diff --git a/pkg/front_end/lib/src/fragment/constructor/body_builder_context.dart b/pkg/front_end/lib/src/fragment/constructor/body_builder_context.dart
index 85abd61f811..c562610b5d6 100644
--- a/pkg/front_end/lib/src/fragment/constructor/body_builder_context.dart
+++ b/pkg/front_end/lib/src/fragment/constructor/body_builder_context.dart
@@ -152,6 +152,9 @@ class ConstructorBodyBuilderContext extends BodyBuilderContext {
       scopeProviderInfo
           // Coverage-ignore(suite): Not run.
           ?.scope,
+      scopeProviderInfo
+          // Coverage-ignore(suite): Not run.
+          ?.thisVariable,
     );
   }
 
diff --git a/pkg/front_end/lib/src/fragment/constructor/declaration.dart b/pkg/front_end/lib/src/fragment/constructor/declaration.dart
index 4c4c26f1186..b05f037a543 100644
--- a/pkg/front_end/lib/src/fragment/constructor/declaration.dart
+++ b/pkg/front_end/lib/src/fragment/constructor/declaration.dart
@@ -761,8 +761,16 @@ mixin _ConstructorEncodingMixin
   List<TypeParameter>? get thisTypeParameters => _encoding.thisTypeParameters;
 
   @override
-  void registerFunctionBody(Statement? body, Scope? scope) {
-    _encoding.registerFunctionBody(body: body, scope: scope);
+  void registerFunctionBody(
+    Statement? body,
+    Scope? scope,
+    VariableDeclaration? thisVariable,
+  ) {
+    _encoding.registerFunctionBody(
+      body: body,
+      scope: scope,
+      thisVariable: thisVariable,
+    );
   }
 
   @override
@@ -1461,7 +1469,11 @@ abstract class ConstructorFragmentDeclaration {
     SourceConstructorBuilder constructorBuilder,
   );
 
-  void registerFunctionBody(Statement? body, Scope? scope);
+  void registerFunctionBody(
+    Statement? body,
+    Scope? scope,
+    VariableDeclaration? thisVariable,
+  );
 
   void registerNoBodyConstructor();
 
diff --git a/pkg/front_end/lib/src/fragment/constructor/encoding.dart b/pkg/front_end/lib/src/fragment/constructor/encoding.dart
index c53caadfdf0..e4845967ca6 100644
--- a/pkg/front_end/lib/src/fragment/constructor/encoding.dart
+++ b/pkg/front_end/lib/src/fragment/constructor/encoding.dart
@@ -87,7 +87,11 @@ abstract class ConstructorEncoding {
     ConstructorFragmentDeclaration constructorDeclaration,
   );
 
-  void registerFunctionBody({required Statement? body, Scope? scope});
+  void registerFunctionBody({
+    required Statement? body,
+    Scope? scope,
+    VariableDeclaration? thisVariable,
+  });
 
   void registerNoBodyConstructor();
 
@@ -131,11 +135,16 @@ class RegularConstructorEncoding implements ConstructorEncoding {
        _isEnumConstructor = isEnumConstructor;
 
   @override
-  void registerFunctionBody({required Statement? body, Scope? scope}) {
+  void registerFunctionBody({
+    required Statement? body,
+    Scope? scope,
+    VariableDeclaration? thisVariable,
+  }) {
     if (body != null) {
       _constructor.function.registerFunctionBody(body);
     }
     _constructor.function.scope = scope;
+    _constructor.function.thisVariable = thisVariable;
   }
 
   @override
@@ -511,11 +520,16 @@ mixin _ExtensionTypeConstructorEncodingMixin<T extends DeclarationBuilder>
   }
 
   @override
-  void registerFunctionBody({required Statement? body, Scope? scope}) {
+  void registerFunctionBody({
+    required Statement? body,
+    Scope? scope,
+    VariableDeclaration? thisVariable,
+  }) {
     if (body != null) {
       _constructor.function.registerFunctionBody(body);
     }
     _constructor.function.scope = scope;
+    _constructor.function.thisVariable = thisVariable;
   }
 
