
+}
+static method method4<S extends core::Object? = dynamic>(self::method4::S% s, self::ET2<self::method4::S%>? /* = self::method4::S? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method4::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method4::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method4::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method4::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method4::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method4::S%>(et, 0, s);
+}
+static method method5<S extends core::Object? = dynamic, U extends self::ET2<self::method5::S%> /* = self::method5::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method5::S% s, self::method5::U% et) → dynamic {
+  self::ET2|foo<self::method5::S%>(et, s);
+  self::ET2|get#foo<self::method5::S%>(et);
+  self::ET2|set#setter<self::method5::S%>(et, self::ET2|get#getter<self::method5::S%>(et));
+  self::ET2|+<self::method5::S%>(et, et);
+  self::ET2|unary-<self::method5::S%>(et);
+  self::ET2|[]<self::method5::S%>(et, 0);
+  self::ET2|[]=<self::method5::S%>(et, 0, s);
+}
+static method method6<S extends core::Object? = dynamic, U extends self::ET2<self::method6::S%> /* = self::method6::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method6::S% s, self::method6::U? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method6::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method6::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method6::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method6::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method6::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method6::S%>(et, 0, s);
+}
+static method method7<S extends core::Object? = dynamic, U extends self::ET2<self::method7::S%> /* = self::method7::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method7::U% = self::ET2<dynamic> /* = dynamic */>(self::method7::S% s, self::method7::V% et) → dynamic {
+  self::ET2|foo<self::method7::S%>(et, s);
+  self::ET2|get#foo<self::method7::S%>(et);
+  self::ET2|set#setter<self::method7::S%>(et, self::ET2|get#getter<self::method7::S%>(et));
+  self::ET2|+<self::method7::S%>(et, et);
+  self::ET2|unary-<self::method7::S%>(et);
+  self::ET2|[]<self::method7::S%>(et, 0);
+  self::ET2|[]=<self::method7::S%>(et, 0, s);
+}
+static method method8<S extends core::Object? = dynamic, U extends self::ET2<self::method8::S%> /* = self::method8::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method8::U% = self::ET2<dynamic> /* = dynamic */>(self::method8::S% s, self::method8::V? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method8::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method8::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method8::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method8::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method8::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method8::S%>(et, 0, s);
+}
+static method method9<S extends core::Object? = dynamic, U extends self::ET2<self::method9::S%> /* = self::method9::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method9::U? = self::ET2<dynamic>? /* = dynamic */>(self::method9::S% s, self::method9::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method9::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method9::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method9::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method9::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method9::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method9::S%>(et, 0, s);
+}
+static method method10<S extends core::Object? = dynamic, U extends self::ET2<self::method10::S%>? /* = self::method10::S? */ = self::ET2<dynamic>? /* = dynamic */, V extends self::method10::U% = self::ET2<dynamic>? /* = dynamic */>(self::method10::S% s, self::method10::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method10::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method10::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method10::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method10::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method10::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method10::S%>(et, 0, s);
+}

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart.textual_outline.expect

@@ -0,0 +1,28 @@
+extension type ET1(int i) {
+  ET1? operator +(ET1? i) => i;
+  int operator -() => i;
+  int operator [](int index) => i;
+  void operator []=(int index, int value) {}
+  void foo(int i) {}
+  int get getter => i;
+  void set setter(int value) {}
+}
+extension type ET2<T>(T t) {
+  ET2<T>? operator +(ET2<T>? t) => t;
+  T operator -() => t;
+  T operator [](int index) => t;
+  void operator []=(int index, T value) {}
+  void foo(T t) {}
+  T get getter => t;
+  void set setter(T value) {}
+}
+method1(ET1 et) {}
+method2(ET1? et) {}
+method3<S>(S s, ET2<S> et) {}
+method4<S>(S s, ET2<S>? et) {}
+method5<S, U extends ET2<S>>(S s, U et) {}
+method6<S, U extends ET2<S>>(S s, U? et) {}
+method7<S, U extends ET2<S>, V extends U>(S s, V et) {}
+method8<S, U extends ET2<S>, V extends U>(S s, V? et) {}
+method9<S, U extends ET2<S>, V extends U?>(S s, V et) {}
+method10<S, U extends ET2<S>?, V extends U>(S s, V et) {}

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart.textual_outline_modelled.expect

@@ -0,0 +1,28 @@
+extension type ET1(int i) {
+  ET1? operator +(ET1? i) => i;
+  int get getter => i;
+  int operator -() => i;
+  int operator [](int index) => i;
+  void foo(int i) {}
+  void operator []=(int index, int value) {}
+  void set setter(int value) {}
+}
+extension type ET2<T>(T t) {
+  ET2<T>? operator +(ET2<T>? t) => t;
+  T get getter => t;
+  T operator -() => t;
+  T operator [](int index) => t;
+  void foo(T t) {}
+  void operator []=(int index, T value) {}
+  void set setter(T value) {}
+}
+method1(ET1 et) {}
+method10<S, U extends ET2<S>?, V extends U>(S s, V et) {}
+method2(ET1? et) {}
+method3<S>(S s, ET2<S> et) {}
+method4<S>(S s, ET2<S>? et) {}
+method5<S, U extends ET2<S>>(S s, U et) {}
+method6<S, U extends ET2<S>>(S s, U? et) {}
+method7<S, U extends ET2<S>, V extends U>(S s, V et) {}
+method8<S, U extends ET2<S>, V extends U>(S s, V? et) {}
+method9<S, U extends ET2<S>, V extends U?>(S s, V et) {}