   @override
diff --git a/pkg/front_end/lib/src/fragment/factory/body_builder_context.dart b/pkg/front_end/lib/src/fragment/factory/body_builder_context.dart
index 5cb364c76dd..968dc00131d 100644
--- a/pkg/front_end/lib/src/fragment/factory/body_builder_context.dart
+++ b/pkg/front_end/lib/src/fragment/factory/body_builder_context.dart
@@ -87,6 +87,9 @@ class FactoryBodyBuilderContext extends BodyBuilderContext {
           ?.scope,
       asyncMarker: asyncMarker,
       emittedValueType: emittedValueType,
+      thisVariable: scopeProviderInfo
+          // Coverage-ignore(suite): Not run.
+          ?.thisVariable,
     );
   }
 
diff --git a/pkg/front_end/lib/src/fragment/factory/declaration.dart b/pkg/front_end/lib/src/fragment/factory/declaration.dart
index b1ac1ae2f20..86c47ede535 100644
--- a/pkg/front_end/lib/src/fragment/factory/declaration.dart
+++ b/pkg/front_end/lib/src/fragment/factory/declaration.dart
@@ -373,12 +373,14 @@ class FactoryDeclarationImpl
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     _encoding.registerFunctionBody(
       body: body,
       scope: scope,
       asyncMarker: asyncMarker,
       emittedValueType: emittedValueType,
+      thisVariable: thisVariable,
     );
   }
 
@@ -421,6 +423,7 @@ abstract class FactoryFragmentDeclaration {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   });
 
   DartType get returnTypeContext;
diff --git a/pkg/front_end/lib/src/fragment/factory/encoding.dart b/pkg/front_end/lib/src/fragment/factory/encoding.dart
index 9bb605374b8..eae6cfee229 100644
--- a/pkg/front_end/lib/src/fragment/factory/encoding.dart
+++ b/pkg/front_end/lib/src/fragment/factory/encoding.dart
@@ -532,6 +532,7 @@ class FactoryEncoding implements InferredTypeListener {
       scope: null,
       asyncMarker: AsyncMarker.Sync,
       emittedValueType: null,
+      thisVariable: null,
     );
     _procedure.function.redirectingFactoryTarget =
         new RedirectingFactoryTarget.error(message);
@@ -826,6 +827,7 @@ class FactoryEncoding implements InferredTypeListener {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     assert(
       asyncMarker == AsyncMarker.Sync,
@@ -843,6 +845,7 @@ class FactoryEncoding implements InferredTypeListener {
       );
     }
     _procedure.function.scope = scope;
+    _procedure.function.thisVariable = thisVariable;
   }
 
   void becomeNative(SourceLoader loader) {
diff --git a/pkg/front_end/lib/src/fragment/getter/body_builder_context.dart b/pkg/front_end/lib/src/fragment/getter/body_builder_context.dart
index 50850035b87..fbeec4e7308 100644
--- a/pkg/front_end/lib/src/fragment/getter/body_builder_context.dart
+++ b/pkg/front_end/lib/src/fragment/getter/body_builder_context.dart
@@ -74,6 +74,9 @@ class GetterFragmentBodyBuilderContext extends BodyBuilderContext {
           ?.scope,
       asyncMarker: asyncMarker,
       emittedValueType: emittedValueType,
+      thisVariable: scopeProviderInfo
+          // Coverage-ignore(suite): Not run.
+          ?.thisVariable,
     );
   }
 
diff --git a/pkg/front_end/lib/src/fragment/getter/declaration.dart b/pkg/front_end/lib/src/fragment/getter/declaration.dart
index 58970491c8d..2e19e114ee3 100644
--- a/pkg/front_end/lib/src/fragment/getter/declaration.dart
+++ b/pkg/front_end/lib/src/fragment/getter/declaration.dart
@@ -309,6 +309,7 @@ class RegularGetterDeclaration
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     assert(
       asyncMarker == asyncModifier,
@@ -320,6 +321,7 @@ class RegularGetterDeclaration
       scope: scope,
       asyncMarker: asyncMarker,
       emittedValueType: emittedValueType,
+      thisVariable: thisVariable,
     );
   }
 