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart.weak.expect

@@ -0,0 +1,497 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(0); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+//   et[0] = 0; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type ET1(core::int i) {
+  abstract inline-class-member representation-field get i() → core::int;
+  operator + = self::ET1|+;
+  operator unary- = self::ET1|unary-;
+  operator [] = self::ET1|[];
+  operator []= = self::ET1|[]=;
+  method foo = self::ET1|foo;
+  method tearoff foo = self::ET1|get#foo;
+  get getter = self::ET1|get#getter;
+  set setter = self::ET1|set#setter;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2<T extends core::Object? = dynamic>(T% t) {
+  abstract inline-class-member representation-field get t() → T%;
+  operator + = self::ET2|+;
+  operator unary- = self::ET2|unary-;
+  operator [] = self::ET2|[];
+  operator []= = self::ET2|[]=;
+  method foo = self::ET2|foo;
+  method tearoff foo = self::ET2|get#foo;
+  get getter = self::ET2|get#getter;
+  set setter = self::ET2|set#setter;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static inline-class-member method ET1|constructor#(core::int i) → self::ET1 /* = core::int */ {
+  lowered final self::ET1 /* = core::int */ #this = i;
+  return #this;
+}
+static inline-class-member method ET1|constructor#_#new#tearOff(core::int i) → self::ET1 /* = core::int */
+  return self::ET1|constructor#(i);
+static inline-class-member method ET1|+(lowered final self::ET1 /* = core::int */ #this, self::ET1? /* = core::int? */ i) → self::ET1? /* = core::int? */
+  return i;
+static inline-class-member method ET1|unary-(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[](lowered final self::ET1 /* = core::int */ #this, core::int index) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[]=(lowered final self::ET1 /* = core::int */ #this, core::int index, core::int value) → void {}
+static inline-class-member method ET1|foo(lowered final self::ET1 /* = core::int */ #this, core::int i) → void {}
+static inline-class-member method ET1|get#foo(lowered final self::ET1 /* = core::int */ #this) → (core::int) → void
+  return (core::int i) → void => self::ET1|foo(#this, i);
+static inline-class-member method ET1|get#getter(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|set#setter(lowered final self::ET1 /* = core::int */ #this, core::int value) → void {}
+static inline-class-member method ET2|constructor#<T extends core::Object? = dynamic>(self::ET2|constructor#::T% t) → self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ {
+  lowered final self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ #this = t;
+  return #this;
+}
+static inline-class-member method ET2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::ET2|constructor#_#new#tearOff::T% t) → self::ET2<self::ET2|constructor#_#new#tearOff::T%>% /* = self::ET2|constructor#_#new#tearOff::T% */
+  return self::ET2|constructor#<self::ET2|constructor#_#new#tearOff::T%>(t);
+static inline-class-member method ET2|+<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|+::T%> /* = self::ET2|+::T% */ #this, self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */ t) → self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */
+  return t;
+static inline-class-member method ET2|unary-<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|unary-::T%> /* = self::ET2|unary-::T% */ #this) → self::ET2|unary-::T%
+  return #this as{Unchecked} self::ET2|unary-::T%;
+static inline-class-member method ET2|[]<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]::T%> /* = self::ET2|[]::T% */ #this, core::int index) → self::ET2|[]::T%
+  return #this as{Unchecked} self::ET2|[]::T%;
+static inline-class-member method ET2|[]=<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]=::T%> /* = self::ET2|[]=::T% */ #this, core::int index, self::ET2|[]=::T% value) → void {}
+static inline-class-member method ET2|foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|foo::T%> /* = self::ET2|foo::T% */ #this, self::ET2|foo::T% t) → void {}
+static inline-class-member method ET2|get#foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#foo::T%>% /* = self::ET2|get#foo::T% */ #this) → (self::ET2|get#foo::T%) → void
+  return (self::ET2|get#foo::T% t) → void => self::ET2|foo<self::ET2|get#foo::T%>(#this, t);
+static inline-class-member method ET2|get#getter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#getter::T%> /* = self::ET2|get#getter::T% */ #this) → self::ET2|get#getter::T%
+  return #this as{Unchecked} self::ET2|get#getter::T%;
+static inline-class-member method ET2|set#setter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|set#setter::T%> /* = self::ET2|set#setter::T% */ #this, self::ET2|set#setter::T% value) → void {}
+static method method1(self::ET1 /* = core::int */ et) → dynamic {
+  self::ET1|foo(et, 0);
+  self::ET1|get#foo(et);
+  self::ET1|set#setter(et, self::ET1|get#getter(et));
+  self::ET1|+(et, et);
+  self::ET1|unary-(et);
+  self::ET1|[](et, 0);
+  self::ET1|[]=(et, 0, 0);
+}
+static method method2(self::ET1? /* = core::int? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(0); // Error
+     ^^^" in self::ET1|foo(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET1|get#foo(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET1|set#setter(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET1|get#getter(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET1|+(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET1|unary-(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET1|[](et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+  et[0] = 0; // Error
+    ^" in self::ET1|[]=(et, 0, 0);
+}
+static method method3<S extends core::Object? = dynamic>(self::method3::S% s, self::ET2<self::method3::S%> /* = self::method3::S% */ et) → dynamic {
+  self::ET2|foo<self::method3::S%>(et, s);
+  self::ET2|get#foo<self::method3::S%>(et);
+  self::ET2|set#setter<self::method3::S%>(et, self::ET2|get#getter<self::method3::S%>(et));
+  self::ET2|+<self::method3::S%>(et, et);
+  self::ET2|unary-<self::method3::S%>(et);
+  self::ET2|[]<self::method3::S%>(et, 0);
+  self::ET2|[]=<self::method3::S%>(et, 0, s);
+}
+static method method4<S extends core::Object? = dynamic>(self::method4::S% s, self::ET2<self::method4::S%>? /* = self::method4::S? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method4::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method4::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method4::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method4::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method4::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method4::S%>(et, 0, s);
+}
+static method method5<S extends core::Object? = dynamic, U extends self::ET2<self::method5::S%> /* = self::method5::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method5::S% s, self::method5::U% et) → dynamic {
+  self::ET2|foo<self::method5::S%>(et, s);
+  self::ET2|get#foo<self::method5::S%>(et);
+  self::ET2|set#setter<self::method5::S%>(et, self::ET2|get#getter<self::method5::S%>(et));
+  self::ET2|+<self::method5::S%>(et, et);
+  self::ET2|unary-<self::method5::S%>(et);
+  self::ET2|[]<self::method5::S%>(et, 0);
+  self::ET2|[]=<self::method5::S%>(et, 0, s);
+}
+static method method6<S extends core::Object? = dynamic, U extends self::ET2<self::method6::S%> /* = self::method6::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method6::S% s, self::method6::U? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method6::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method6::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method6::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method6::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method6::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method6::S%>(et, 0, s);
+}
+static method method7<S extends core::Object? = dynamic, U extends self::ET2<self::method7::S%> /* = self::method7::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method7::U% = self::ET2<dynamic> /* = dynamic */>(self::method7::S% s, self::method7::V% et) → dynamic {
+  self::ET2|foo<self::method7::S%>(et, s);
+  self::ET2|get#foo<self::method7::S%>(et);
+  self::ET2|set#setter<self::method7::S%>(et, self::ET2|get#getter<self::method7::S%>(et));
+  self::ET2|+<self::method7::S%>(et, et);
+  self::ET2|unary-<self::method7::S%>(et);
+  self::ET2|[]<self::method7::S%>(et, 0);
+  self::ET2|[]=<self::method7::S%>(et, 0, s);
+}
+static method method8<S extends core::Object? = dynamic, U extends self::ET2<self::method8::S%> /* = self::method8::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method8::U% = self::ET2<dynamic> /* = dynamic */>(self::method8::S% s, self::method8::V? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method8::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method8::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method8::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method8::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method8::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method8::S%>(et, 0, s);
+}
+static method method9<S extends core::Object? = dynamic, U extends self::ET2<self::method9::S%> /* = self::method9::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method9::U? = self::ET2<dynamic>? /* = dynamic */>(self::method9::S% s, self::method9::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method9::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method9::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method9::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method9::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method9::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method9::S%>(et, 0, s);
+}
+static method method10<S extends core::Object? = dynamic, U extends self::ET2<self::method10::S%>? /* = self::method10::S? */ = self::ET2<dynamic>? /* = dynamic */, V extends self::method10::U% = self::ET2<dynamic>? /* = dynamic */>(self::method10::S% s, self::method10::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method10::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method10::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method10::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method10::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method10::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method10::S%>(et, 0, s);
+}

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart.weak.modular.expect

@@ -0,0 +1,497 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(0); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+//   et[0] = 0; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type ET1(core::int i) {
+  abstract inline-class-member representation-field get i() → core::int;
+  operator + = self::ET1|+;
+  operator unary- = self::ET1|unary-;
+  operator [] = self::ET1|[];
+  operator []= = self::ET1|[]=;
+  method foo = self::ET1|foo;
+  method tearoff foo = self::ET1|get#foo;
+  get getter = self::ET1|get#getter;
+  set setter = self::ET1|set#setter;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2<T extends core::Object? = dynamic>(T% t) {
+  abstract inline-class-member representation-field get t() → T%;
+  operator + = self::ET2|+;
+  operator unary- = self::ET2|unary-;
+  operator [] = self::ET2|[];
+  operator []= = self::ET2|[]=;
+  method foo = self::ET2|foo;
+  method tearoff foo = self::ET2|get#foo;
+  get getter = self::ET2|get#getter;
+  set setter = self::ET2|set#setter;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static inline-class-member method ET1|constructor#(core::int i) → self::ET1 /* = core::int */ {
+  lowered final self::ET1 /* = core::int */ #this = i;
+  return #this;
+}
+static inline-class-member method ET1|constructor#_#new#tearOff(core::int i) → self::ET1 /* = core::int */
+  return self::ET1|constructor#(i);
+static inline-class-member method ET1|+(lowered final self::ET1 /* = core::int */ #this, self::ET1? /* = core::int? */ i) → self::ET1? /* = core::int? */
+  return i;
+static inline-class-member method ET1|unary-(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[](lowered final self::ET1 /* = core::int */ #this, core::int index) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[]=(lowered final self::ET1 /* = core::int */ #this, core::int index, core::int value) → void {}
+static inline-class-member method ET1|foo(lowered final self::ET1 /* = core::int */ #this, core::int i) → void {}
+static inline-class-member method ET1|get#foo(lowered final self::ET1 /* = core::int */ #this) → (core::int) → void
+  return (core::int i) → void => self::ET1|foo(#this, i);
+static inline-class-member method ET1|get#getter(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|set#setter(lowered final self::ET1 /* = core::int */ #this, core::int value) → void {}
+static inline-class-member method ET2|constructor#<T extends core::Object? = dynamic>(self::ET2|constructor#::T% t) → self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ {
+  lowered final self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ #this = t;
+  return #this;
+}
+static inline-class-member method ET2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::ET2|constructor#_#new#tearOff::T% t) → self::ET2<self::ET2|constructor#_#new#tearOff::T%>% /* = self::ET2|constructor#_#new#tearOff::T% */
+  return self::ET2|constructor#<self::ET2|constructor#_#new#tearOff::T%>(t);
+static inline-class-member method ET2|+<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|+::T%> /* = self::ET2|+::T% */ #this, self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */ t) → self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */
+  return t;
+static inline-class-member method ET2|unary-<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|unary-::T%> /* = self::ET2|unary-::T% */ #this) → self::ET2|unary-::T%
+  return #this as{Unchecked} self::ET2|unary-::T%;
+static inline-class-member method ET2|[]<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]::T%> /* = self::ET2|[]::T% */ #this, core::int index) → self::ET2|[]::T%
+  return #this as{Unchecked} self::ET2|[]::T%;
+static inline-class-member method ET2|[]=<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]=::T%> /* = self::ET2|[]=::T% */ #this, core::int index, self::ET2|[]=::T% value) → void {}
+static inline-class-member method ET2|foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|foo::T%> /* = self::ET2|foo::T% */ #this, self::ET2|foo::T% t) → void {}
+static inline-class-member method ET2|get#foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#foo::T%>% /* = self::ET2|get#foo::T% */ #this) → (self::ET2|get#foo::T%) → void
+  return (self::ET2|get#foo::T% t) → void => self::ET2|foo<self::ET2|get#foo::T%>(#this, t);
+static inline-class-member method ET2|get#getter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#getter::T%> /* = self::ET2|get#getter::T% */ #this) → self::ET2|get#getter::T%
+  return #this as{Unchecked} self::ET2|get#getter::T%;
+static inline-class-member method ET2|set#setter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|set#setter::T%> /* = self::ET2|set#setter::T% */ #this, self::ET2|set#setter::T% value) → void {}
+static method method1(self::ET1 /* = core::int */ et) → dynamic {
+  self::ET1|foo(et, 0);
+  self::ET1|get#foo(et);
+  self::ET1|set#setter(et, self::ET1|get#getter(et));
+  self::ET1|+(et, et);
+  self::ET1|unary-(et);
+  self::ET1|[](et, 0);
+  self::ET1|[]=(et, 0, 0);
+}
+static method method2(self::ET1? /* = core::int? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(0); // Error
+     ^^^" in self::ET1|foo(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET1|get#foo(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET1|set#setter(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET1|get#getter(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET1|+(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET1|unary-(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET1|[](et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+  et[0] = 0; // Error
+    ^" in self::ET1|[]=(et, 0, 0);
+}
+static method method3<S extends core::Object? = dynamic>(self::method3::S% s, self::ET2<self::method3::S%> /* = self::method3::S% */ et) → dynamic {
+  self::ET2|foo<self::method3::S%>(et, s);
+  self::ET2|get#foo<self::method3::S%>(et);
+  self::ET2|set#setter<self::method3::S%>(et, self::ET2|get#getter<self::method3::S%>(et));
+  self::ET2|+<self::method3::S%>(et, et);
+  self::ET2|unary-<self::method3::S%>(et);
+  self::ET2|[]<self::method3::S%>(et, 0);
+  self::ET2|[]=<self::method3::S%>(et, 0, s);
+}
+static method method4<S extends core::Object? = dynamic>(self::method4::S% s, self::ET2<self::method4::S%>? /* = self::method4::S? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method4::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method4::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method4::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method4::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method4::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method4::S%>(et, 0, s);
+}
+static method method5<S extends core::Object? = dynamic, U extends self::ET2<self::method5::S%> /* = self::method5::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method5::S% s, self::method5::U% et) → dynamic {
+  self::ET2|foo<self::method5::S%>(et, s);
+  self::ET2|get#foo<self::method5::S%>(et);
+  self::ET2|set#setter<self::method5::S%>(et, self::ET2|get#getter<self::method5::S%>(et));
+  self::ET2|+<self::method5::S%>(et, et);
+  self::ET2|unary-<self::method5::S%>(et);
+  self::ET2|[]<self::method5::S%>(et, 0);
+  self::ET2|[]=<self::method5::S%>(et, 0, s);
+}
+static method method6<S extends core::Object? = dynamic, U extends self::ET2<self::method6::S%> /* = self::method6::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method6::S% s, self::method6::U? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method6::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method6::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method6::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method6::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method6::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method6::S%>(et, 0, s);
+}
+static method method7<S extends core::Object? = dynamic, U extends self::ET2<self::method7::S%> /* = self::method7::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method7::U% = self::ET2<dynamic> /* = dynamic */>(self::method7::S% s, self::method7::V% et) → dynamic {
+  self::ET2|foo<self::method7::S%>(et, s);
+  self::ET2|get#foo<self::method7::S%>(et);
+  self::ET2|set#setter<self::method7::S%>(et, self::ET2|get#getter<self::method7::S%>(et));
+  self::ET2|+<self::method7::S%>(et, et);
+  self::ET2|unary-<self::method7::S%>(et);
+  self::ET2|[]<self::method7::S%>(et, 0);
+  self::ET2|[]=<self::method7::S%>(et, 0, s);
+}
+static method method8<S extends core::Object? = dynamic, U extends self::ET2<self::method8::S%> /* = self::method8::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method8::U% = self::ET2<dynamic> /* = dynamic */>(self::method8::S% s, self::method8::V? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method8::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method8::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method8::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method8::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method8::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method8::S%>(et, 0, s);
+}
+static method method9<S extends core::Object? = dynamic, U extends self::ET2<self::method9::S%> /* = self::method9::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method9::U? = self::ET2<dynamic>? /* = dynamic */>(self::method9::S% s, self::method9::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method9::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method9::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method9::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method9::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method9::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method9::S%>(et, 0, s);
+}
+static method method10<S extends core::Object? = dynamic, U extends self::ET2<self::method10::S%>? /* = self::method10::S? */ = self::ET2<dynamic>? /* = dynamic */, V extends self::method10::U% = self::ET2<dynamic>? /* = dynamic */>(self::method10::S% s, self::method10::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method10::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method10::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method10::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method10::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method10::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method10::S%>(et, 0, s);
+}

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart.weak.outline.expect

@@ -0,0 +1,90 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+extension type ET1(core::int i) {
+  abstract inline-class-member representation-field get i() → core::int;
+  operator + = self::ET1|+;
+  operator unary- = self::ET1|unary-;
+  operator [] = self::ET1|[];
+  operator []= = self::ET1|[]=;
+  method foo = self::ET1|foo;
+  method tearoff foo = self::ET1|get#foo;
+  get getter = self::ET1|get#getter;
+  set setter = self::ET1|set#setter;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2<T extends core::Object? = dynamic>(T% t) {
+  abstract inline-class-member representation-field get t() → T%;
+  operator + = self::ET2|+;
+  operator unary- = self::ET2|unary-;
+  operator [] = self::ET2|[];
+  operator []= = self::ET2|[]=;
+  method foo = self::ET2|foo;
+  method tearoff foo = self::ET2|get#foo;
+  get getter = self::ET2|get#getter;
+  set setter = self::ET2|set#setter;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static inline-class-member method ET1|constructor#(core::int i) → self::ET1 /* = core::int */
+  ;
+static inline-class-member method ET1|constructor#_#new#tearOff(core::int i) → self::ET1 /* = core::int */
+  return self::ET1|constructor#(i);
+static inline-class-member method ET1|+(lowered final self::ET1 /* = core::int */ #this, self::ET1? /* = core::int? */ i) → self::ET1? /* = core::int? */
+  ;
+static inline-class-member method ET1|unary-(lowered final self::ET1 /* = core::int */ #this) → core::int
+  ;
+static inline-class-member method ET1|[](lowered final self::ET1 /* = core::int */ #this, core::int index) → core::int
+  ;
+static inline-class-member method ET1|[]=(lowered final self::ET1 /* = core::int */ #this, core::int index, core::int value) → void
+  ;
+static inline-class-member method ET1|foo(lowered final self::ET1 /* = core::int */ #this, core::int i) → void
+  ;
+static inline-class-member method ET1|get#foo(lowered final self::ET1 /* = core::int */ #this) → (core::int) → void
+  return (core::int i) → void => self::ET1|foo(#this, i);
+static inline-class-member method ET1|get#getter(lowered final self::ET1 /* = core::int */ #this) → core::int
+  ;
+static inline-class-member method ET1|set#setter(lowered final self::ET1 /* = core::int */ #this, core::int value) → void
+  ;
+static inline-class-member method ET2|constructor#<T extends core::Object? = dynamic>(self::ET2|constructor#::T% t) → self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */
+  ;
+static inline-class-member method ET2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::ET2|constructor#_#new#tearOff::T% t) → self::ET2<self::ET2|constructor#_#new#tearOff::T%>% /* = self::ET2|constructor#_#new#tearOff::T% */
+  return self::ET2|constructor#<self::ET2|constructor#_#new#tearOff::T%>(t);
+static inline-class-member method ET2|+<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|+::T%> /* = self::ET2|+::T% */ #this, self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */ t) → self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */
+  ;
+static inline-class-member method ET2|unary-<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|unary-::T%> /* = self::ET2|unary-::T% */ #this) → self::ET2|unary-::T%
+  ;
+static inline-class-member method ET2|[]<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]::T%> /* = self::ET2|[]::T% */ #this, core::int index) → self::ET2|[]::T%
+  ;
+static inline-class-member method ET2|[]=<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]=::T%> /* = self::ET2|[]=::T% */ #this, core::int index, self::ET2|[]=::T% value) → void
+  ;
+static inline-class-member method ET2|foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|foo::T%> /* = self::ET2|foo::T% */ #this, self::ET2|foo::T% t) → void
+  ;
+static inline-class-member method ET2|get#foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#foo::T%>% /* = self::ET2|get#foo::T% */ #this) → (self::ET2|get#foo::T%) → void
+  return (self::ET2|get#foo::T% t) → void => self::ET2|foo<self::ET2|get#foo::T%>(#this, t);
+static inline-class-member method ET2|get#getter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#getter::T%> /* = self::ET2|get#getter::T% */ #this) → self::ET2|get#getter::T%
+  ;
+static inline-class-member method ET2|set#setter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|set#setter::T%> /* = self::ET2|set#setter::T% */ #this, self::ET2|set#setter::T% value) → void
+  ;
+static method method1(self::ET1 /* = core::int */ et) → dynamic
+  ;
+static method method2(self::ET1? /* = core::int? */ et) → dynamic
+  ;
+static method method3<S extends core::Object? = dynamic>(self::method3::S% s, self::ET2<self::method3::S%> /* = self::method3::S% */ et) → dynamic
+  ;
+static method method4<S extends core::Object? = dynamic>(self::method4::S% s, self::ET2<self::method4::S%>? /* = self::method4::S? */ et) → dynamic
+  ;
+static method method5<S extends core::Object? = dynamic, U extends self::ET2<self::method5::S%> /* = self::method5::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method5::S% s, self::method5::U% et) → dynamic
+  ;
+static method method6<S extends core::Object? = dynamic, U extends self::ET2<self::method6::S%> /* = self::method6::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method6::S% s, self::method6::U? et) → dynamic
+  ;
+static method method7<S extends core::Object? = dynamic, U extends self::ET2<self::method7::S%> /* = self::method7::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method7::U% = self::ET2<dynamic> /* = dynamic */>(self::method7::S% s, self::method7::V% et) → dynamic
+  ;
+static method method8<S extends core::Object? = dynamic, U extends self::ET2<self::method8::S%> /* = self::method8::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method8::U% = self::ET2<dynamic> /* = dynamic */>(self::method8::S% s, self::method8::V? et) → dynamic
+  ;
+static method method9<S extends core::Object? = dynamic, U extends self::ET2<self::method9::S%> /* = self::method9::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method9::U? = self::ET2<dynamic>? /* = dynamic */>(self::method9::S% s, self::method9::V% et) → dynamic
+  ;
+static method method10<S extends core::Object? = dynamic, U extends self::ET2<self::method10::S%>? /* = self::method10::S? */ = self::ET2<dynamic>? /* = dynamic */, V extends self::method10::U% = self::ET2<dynamic>? /* = dynamic */>(self::method10::S% s, self::method10::V% et) → dynamic
+  ;

pkg/front_end/testcases/extension_types/not_non_nullable_access.dart.weak.transformed.expect