@@ -367,6 +369,7 @@ abstract class GetterFragmentDeclaration {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   });
 
   DartType get returnTypeContext;
diff --git a/pkg/front_end/lib/src/fragment/getter/encoding.dart b/pkg/front_end/lib/src/fragment/getter/encoding.dart
index 84f0cab29b7..626e4e79b91 100644
--- a/pkg/front_end/lib/src/fragment/getter/encoding.dart
+++ b/pkg/front_end/lib/src/fragment/getter/encoding.dart
@@ -182,6 +182,7 @@ sealed class GetterEncoding implements InferredTypeListener {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   });
 }
 
@@ -466,6 +467,7 @@ mixin _DirectGetterEncodingMixin implements GetterEncoding {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     if (body != null) {
       function.registerFunctionBody(
@@ -475,6 +477,7 @@ mixin _DirectGetterEncodingMixin implements GetterEncoding {
       );
     }
     function.scope = scope;
+    function.thisVariable = thisVariable;
   }
 }
 
@@ -814,6 +817,7 @@ mixin _ExtensionInstanceGetterEncodingMixin implements GetterEncoding {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     if (body != null) {
       function.registerFunctionBody(
@@ -823,5 +827,6 @@ mixin _ExtensionInstanceGetterEncodingMixin implements GetterEncoding {
       );
     }
     function.scope = scope;
+    function.thisVariable = thisVariable;
   }
 }
diff --git a/pkg/front_end/lib/src/fragment/method/body_builder_context.dart b/pkg/front_end/lib/src/fragment/method/body_builder_context.dart
index 87a660c8def..ab812201c5e 100644
--- a/pkg/front_end/lib/src/fragment/method/body_builder_context.dart
+++ b/pkg/front_end/lib/src/fragment/method/body_builder_context.dart
@@ -79,6 +79,7 @@ class MethodFragmentBodyBuilderContext extends BodyBuilderContext {
       scope: scopeProviderInfo?.scope,
       asyncMarker: asyncMarker,
       emittedValueType: emittedValueType,
+      thisVariable: scopeProviderInfo?.thisVariable,
     );
   }
 
diff --git a/pkg/front_end/lib/src/fragment/method/declaration.dart b/pkg/front_end/lib/src/fragment/method/declaration.dart
index e4bd945ef32..a20b996e7ed 100644
--- a/pkg/front_end/lib/src/fragment/method/declaration.dart
+++ b/pkg/front_end/lib/src/fragment/method/declaration.dart
@@ -278,12 +278,14 @@ class MethodDeclarationImpl
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     _encoding.registerFunctionBody(
       body: body,
       scope: scope,
       asyncMarker: asyncMarker,
       emittedValueType: emittedValueType,
+      thisVariable: thisVariable,
     );
   }
 
@@ -307,6 +309,7 @@ abstract class MethodFragmentDeclaration {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   });
 
   DartType get returnTypeContext;
diff --git a/pkg/front_end/lib/src/fragment/method/encoding.dart b/pkg/front_end/lib/src/fragment/method/encoding.dart
index 6cb98725a52..b5e0dd59d75 100644
--- a/pkg/front_end/lib/src/fragment/method/encoding.dart
+++ b/pkg/front_end/lib/src/fragment/method/encoding.dart
@@ -98,6 +98,7 @@ sealed class MethodEncoding implements InferredTypeListener {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   });
 }
 
@@ -393,6 +394,7 @@ mixin _DirectMethodEncodingMixin implements MethodEncoding {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     if (body != null) {
       function.registerFunctionBody(
@@ -402,6 +404,7 @@ mixin _DirectMethodEncodingMixin implements MethodEncoding {
       );
     }
     function.scope = scope;
+    function.thisVariable = thisVariable;
   }
 }
 