@@ -0,0 +1,497 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(0); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+//   et[0] = 0; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+// Try calling using ?. instead.
+//   et.foo(s); // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.foo; // Error
+//      ^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.getter; // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+// Try accessing using ?. instead.
+//   et.setter = // Error
+//      ^^^^^^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+//   et + et; // Error
+//      ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+//   -et; // Error
+//   ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+//   et[0]; // Error
+//     ^
+//
+// pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+//   et[0] = s; // Error
+//     ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type ET1(core::int i) {
+  abstract inline-class-member representation-field get i() → core::int;
+  operator + = self::ET1|+;
+  operator unary- = self::ET1|unary-;
+  operator [] = self::ET1|[];
+  operator []= = self::ET1|[]=;
+  method foo = self::ET1|foo;
+  method tearoff foo = self::ET1|get#foo;
+  get getter = self::ET1|get#getter;
+  set setter = self::ET1|set#setter;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2<T extends core::Object? = dynamic>(T% t) {
+  abstract inline-class-member representation-field get t() → T%;
+  operator + = self::ET2|+;
+  operator unary- = self::ET2|unary-;
+  operator [] = self::ET2|[];
+  operator []= = self::ET2|[]=;
+  method foo = self::ET2|foo;
+  method tearoff foo = self::ET2|get#foo;
+  get getter = self::ET2|get#getter;
+  set setter = self::ET2|set#setter;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static inline-class-member method ET1|constructor#(core::int i) → self::ET1 /* = core::int */ {
+  lowered final self::ET1 /* = core::int */ #this = i;
+  return #this;
+}
+static inline-class-member method ET1|constructor#_#new#tearOff(core::int i) → self::ET1 /* = core::int */
+  return self::ET1|constructor#(i);
+static inline-class-member method ET1|+(lowered final self::ET1 /* = core::int */ #this, self::ET1? /* = core::int? */ i) → self::ET1? /* = core::int? */
+  return i;
+static inline-class-member method ET1|unary-(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[](lowered final self::ET1 /* = core::int */ #this, core::int index) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|[]=(lowered final self::ET1 /* = core::int */ #this, core::int index, core::int value) → void {}
+static inline-class-member method ET1|foo(lowered final self::ET1 /* = core::int */ #this, core::int i) → void {}
+static inline-class-member method ET1|get#foo(lowered final self::ET1 /* = core::int */ #this) → (core::int) → void
+  return (core::int i) → void => self::ET1|foo(#this, i);
+static inline-class-member method ET1|get#getter(lowered final self::ET1 /* = core::int */ #this) → core::int
+  return #this as{Unchecked} core::int;
+static inline-class-member method ET1|set#setter(lowered final self::ET1 /* = core::int */ #this, core::int value) → void {}
+static inline-class-member method ET2|constructor#<T extends core::Object? = dynamic>(self::ET2|constructor#::T% t) → self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ {
+  lowered final self::ET2<self::ET2|constructor#::T%> /* = self::ET2|constructor#::T% */ #this = t;
+  return #this;
+}
+static inline-class-member method ET2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::ET2|constructor#_#new#tearOff::T% t) → self::ET2<self::ET2|constructor#_#new#tearOff::T%>% /* = self::ET2|constructor#_#new#tearOff::T% */
+  return self::ET2|constructor#<self::ET2|constructor#_#new#tearOff::T%>(t);
+static inline-class-member method ET2|+<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|+::T%> /* = self::ET2|+::T% */ #this, self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */ t) → self::ET2<self::ET2|+::T%>? /* = self::ET2|+::T? */
+  return t;
+static inline-class-member method ET2|unary-<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|unary-::T%> /* = self::ET2|unary-::T% */ #this) → self::ET2|unary-::T%
+  return #this as{Unchecked} self::ET2|unary-::T%;
+static inline-class-member method ET2|[]<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]::T%> /* = self::ET2|[]::T% */ #this, core::int index) → self::ET2|[]::T%
+  return #this as{Unchecked} self::ET2|[]::T%;
+static inline-class-member method ET2|[]=<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|[]=::T%> /* = self::ET2|[]=::T% */ #this, core::int index, self::ET2|[]=::T% value) → void {}
+static inline-class-member method ET2|foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|foo::T%> /* = self::ET2|foo::T% */ #this, self::ET2|foo::T% t) → void {}
+static inline-class-member method ET2|get#foo<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#foo::T%>% /* = self::ET2|get#foo::T% */ #this) → (self::ET2|get#foo::T%) → void
+  return (self::ET2|get#foo::T% t) → void => self::ET2|foo<self::ET2|get#foo::T%>(#this, t);
+static inline-class-member method ET2|get#getter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|get#getter::T%> /* = self::ET2|get#getter::T% */ #this) → self::ET2|get#getter::T%
+  return #this as{Unchecked} self::ET2|get#getter::T%;
+static inline-class-member method ET2|set#setter<T extends core::Object? = dynamic>(lowered final self::ET2<self::ET2|set#setter::T%> /* = self::ET2|set#setter::T% */ #this, self::ET2|set#setter::T% value) → void {}
+static method method1(self::ET1 /* = core::int */ et) → dynamic {
+  self::ET1|foo(et, 0);
+  self::ET1|get#foo(et);
+  self::ET1|set#setter(et, self::ET1|get#getter(et));
+  self::ET1|+(et, et);
+  self::ET1|unary-(et);
+  self::ET1|[](et, 0);
+  self::ET1|[]=(et, 0, 0);
+}
+static method method2(self::ET1? /* = core::int? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:36:6: Error: Method 'foo' cannot be called on 'ET1?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(0); // Error
+     ^^^" in self::ET1|foo(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:37:6: Error: Property 'foo' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET1|get#foo(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:38:6: Error: Property 'setter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET1|set#setter(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:39:6: Error: Property 'getter' cannot be accessed on 'ET1?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET1|get#getter(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:40:6: Error: Operator '+' cannot be called on 'ET1?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET1|+(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:41:3: Error: Operator 'unary-' cannot be called on 'ET1?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET1|unary-(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:42:5: Error: Operator '[]' cannot be called on 'ET1?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET1|[](et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:43:5: Error: Operator '[]=' cannot be called on 'ET1?' because it is potentially null.
+  et[0] = 0; // Error
+    ^" in self::ET1|[]=(et, 0, 0);
+}
+static method method3<S extends core::Object? = dynamic>(self::method3::S% s, self::ET2<self::method3::S%> /* = self::method3::S% */ et) → dynamic {
+  self::ET2|foo<self::method3::S%>(et, s);
+  self::ET2|get#foo<self::method3::S%>(et);
+  self::ET2|set#setter<self::method3::S%>(et, self::ET2|get#getter<self::method3::S%>(et));
+  self::ET2|+<self::method3::S%>(et, et);
+  self::ET2|unary-<self::method3::S%>(et);
+  self::ET2|[]<self::method3::S%>(et, 0);
+  self::ET2|[]=<self::method3::S%>(et, 0, s);
+}
+static method method4<S extends core::Object? = dynamic>(self::method4::S% s, self::ET2<self::method4::S%>? /* = self::method4::S? */ et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:57:6: Error: Method 'foo' cannot be called on 'ET2<S>?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method4::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:58:6: Error: Property 'foo' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:59:6: Error: Property 'setter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method4::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:60:6: Error: Property 'getter' cannot be accessed on 'ET2<S>?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method4::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:61:6: Error: Operator '+' cannot be called on 'ET2<S>?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method4::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:62:3: Error: Operator 'unary-' cannot be called on 'ET2<S>?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method4::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:63:5: Error: Operator '[]' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method4::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:64:5: Error: Operator '[]=' cannot be called on 'ET2<S>?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method4::S%>(et, 0, s);
+}
+static method method5<S extends core::Object? = dynamic, U extends self::ET2<self::method5::S%> /* = self::method5::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method5::S% s, self::method5::U% et) → dynamic {
+  self::ET2|foo<self::method5::S%>(et, s);
+  self::ET2|get#foo<self::method5::S%>(et);
+  self::ET2|set#setter<self::method5::S%>(et, self::ET2|get#getter<self::method5::S%>(et));
+  self::ET2|+<self::method5::S%>(et, et);
+  self::ET2|unary-<self::method5::S%>(et);
+  self::ET2|[]<self::method5::S%>(et, 0);
+  self::ET2|[]=<self::method5::S%>(et, 0, s);
+}
+static method method6<S extends core::Object? = dynamic, U extends self::ET2<self::method6::S%> /* = self::method6::S% */ = self::ET2<dynamic> /* = dynamic */>(self::method6::S% s, self::method6::U? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:78:6: Error: Method 'foo' cannot be called on 'U?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method6::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:79:6: Error: Property 'foo' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:80:6: Error: Property 'setter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method6::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:81:6: Error: Property 'getter' cannot be accessed on 'U?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method6::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:82:6: Error: Operator '+' cannot be called on 'U?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method6::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:83:3: Error: Operator 'unary-' cannot be called on 'U?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method6::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:84:5: Error: Operator '[]' cannot be called on 'U?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method6::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:85:5: Error: Operator '[]=' cannot be called on 'U?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method6::S%>(et, 0, s);
+}
+static method method7<S extends core::Object? = dynamic, U extends self::ET2<self::method7::S%> /* = self::method7::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method7::U% = self::ET2<dynamic> /* = dynamic */>(self::method7::S% s, self::method7::V% et) → dynamic {
+  self::ET2|foo<self::method7::S%>(et, s);
+  self::ET2|get#foo<self::method7::S%>(et);
+  self::ET2|set#setter<self::method7::S%>(et, self::ET2|get#getter<self::method7::S%>(et));
+  self::ET2|+<self::method7::S%>(et, et);
+  self::ET2|unary-<self::method7::S%>(et);
+  self::ET2|[]<self::method7::S%>(et, 0);
+  self::ET2|[]=<self::method7::S%>(et, 0, s);
+}
+static method method8<S extends core::Object? = dynamic, U extends self::ET2<self::method8::S%> /* = self::method8::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method8::U% = self::ET2<dynamic> /* = dynamic */>(self::method8::S% s, self::method8::V? et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:99:6: Error: Method 'foo' cannot be called on 'V?' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method8::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:100:6: Error: Property 'foo' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:101:6: Error: Property 'setter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method8::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:102:6: Error: Property 'getter' cannot be accessed on 'V?' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method8::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:103:6: Error: Operator '+' cannot be called on 'V?' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method8::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:104:3: Error: Operator 'unary-' cannot be called on 'V?' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method8::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:105:5: Error: Operator '[]' cannot be called on 'V?' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method8::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:106:5: Error: Operator '[]=' cannot be called on 'V?' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method8::S%>(et, 0, s);
+}
+static method method9<S extends core::Object? = dynamic, U extends self::ET2<self::method9::S%> /* = self::method9::S% */ = self::ET2<dynamic> /* = dynamic */, V extends self::method9::U? = self::ET2<dynamic>? /* = dynamic */>(self::method9::S% s, self::method9::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:110:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method9::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:111:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:112:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method9::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:113:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method9::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:114:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method9::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:115:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method9::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:116:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method9::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:117:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method9::S%>(et, 0, s);
+}
+static method method10<S extends core::Object? = dynamic, U extends self::ET2<self::method10::S%>? /* = self::method10::S? */ = self::ET2<dynamic>? /* = dynamic */, V extends self::method10::U% = self::ET2<dynamic>? /* = dynamic */>(self::method10::S% s, self::method10::V% et) → dynamic {
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:121:6: Error: Method 'foo' cannot be called on 'V' because it is potentially null.
+Try calling using ?. instead.
+  et.foo(s); // Error
+     ^^^" in self::ET2|foo<self::method10::S%>(et, s);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:122:6: Error: Property 'foo' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.foo; // Error
+     ^^^" in self::ET2|get#foo<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:123:6: Error: Property 'setter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.setter = // Error
+     ^^^^^^" in self::ET2|set#setter<self::method10::S%>(et, invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:124:6: Error: Property 'getter' cannot be accessed on 'V' because it is potentially null.
+Try accessing using ?. instead.
+  et.getter; // Error
+     ^^^^^^" in self::ET2|get#getter<self::method10::S%>(et));
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:125:6: Error: Operator '+' cannot be called on 'V' because it is potentially null.
+  et + et; // Error
+     ^" in self::ET2|+<self::method10::S%>(et, et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:126:3: Error: Operator 'unary-' cannot be called on 'V' because it is potentially null.
+  -et; // Error
+  ^" in self::ET2|unary-<self::method10::S%>(et);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:127:5: Error: Operator '[]' cannot be called on 'V' because it is potentially null.
+  et[0]; // Error
+    ^" in self::ET2|[]<self::method10::S%>(et, 0);
+  invalid-expression "pkg/front_end/testcases/extension_types/not_non_nullable_access.dart:128:5: Error: Operator '[]=' cannot be called on 'V' because it is potentially null.
+  et[0] = s; // Error
+    ^" in self::ET2|[]=<self::method10::S%>(et, 0, s);
+}

pkg/front_end/testcases/extension_types/nullable_access.dart

@@ -0,0 +1,20 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by b
+// BSD-style license that can be found in the LICENSE file.
+
+extension E on ET? {
+  void foo(int i) {}
+}
+
+extension type ET(int? i) {
+  void foo() {}
+}
+
+method<X extends ET, Y extends ET?>(ET et1, ET? et2, X x1, X? x2, Y y1, Y? y2) {
+  et1.foo();
+  et2.foo(0);
+  x1.foo();
+  x2.foo(0);
+  y1.foo(0);
+  y2.foo(0);
+}

pkg/front_end/testcases/extension_types/nullable_access.dart.strong.expect

@@ -0,0 +1,35 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+extension E on self::ET? /* = core::int? */ {
+  method foo = self::E|foo;
+  method tearoff foo = self::E|get#foo;
+}
+extension type ET(core::int? i) {
+  abstract inline-class-member representation-field get i() → core::int?;
+  method foo = self::ET|foo;
+  method tearoff foo = self::ET|get#foo;
+  constructor • = self::ET|constructor#;
+  constructor tearoff • = self::ET|constructor#_#new#tearOff;
+}
+static extension-member method E|foo(lowered final self::ET? /* = core::int? */ #this, core::int i) → void {}
+static extension-member method E|get#foo(lowered final self::ET? /* = core::int? */ #this) → (core::int) → void
+  return (core::int i) → void => self::E|foo(#this, i);
+static inline-class-member method ET|constructor#(core::int? i) → self::ET /* = core::int? */ {
+  lowered final self::ET /* = core::int? */ #this = i;
+  return #this;
+}
+static inline-class-member method ET|constructor#_#new#tearOff(core::int? i) → self::ET /* = core::int? */
+  return self::ET|constructor#(i);
+static inline-class-member method ET|foo(lowered final self::ET /* = core::int? */ #this) → void {}
+static inline-class-member method ET|get#foo(lowered final self::ET /* = core::int? */ #this) → () → void
+  return () → void => self::ET|foo(#this);
+static method method<X extends self::ET /* = core::int? */, Y extends self::ET? /* = core::int? */>(self::ET /* = core::int? */ et1, self::ET? /* = core::int? */ et2, self::method::X% x1, self::method::X? x2, self::method::Y% y1, self::method::Y? y2) → dynamic {
+  self::ET|foo(et1);
+  self::E|foo(et2, 0);
+  self::ET|foo(x1);
+  self::E|foo(x2, 0);
+  self::E|foo(y1, 0);
+  self::E|foo(y2, 0);
+}

pkg/front_end/testcases/extension_types/nullable_access.dart.strong.transformed.expect

@@ -0,0 +1,35 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+extension E on self::ET? /* = core::int? */ {
+  method foo = self::E|foo;
+  method tearoff foo = self::E|get#foo;
+}
+extension type ET(core::int? i) {
+  abstract inline-class-member representation-field get i() → core::int?;
+  method foo = self::ET|foo;
+  method tearoff foo = self::ET|get#foo;
+  constructor • = self::ET|constructor#;
+  constructor tearoff • = self::ET|constructor#_#new#tearOff;
+}
+static extension-member method E|foo(lowered final self::ET? /* = core::int? */ #this, core::int i) → void {}
+static extension-member method E|get#foo(lowered final self::ET? /* = core::int? */ #this) → (core::int) → void
+  return (core::int i) → void => self::E|foo(#this, i);
+static inline-class-member method ET|constructor#(core::int? i) → self::ET /* = core::int? */ {
+  lowered final self::ET /* = core::int? */ #this = i;
+  return #this;
+}
+static inline-class-member method ET|constructor#_#new#tearOff(core::int? i) → self::ET /* = core::int? */
+  return self::ET|constructor#(i);
+static inline-class-member method ET|foo(lowered final self::ET /* = core::int? */ #this) → void {}
+static inline-class-member method ET|get#foo(lowered final self::ET /* = core::int? */ #this) → () → void
+  return () → void => self::ET|foo(#this);
+static method method<X extends self::ET /* = core::int? */, Y extends self::ET? /* = core::int? */>(self::ET /* = core::int? */ et1, self::ET? /* = core::int? */ et2, self::method::X% x1, self::method::X? x2, self::method::Y% y1, self::method::Y? y2) → dynamic {
+  self::ET|foo(et1);
+  self::E|foo(et2, 0);
+  self::ET|foo(x1);
+  self::E|foo(x2, 0);
+  self::E|foo(y1, 0);
+  self::E|foo(y2, 0);
+}

pkg/front_end/testcases/extension_types/nullable_access.dart.textual_outline.expect

@@ -0,0 +1,7 @@
+extension E on ET? {
+  void foo(int i) {}
+}
+extension type ET(int? i) {
+  void foo() {}
+}
+method<X extends ET, Y extends ET?>(ET et1, ET? et2, X x1, X? x2, Y y1, Y? y2) {}

pkg/front_end/testcases/extension_types/nullable_access.dart.textual_outline_modelled.expect