@@ -796,6 +799,7 @@ mixin _ExtensionInstanceMethodEncodingMixin implements MethodEncoding {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     if (body != null) {
       function.registerFunctionBody(
@@ -805,6 +809,7 @@ mixin _ExtensionInstanceMethodEncodingMixin implements MethodEncoding {
       );
     }
     function.scope = scope;
+    function.thisVariable = thisVariable;
   }
 
   /// Creates a top level function that creates a tear off of an extension
diff --git a/pkg/front_end/lib/src/fragment/setter/body_builder_context.dart b/pkg/front_end/lib/src/fragment/setter/body_builder_context.dart
index 8e236509a08..cb1ed9444fa 100644
--- a/pkg/front_end/lib/src/fragment/setter/body_builder_context.dart
+++ b/pkg/front_end/lib/src/fragment/setter/body_builder_context.dart
@@ -76,6 +76,9 @@ class SetterBodyBuilderContext extends BodyBuilderContext {
           ?.scope,
       asyncMarker: asyncMarker,
       emittedValueType: emittedValueType,
+      thisVariable: scopeProviderInfo
+          // Coverage-ignore(suite): Not run.
+          ?.thisVariable,
     );
   }
 
diff --git a/pkg/front_end/lib/src/fragment/setter/declaration.dart b/pkg/front_end/lib/src/fragment/setter/declaration.dart
index 8c6defcec06..e0566e2bfb7 100644
--- a/pkg/front_end/lib/src/fragment/setter/declaration.dart
+++ b/pkg/front_end/lib/src/fragment/setter/declaration.dart
@@ -310,6 +310,7 @@ class RegularSetterDeclaration
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     List<FormalParameterBuilder>? declaredFormals = _fragment.declaredFormals;
     if (declaredFormals == null ||
@@ -354,6 +355,7 @@ class RegularSetterDeclaration
       scope: scope,
       asyncMarker: asyncMarker,
       emittedValueType: emittedValueType,
+      thisVariable: thisVariable,
     );
   }
 
@@ -404,6 +406,7 @@ abstract class SetterFragmentDeclaration {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   });
 
   DartType get returnTypeContext;
diff --git a/pkg/front_end/lib/src/fragment/setter/encoding.dart b/pkg/front_end/lib/src/fragment/setter/encoding.dart
index 8fc33ba5112..746cb38b206 100644
--- a/pkg/front_end/lib/src/fragment/setter/encoding.dart
+++ b/pkg/front_end/lib/src/fragment/setter/encoding.dart
@@ -198,6 +198,7 @@ sealed class SetterEncoding {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   });
 }
 
@@ -480,6 +481,7 @@ mixin _DirectSetterEncodingMixin implements SetterEncoding {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     if (body != null) {
       function.registerFunctionBody(
@@ -489,6 +491,7 @@ mixin _DirectSetterEncodingMixin implements SetterEncoding {
       );
     }
     function.scope = scope;
+    function.thisVariable = thisVariable;
   }
 }
 
@@ -849,6 +852,7 @@ mixin _ExtensionInstanceSetterEncodingMixin implements SetterEncoding {
     required Scope? scope,
     required AsyncMarker asyncMarker,
     required DartType? emittedValueType,
+    required VariableDeclaration? thisVariable,
   }) {
     if (body != null) {
       function.registerFunctionBody(
@@ -858,5 +862,6 @@ mixin _ExtensionInstanceSetterEncodingMixin implements SetterEncoding {
       );
     }
     function.scope = scope;
+    function.thisVariable = thisVariable;
   }
 }
diff --git a/pkg/front_end/lib/src/type_inference/context_allocation_strategy.dart b/pkg/front_end/lib/src/type_inference/context_allocation_strategy.dart
index f86efb64b02..dc80048e7f8 100644
--- a/pkg/front_end/lib/src/type_inference/context_allocation_strategy.dart
+++ b/pkg/front_end/lib/src/type_inference/context_allocation_strategy.dart
@@ -35,6 +35,7 @@ class ScopeProviderInfo {
   final ScopeProviderInfoKind kind;
 