@@ -0,0 +1,7 @@
+extension E on ET? {
+  void foo(int i) {}
+}
+extension type ET(int? i) {
+  void foo() {}
+}
+method<X extends ET, Y extends ET?>(ET et1, ET? et2, X x1, X? x2, Y y1, Y? y2) {}

pkg/front_end/testcases/extension_types/nullable_access.dart.weak.expect

@@ -0,0 +1,35 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+extension E on self::ET? /* = core::int? */ {
+  method foo = self::E|foo;
+  method tearoff foo = self::E|get#foo;
+}
+extension type ET(core::int? i) {
+  abstract inline-class-member representation-field get i() → core::int?;
+  method foo = self::ET|foo;
+  method tearoff foo = self::ET|get#foo;
+  constructor • = self::ET|constructor#;
+  constructor tearoff • = self::ET|constructor#_#new#tearOff;
+}
+static extension-member method E|foo(lowered final self::ET? /* = core::int? */ #this, core::int i) → void {}
+static extension-member method E|get#foo(lowered final self::ET? /* = core::int? */ #this) → (core::int) → void
+  return (core::int i) → void => self::E|foo(#this, i);
+static inline-class-member method ET|constructor#(core::int? i) → self::ET /* = core::int? */ {
+  lowered final self::ET /* = core::int? */ #this = i;
+  return #this;
+}
+static inline-class-member method ET|constructor#_#new#tearOff(core::int? i) → self::ET /* = core::int? */
+  return self::ET|constructor#(i);
+static inline-class-member method ET|foo(lowered final self::ET /* = core::int? */ #this) → void {}
+static inline-class-member method ET|get#foo(lowered final self::ET /* = core::int? */ #this) → () → void
+  return () → void => self::ET|foo(#this);
+static method method<X extends self::ET /* = core::int? */, Y extends self::ET? /* = core::int? */>(self::ET /* = core::int? */ et1, self::ET? /* = core::int? */ et2, self::method::X% x1, self::method::X? x2, self::method::Y% y1, self::method::Y? y2) → dynamic {
+  self::ET|foo(et1);
+  self::E|foo(et2, 0);
+  self::ET|foo(x1);
+  self::E|foo(x2, 0);
+  self::E|foo(y1, 0);
+  self::E|foo(y2, 0);
+}

pkg/front_end/testcases/extension_types/nullable_access.dart.weak.modular.expect

@@ -0,0 +1,35 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+extension E on self::ET? /* = core::int? */ {
+  method foo = self::E|foo;
+  method tearoff foo = self::E|get#foo;
+}
+extension type ET(core::int? i) {
+  abstract inline-class-member representation-field get i() → core::int?;
+  method foo = self::ET|foo;
+  method tearoff foo = self::ET|get#foo;
+  constructor • = self::ET|constructor#;
+  constructor tearoff • = self::ET|constructor#_#new#tearOff;
+}
+static extension-member method E|foo(lowered final self::ET? /* = core::int? */ #this, core::int i) → void {}
+static extension-member method E|get#foo(lowered final self::ET? /* = core::int? */ #this) → (core::int) → void
+  return (core::int i) → void => self::E|foo(#this, i);
+static inline-class-member method ET|constructor#(core::int? i) → self::ET /* = core::int? */ {
+  lowered final self::ET /* = core::int? */ #this = i;
+  return #this;
+}
+static inline-class-member method ET|constructor#_#new#tearOff(core::int? i) → self::ET /* = core::int? */
+  return self::ET|constructor#(i);
+static inline-class-member method ET|foo(lowered final self::ET /* = core::int? */ #this) → void {}
+static inline-class-member method ET|get#foo(lowered final self::ET /* = core::int? */ #this) → () → void
+  return () → void => self::ET|foo(#this);
+static method method<X extends self::ET /* = core::int? */, Y extends self::ET? /* = core::int? */>(self::ET /* = core::int? */ et1, self::ET? /* = core::int? */ et2, self::method::X% x1, self::method::X? x2, self::method::Y% y1, self::method::Y? y2) → dynamic {
+  self::ET|foo(et1);
+  self::E|foo(et2, 0);
+  self::ET|foo(x1);
+  self::E|foo(x2, 0);
+  self::E|foo(y1, 0);
+  self::E|foo(y2, 0);
+}

pkg/front_end/testcases/extension_types/nullable_access.dart.weak.outline.expect

@@ -0,0 +1,29 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+extension E on self::ET? /* = core::int? */ {
+  method foo = self::E|foo;
+  method tearoff foo = self::E|get#foo;
+}
+extension type ET(core::int? i) {
+  abstract inline-class-member representation-field get i() → core::int?;
+  method foo = self::ET|foo;
+  method tearoff foo = self::ET|get#foo;
+  constructor • = self::ET|constructor#;
+  constructor tearoff • = self::ET|constructor#_#new#tearOff;
+}
+static extension-member method E|foo(lowered final self::ET? /* = core::int? */ #this, core::int i) → void
+  ;
+static extension-member method E|get#foo(lowered final self::ET? /* = core::int? */ #this) → (core::int) → void
+  return (core::int i) → void => self::E|foo(#this, i);
+static inline-class-member method ET|constructor#(core::int? i) → self::ET /* = core::int? */
+  ;
+static inline-class-member method ET|constructor#_#new#tearOff(core::int? i) → self::ET /* = core::int? */
+  return self::ET|constructor#(i);
+static inline-class-member method ET|foo(lowered final self::ET /* = core::int? */ #this) → void
+  ;
+static inline-class-member method ET|get#foo(lowered final self::ET /* = core::int? */ #this) → () → void
+  return () → void => self::ET|foo(#this);
+static method method<X extends self::ET /* = core::int? */, Y extends self::ET? /* = core::int? */>(self::ET /* = core::int? */ et1, self::ET? /* = core::int? */ et2, self::method::X% x1, self::method::X? x2, self::method::Y% y1, self::method::Y? y2) → dynamic
+  ;

pkg/front_end/testcases/extension_types/nullable_access.dart.weak.transformed.expect

@@ -0,0 +1,35 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+extension E on self::ET? /* = core::int? */ {
+  method foo = self::E|foo;
+  method tearoff foo = self::E|get#foo;
+}
+extension type ET(core::int? i) {
+  abstract inline-class-member representation-field get i() → core::int?;
+  method foo = self::ET|foo;
+  method tearoff foo = self::ET|get#foo;
+  constructor • = self::ET|constructor#;
+  constructor tearoff • = self::ET|constructor#_#new#tearOff;
+}
+static extension-member method E|foo(lowered final self::ET? /* = core::int? */ #this, core::int i) → void {}
+static extension-member method E|get#foo(lowered final self::ET? /* = core::int? */ #this) → (core::int) → void
+  return (core::int i) → void => self::E|foo(#this, i);
+static inline-class-member method ET|constructor#(core::int? i) → self::ET /* = core::int? */ {
+  lowered final self::ET /* = core::int? */ #this = i;
+  return #this;
+}
+static inline-class-member method ET|constructor#_#new#tearOff(core::int? i) → self::ET /* = core::int? */
+  return self::ET|constructor#(i);
+static inline-class-member method ET|foo(lowered final self::ET /* = core::int? */ #this) → void {}
+static inline-class-member method ET|get#foo(lowered final self::ET /* = core::int? */ #this) → () → void
+  return () → void => self::ET|foo(#this);
+static method method<X extends self::ET /* = core::int? */, Y extends self::ET? /* = core::int? */>(self::ET /* = core::int? */ et1, self::ET? /* = core::int? */ et2, self::method::X% x1, self::method::X? x2, self::method::Y% y1, self::method::Y? y2) → dynamic {
+  self::ET|foo(et1);
+  self::E|foo(et2, 0);
+  self::ET|foo(x1);
+  self::E|foo(x2, 0);
+  self::E|foo(y1, 0);
+  self::E|foo(y2, 0);
+}

pkg/front_end/testcases/extension_types/procedures.dart.strong.expect

@@ -1,37 +1,4 @@
 library;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localM = instanceMethod();
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localT = instanceMethod;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localG = instanceGetter;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG1 = genericInstanceMethod(s);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG2 = genericInstanceMethod(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG3 = genericInstanceMethod<num>(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
 import self as self;
 import "dart:core" as core;
 
@@ -109,18 +76,9 @@ static inline-class-member method GenericClass|constructor#_#_#tearOff<T extends
   return self::GenericClass|constructor#_<self::GenericClass|constructor#_#_#tearOff::T%>(it);
 static inline-class-member method GenericClass|instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ #this) → void {
   self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ local = #this;
-  void localM = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localM = instanceMethod();
-                 ^^^^^^^^^^^^^^" in self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  () → void localT = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localT = instanceMethod;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  self::GenericClass|instanceMethod::T% localG = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localG = instanceGetter;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
+  void localM = self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  () → void localT = self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  self::GenericClass|instanceMethod::T% localG = self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
 }
 static inline-class-member method GenericClass|get#instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod::T%>% /* = self::GenericClass|get#instanceMethod::T% */ #this) → () → void
   return () → void => self::GenericClass|instanceMethod<self::GenericClass|get#instanceMethod::T%>(#this);
@@ -130,18 +88,9 @@ static inline-class-member method GenericClass|instanceMethod2<T extends core::O
   self::GenericClass<self::GenericClass|instanceMethod2::T%> /* = self::GenericClass|instanceMethod2::T% */ local = #this;
   core::String localS = s;
   core::int localI = i;
-  core::String localG1 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG1 = genericInstanceMethod(s);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
-  core::int localG2 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG2 = genericInstanceMethod(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
-  core::num localG3 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG3 = genericInstanceMethod<num>(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
+  core::String localG1 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
+  core::int localG2 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
+  core::num localG3 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
 }
 static inline-class-member method GenericClass|get#instanceMethod2<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod2::T%>% /* = self::GenericClass|get#instanceMethod2::T% */ #this) → (core::String, {i: core::int}) → void
   return (core::String s, {core::int i = #C1}) → void => self::GenericClass|instanceMethod2<self::GenericClass|get#instanceMethod2::T%>(#this, s, i: i);

pkg/front_end/testcases/extension_types/procedures.dart.strong.transformed.expect

@@ -1,37 +1,4 @@
 library;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localM = instanceMethod();
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localT = instanceMethod;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localG = instanceGetter;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG1 = genericInstanceMethod(s);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG2 = genericInstanceMethod(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG3 = genericInstanceMethod<num>(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
 import self as self;
 import "dart:core" as core;
 
@@ -109,18 +76,9 @@ static inline-class-member method GenericClass|constructor#_#_#tearOff<T extends
   return self::GenericClass|constructor#_<self::GenericClass|constructor#_#_#tearOff::T%>(it);
 static inline-class-member method GenericClass|instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ #this) → void {
   self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ local = #this;
-  void localM = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localM = instanceMethod();
-                 ^^^^^^^^^^^^^^" in self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  () → void localT = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localT = instanceMethod;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  self::GenericClass|instanceMethod::T% localG = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localG = instanceGetter;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
+  void localM = self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  () → void localT = self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  self::GenericClass|instanceMethod::T% localG = self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
 }
 static inline-class-member method GenericClass|get#instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod::T%>% /* = self::GenericClass|get#instanceMethod::T% */ #this) → () → void
   return () → void => self::GenericClass|instanceMethod<self::GenericClass|get#instanceMethod::T%>(#this);
@@ -130,18 +88,9 @@ static inline-class-member method GenericClass|instanceMethod2<T extends core::O
   self::GenericClass<self::GenericClass|instanceMethod2::T%> /* = self::GenericClass|instanceMethod2::T% */ local = #this;
   core::String localS = s;
   core::int localI = i;
-  core::String localG1 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG1 = genericInstanceMethod(s);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
-  core::int localG2 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG2 = genericInstanceMethod(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
-  core::num localG3 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG3 = genericInstanceMethod<num>(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
+  core::String localG1 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
+  core::int localG2 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
+  core::num localG3 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
 }
 static inline-class-member method GenericClass|get#instanceMethod2<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod2::T%>% /* = self::GenericClass|get#instanceMethod2::T% */ #this) → (core::String, {i: core::int}) → void
   return (core::String s, {core::int i = #C1}) → void => self::GenericClass|instanceMethod2<self::GenericClass|get#instanceMethod2::T%>(#this, s, i: i);

pkg/front_end/testcases/extension_types/procedures.dart.weak.expect

@@ -1,37 +1,4 @@
 library;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localM = instanceMethod();
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localT = instanceMethod;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localG = instanceGetter;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG1 = genericInstanceMethod(s);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG2 = genericInstanceMethod(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG3 = genericInstanceMethod<num>(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
 import self as self;
 import "dart:core" as core;
 
@@ -109,18 +76,9 @@ static inline-class-member method GenericClass|constructor#_#_#tearOff<T extends
   return self::GenericClass|constructor#_<self::GenericClass|constructor#_#_#tearOff::T%>(it);
 static inline-class-member method GenericClass|instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ #this) → void {
   self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ local = #this;
-  void localM = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localM = instanceMethod();
-                 ^^^^^^^^^^^^^^" in self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  () → void localT = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localT = instanceMethod;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  self::GenericClass|instanceMethod::T% localG = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localG = instanceGetter;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
+  void localM = self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  () → void localT = self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  self::GenericClass|instanceMethod::T% localG = self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
 }
 static inline-class-member method GenericClass|get#instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod::T%>% /* = self::GenericClass|get#instanceMethod::T% */ #this) → () → void
   return () → void => self::GenericClass|instanceMethod<self::GenericClass|get#instanceMethod::T%>(#this);
@@ -130,18 +88,9 @@ static inline-class-member method GenericClass|instanceMethod2<T extends core::O
   self::GenericClass<self::GenericClass|instanceMethod2::T%> /* = self::GenericClass|instanceMethod2::T% */ local = #this;
   core::String localS = s;
   core::int localI = i;
-  core::String localG1 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG1 = genericInstanceMethod(s);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
-  core::int localG2 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG2 = genericInstanceMethod(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
-  core::num localG3 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG3 = genericInstanceMethod<num>(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
+  core::String localG1 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
+  core::int localG2 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
+  core::num localG3 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
 }
 static inline-class-member method GenericClass|get#instanceMethod2<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod2::T%>% /* = self::GenericClass|get#instanceMethod2::T% */ #this) → (core::String, {i: core::int}) → void
   return (core::String s, {core::int i = #C1}) → void => self::GenericClass|instanceMethod2<self::GenericClass|get#instanceMethod2::T%>(#this, s, i: i);

pkg/front_end/testcases/extension_types/procedures.dart.weak.modular.expect

@@ -1,37 +1,4 @@
 library;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localM = instanceMethod();
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localT = instanceMethod;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localG = instanceGetter;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG1 = genericInstanceMethod(s);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG2 = genericInstanceMethod(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG3 = genericInstanceMethod<num>(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
 import self as self;
 import "dart:core" as core;
 
@@ -109,18 +76,9 @@ static inline-class-member method GenericClass|constructor#_#_#tearOff<T extends
   return self::GenericClass|constructor#_<self::GenericClass|constructor#_#_#tearOff::T%>(it);
 static inline-class-member method GenericClass|instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ #this) → void {
   self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ local = #this;
-  void localM = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localM = instanceMethod();
-                 ^^^^^^^^^^^^^^" in self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  () → void localT = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localT = instanceMethod;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  self::GenericClass|instanceMethod::T% localG = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localG = instanceGetter;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
+  void localM = self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  () → void localT = self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  self::GenericClass|instanceMethod::T% localG = self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
 }
 static inline-class-member method GenericClass|get#instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod::T%>% /* = self::GenericClass|get#instanceMethod::T% */ #this) → () → void
   return () → void => self::GenericClass|instanceMethod<self::GenericClass|get#instanceMethod::T%>(#this);
@@ -130,18 +88,9 @@ static inline-class-member method GenericClass|instanceMethod2<T extends core::O
   self::GenericClass<self::GenericClass|instanceMethod2::T%> /* = self::GenericClass|instanceMethod2::T% */ local = #this;
   core::String localS = s;
   core::int localI = i;
-  core::String localG1 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG1 = genericInstanceMethod(s);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
-  core::int localG2 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG2 = genericInstanceMethod(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
-  core::num localG3 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG3 = genericInstanceMethod<num>(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
+  core::String localG1 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
+  core::int localG2 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
+  core::num localG3 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
 }
 static inline-class-member method GenericClass|get#instanceMethod2<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod2::T%>% /* = self::GenericClass|get#instanceMethod2::T% */ #this) → (core::String, {i: core::int}) → void
   return (core::String s, {core::int i = #C1}) → void => self::GenericClass|instanceMethod2<self::GenericClass|get#instanceMethod2::T%>(#this, s, i: i);

pkg/front_end/testcases/extension_types/procedures.dart.weak.transformed.expect

@@ -1,37 +1,4 @@
 library;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localM = instanceMethod();
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localT = instanceMethod;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-// Try accessing using ?. instead.
-//     var localG = instanceGetter;
-//                  ^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG1 = genericInstanceMethod(s);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG2 = genericInstanceMethod(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-// Try calling using ?. instead.
-//     var localG3 = genericInstanceMethod<num>(i);
-//                   ^^^^^^^^^^^^^^^^^^^^^
-//
 import self as self;
 import "dart:core" as core;
 
@@ -109,18 +76,9 @@ static inline-class-member method GenericClass|constructor#_#_#tearOff<T extends
   return self::GenericClass|constructor#_<self::GenericClass|constructor#_#_#tearOff::T%>(it);
 static inline-class-member method GenericClass|instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ #this) → void {
   self::GenericClass<self::GenericClass|instanceMethod::T%> /* = self::GenericClass|instanceMethod::T% */ local = #this;
-  void localM = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:39:18: Error: Method 'instanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localM = instanceMethod();
-                 ^^^^^^^^^^^^^^" in self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  () → void localT = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:40:18: Error: Property 'instanceMethod' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localT = instanceMethod;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
-  self::GenericClass|instanceMethod::T% localG = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:41:18: Error: Property 'instanceGetter' cannot be accessed on 'GenericClass<T>' because it is potentially null.
-Try accessing using ?. instead.
-    var localG = instanceGetter;
-                 ^^^^^^^^^^^^^^" in self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
+  void localM = self::GenericClass|instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  () → void localT = self::GenericClass|get#instanceMethod<self::GenericClass|instanceMethod::T%>(#this);
+  self::GenericClass|instanceMethod::T% localG = self::GenericClass|get#instanceGetter<self::GenericClass|instanceMethod::T%>(#this);
 }
 static inline-class-member method GenericClass|get#instanceMethod<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod::T%>% /* = self::GenericClass|get#instanceMethod::T% */ #this) → () → void
   return () → void => self::GenericClass|instanceMethod<self::GenericClass|get#instanceMethod::T%>(#this);
@@ -130,18 +88,9 @@ static inline-class-member method GenericClass|instanceMethod2<T extends core::O
   self::GenericClass<self::GenericClass|instanceMethod2::T%> /* = self::GenericClass|instanceMethod2::T% */ local = #this;
   core::String localS = s;
   core::int localI = i;
-  core::String localG1 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:50:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG1 = genericInstanceMethod(s);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
-  core::int localG2 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:51:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG2 = genericInstanceMethod(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
-  core::num localG3 = invalid-expression "pkg/front_end/testcases/extension_types/procedures.dart:52:19: Error: Method 'genericInstanceMethod' cannot be called on 'GenericClass<T>' because it is potentially null.
-Try calling using ?. instead.
-    var localG3 = genericInstanceMethod<num>(i);
-                  ^^^^^^^^^^^^^^^^^^^^^" in self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
+  core::String localG1 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::String>(#this, s);
+  core::int localG2 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::int>(#this, i);
+  core::num localG3 = self::GenericClass|genericInstanceMethod<self::GenericClass|instanceMethod2::T%, core::num>(#this, i);
 }
 static inline-class-member method GenericClass|get#instanceMethod2<T extends core::Object? = dynamic>(lowered final self::GenericClass<self::GenericClass|get#instanceMethod2::T%>% /* = self::GenericClass|get#instanceMethod2::T% */ #this) → (core::String, {i: core::int}) → void
   return (core::String s, {core::int i = #C1}) → void => self::GenericClass|instanceMethod2<self::GenericClass|get#instanceMethod2::T%>(#this, s, i: i);

pkg/kernel/lib/ast.dart

@@ -4040,7 +4040,7 @@ sealed class Expression extends TreeNode {
       return context.typeEnvironment.coreTypes
           .rawType(superclass, context.nonNullable);
     }
-    DartType type = getStaticType(context).resolveTypeParameterType;
+    DartType type = getStaticType(context).nonTypeVariableBound;
     if (type is NullType) {
       return context.typeEnvironment.coreTypes
           .bottomInterfaceType(superclass, context.nullable);
@@ -9798,7 +9798,7 @@ class ForInStatement extends Statement {
   /// type of this for-in statement is not already cached in [context].
   DartType getElementTypeInternal(StaticTypeContext context) {
     DartType iterableType =
-        iterable.getStaticType(context).resolveTypeParameterType;
+        iterable.getStaticType(context).nonTypeVariableBound;
     // TODO(johnniwinther): Update this to use the type of
     //  `iterable.iterator.current` if inference is updated accordingly.
     while (iterableType is TypeParameterType) {
@@ -11099,8 +11099,20 @@ sealed class DartType extends Node {
         nullability == Nullability.undetermined;
   }
 