   Scope? scope;
+  VariableDeclaration? thisVariable;
 
   ScopeProviderInfo({required this.kind});
 }
@@ -260,6 +261,9 @@ class LoopDepthAllocationStrategy
     required CaptureKind captureKind,
   }) {
     CollectorScopeProviderInfo currentScope = _currentScopeProviderInfo!;
+    if (variable is ThisVariable) {
+      currentScope.thisVariable = variable;
+    }
 
     // Delegation happens when the current variable is not uncaptured (that is,
     // it's either captured or assert-captured), and there's a collector to
diff --git a/pkg/kernel/lib/clone.dart b/pkg/kernel/lib/clone.dart
index 327ec92ead5..3e5ea9af643 100644
--- a/pkg/kernel/lib/clone.dart
+++ b/pkg/kernel/lib/clone.dart
@@ -886,6 +886,7 @@ class CloneVisitorNotMembers
         .map(clone)
         .toList();
     List<VariableDeclaration> named = node.namedParameters.map(clone).toList();
+    VariableDeclaration? thisVariable = cloneOptional(node.thisVariable);
     final DartType? futureValueType = node.emittedValueType != null
         ? visitType(node.emittedValueType!)
         : null;
@@ -894,6 +895,7 @@ class CloneVisitorNotMembers
       typeParameters: typeParameters,
       positionalParameters: positional,
       namedParameters: named,
+      thisVariable: thisVariable,
       requiredParameterCount: node.requiredParameterCount,
       returnType: visitType(node.returnType),
       asyncMarker: node.asyncMarker,
diff --git a/pkg/kernel/lib/src/ast/functions.dart b/pkg/kernel/lib/src/ast/functions.dart
index 2d9c5afc1ba..44181fbdd77 100644
--- a/pkg/kernel/lib/src/ast/functions.dart
+++ b/pkg/kernel/lib/src/ast/functions.dart
@@ -41,6 +41,7 @@ class FunctionNode extends TreeNode implements ScopeProvider, ContextConsumer {
   int requiredParameterCount;
   List<VariableDeclaration> positionalParameters;
   List<VariableDeclaration> namedParameters;
+  VariableDeclaration? thisVariable;
   DartType returnType; // Not null.
   Statement? _body;
 
@@ -110,6 +111,7 @@ class FunctionNode extends TreeNode implements ScopeProvider, ContextConsumer {
     this.asyncMarker = AsyncMarker.Sync,
     AsyncMarker? dartAsyncMarker,
     this.emittedValueType,
+    this.thisVariable,
   }) : this.positionalParameters =
            positionalParameters ?? <VariableDeclaration>[],
        this.requiredParameterCount =
diff --git a/pkg/kernel/lib/src/equivalence.dart b/pkg/kernel/lib/src/equivalence.dart
index ef7e09715d0..55c79d1aeef 100644
--- a/pkg/kernel/lib/src/equivalence.dart
+++ b/pkg/kernel/lib/src/equivalence.dart
@@ -4367,6 +4367,9 @@ class EquivalenceStrategy {
     if (!checkFunctionNode_namedParameters(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
+    if (!checkFunctionNode_thisVariable(visitor, node, other)) {
+      result = visitor.resultOnInequivalence;
+    }
     if (!checkFunctionNode_returnType(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
@@ -10832,6 +10835,18 @@ class EquivalenceStrategy {
     );
   }
 
+  bool checkFunctionNode_thisVariable(
+    EquivalenceVisitor visitor,
+    FunctionNode node,
+    FunctionNode other,
+  ) {
+    return visitor.checkNodes(
+      node.thisVariable,
+      other.thisVariable,
+      'thisVariable',
+    );
+  }
+
   bool checkFunctionNode_returnType(
     EquivalenceVisitor visitor,
     FunctionNode node,