-  /// Returns the non-type parameter type bound of this type.
-  DartType get resolveTypeParameterType;
+  /// Returns the non-type variable bound of this type, taking nullability
+  /// into account.
+  ///
+  /// For instance in
+  ///
+  ///     method<T, S extends Class, U extends S?>()
+  ///
+  /// the non-type variable bound of `T` is `Object?`, for `S` it is `Class`,
+  /// and for `U` it is `Class?`.
+  DartType get nonTypeVariableBound;
+
+  /// Returns `true` if members *not* declared on `Object` can be accessed on
+  /// a receiver of this type.
+  bool get hasNonObjectMemberAccess;
 
   /// Returns the type with all occurrences of [ExtensionType] replaced by their
   /// representations, transitively. This is the type used at runtime to
@@ -11180,7 +11192,10 @@ class InvalidType extends DartType {
   void visitChildren(Visitor v) {}
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => true;
 
   @override
   bool equals(Object other, Assumptions? assumptions) => other is InvalidType;
@@ -11230,7 +11245,10 @@ class DynamicType extends DartType {
   void visitChildren(Visitor v) {}
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => true;
 
   @override
   bool equals(Object other, Assumptions? assumptions) => other is DynamicType;
@@ -11272,7 +11290,10 @@ class VoidType extends DartType {
   void visitChildren(Visitor v) {}
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => false;
 
   @override
   bool equals(Object other, Assumptions? assumptions) => other is VoidType;
@@ -11328,7 +11349,15 @@ class NeverType extends DartType {
   Nullability get nullability => declaredNullability;
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => switch (declaredNullability) {
+        Nullability.undetermined => false,
+        Nullability.nullable => false,
+        Nullability.nonNullable => true,
+        Nullability.legacy => true,
+      };
 
   @override
   int get hashCode {
@@ -11386,7 +11415,10 @@ class NullType extends DartType {
   void visitChildren(Visitor v) {}
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => false;
 
   @override
   bool equals(Object other, Assumptions? assumptions) => other is NullType;
@@ -11439,7 +11471,15 @@ class InterfaceType extends TypeDeclarationType {
   Nullability get nullability => declaredNullability;
 
   @override
-  DartType get resolveTypeParameterType => this;
+  bool get hasNonObjectMemberAccess => switch (declaredNullability) {
+        Nullability.undetermined => false,
+        Nullability.nullable => false,
+        Nullability.nonNullable => true,
+        Nullability.legacy => true,
+      };
+
+  @override
+  DartType get nonTypeVariableBound => this;
 
   static List<DartType> _defaultTypeArguments(Class classNode) {
     if (classNode.typeParameters.length == 0) {
@@ -11542,7 +11582,15 @@ class FunctionType extends DartType {
   Nullability get nullability => declaredNullability;
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => switch (declaredNullability) {
+        Nullability.undetermined => false,
+        Nullability.nullable => false,
+        Nullability.nonNullable => true,
+        Nullability.legacy => true,
+      };
 
   @override
   R accept<R>(DartTypeVisitor<R> v) => v.visitFunctionType(this);
@@ -11741,7 +11789,10 @@ class TypedefType extends DartType {
   Nullability get nullability => declaredNullability;
 
   @override
-  DartType get resolveTypeParameterType => unalias.resolveTypeParameterType;
+  DartType get nonTypeVariableBound => unalias.nonTypeVariableBound;
+
+  @override
+  bool get hasNonObjectMemberAccess => unalias.hasNonObjectMemberAccess;
 
   @override
   R accept<R>(DartTypeVisitor<R> v) => v.visitTypedefType(this);
@@ -11849,7 +11900,10 @@ class FutureOrType extends DartType {
   }
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => false;
 
   @override
   bool equals(Object other, Assumptions? assumptions) {
@@ -11957,7 +12011,17 @@ class ExtensionType extends TypeDeclarationType {
   }
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => switch (declaredNullability) {
+        // Undetermined means that the extension type does not implement
+        // `Object` but is not explicitly marked as nullable.
+        Nullability.undetermined => true,
+        Nullability.nullable => false,
+        Nullability.nonNullable => true,
+        Nullability.legacy => true,
+      };
 
   static List<DartType> _defaultTypeArguments(
       ExtensionTypeDeclaration extensionTypeDeclaration) {
@@ -12201,7 +12265,16 @@ class IntersectionType extends DartType {
   }
 
   @override
-  DartType get resolveTypeParameterType => right.resolveTypeParameterType;
+  DartType get nonTypeVariableBound {
+    DartType resolvedTypeParameterType = right.nonTypeVariableBound;
+    return resolvedTypeParameterType.withDeclaredNullability(
+        combineNullabilitiesForSubstitution(
+            resolvedTypeParameterType.nullability, declaredNullability));
+  }
+
+  @override
+  bool get hasNonObjectMemberAccess =>
+      nonTypeVariableBound.hasNonObjectMemberAccess;
 
   @override
   R accept<R>(DartTypeVisitor<R> v) => v.visitIntersectionType(this);
@@ -12484,7 +12557,16 @@ class TypeParameterType extends DartType {
             : Nullability.legacy;
 
   @override
-  DartType get resolveTypeParameterType => bound.resolveTypeParameterType;
+  DartType get nonTypeVariableBound {
+    DartType resolvedTypeParameterType = bound.nonTypeVariableBound;
+    return resolvedTypeParameterType.withDeclaredNullability(
+        combineNullabilitiesForSubstitution(
+            resolvedTypeParameterType.nullability, declaredNullability));
+  }
+
+  @override
+  bool get hasNonObjectMemberAccess =>
+      nonTypeVariableBound.hasNonObjectMemberAccess;
 
   @override
   R accept<R>(DartTypeVisitor<R> v) => v.visitTypeParameterType(this);
@@ -12639,7 +12721,16 @@ class StructuralParameterType extends DartType {
             : Nullability.legacy;
 
   @override
-  DartType get resolveTypeParameterType => bound.resolveTypeParameterType;
+  DartType get nonTypeVariableBound {
+    DartType resolvedTypeParameterType = bound.nonTypeVariableBound;
+    return resolvedTypeParameterType.withDeclaredNullability(
+        combineNullabilitiesForSubstitution(
+            resolvedTypeParameterType.nullability, declaredNullability));
+  }
+
+  @override
+  bool get hasNonObjectMemberAccess =>
+      nonTypeVariableBound.hasNonObjectMemberAccess;
 
   @override
   R accept<R>(DartTypeVisitor<R> v) => v.visitStructuralParameterType(this);
@@ -12786,7 +12877,15 @@ class RecordType extends DartType {
   Nullability get nullability => declaredNullability;
 
   @override
-  DartType get resolveTypeParameterType => this;
+  DartType get nonTypeVariableBound => this;
+
+  @override
+  bool get hasNonObjectMemberAccess => switch (declaredNullability) {
+        Nullability.undetermined => false,
+        Nullability.nullable => false,
+        Nullability.nonNullable => true,
+        Nullability.legacy => true,
+      };
 
   @override
   R accept<R>(DartTypeVisitor<R> v) {

pkg/kernel/lib/naive_type_checker.dart

@@ -268,7 +268,7 @@ super method declares ${superParameter.type}
 
   @override
   void checkUnresolvedInvocation(DartType receiver, TreeNode where) {
-    receiver = receiver.resolveTypeParameterType;
+    receiver = receiver.nonTypeVariableBound;
 
     if (receiver is DynamicType) {
       return;

pkg/kernel/lib/type_checker.dart

@@ -249,7 +249,7 @@ class TypeCheckingVisitor
       return Substitution.empty; // Members on Object are always accessible.
     }
 
-    type = type.resolveTypeParameterType;
+    type = type.nonTypeVariableBound;
     if (type is NeverType || type is NullType || type is InvalidType) {
       // The bottom type is a subtype of all types, so it should be allowed.
       return Substitution.bottomForTypeDeclaration(typeDeclaration);

pkg/kernel/lib/type_environment.dart

@@ -98,7 +98,7 @@ abstract class TypeEnvironment extends Types {
     //
     // When none of these cases are applicable, we say that T does not have a
     // future type.
-    DartType resolved = t.resolveTypeParameterType;
+    DartType resolved = t.nonTypeVariableBound;
     if (resolved is TypeDeclarationType) {
       DartType? futureType = getTypeAsInstanceOf(
           resolved, coreTypes.futureClass, coreTypes,
@@ -284,8 +284,8 @@ abstract class TypeEnvironment extends Types {
       // Otherwise the static type of e is num.
       return coreTypes.numNonNullableRawType;
     } else {
-      type1 = type1.resolveTypeParameterType;
-      type2 = type2.resolveTypeParameterType;
+      type1 = type1.nonTypeVariableBound;
+      type2 = type2.nonTypeVariableBound;
 
       if (type1 == type2) return type1;