[cfe][PrimaryConstructors] Use MemberLookupResult for redirecting initializers

This uses MemberLookupResult instead of Builder as the result for BodyBuilderContext.lookupConstructor. This allows for a more precise handling of error cases and avoids reporting cascading error in case of duplicate constructors.

Change-Id: I465747883af594870cb0663e80a188e6dd1b552b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/486202
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Erik Ernst <eernst@google.com>

pkg/_fe_analyzer_shared/lib/src/messages/diagnostic.g.dart

@@ -2566,6 +2566,16 @@ const MessageCode recordTypeZeroFieldsButTrailingComma = const MessageCode(
   correctionMessage: """Try removing the trailing comma.""",
 );
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const MessageCode
+redirectGenerativeToNonGenerativeConstructor = const MessageCode(
+  "RedirectGenerativeToNonGenerativeConstructor",
+  sharedCode: SharedCode.redirectGenerativeToNonGenerativeConstructor,
+  problemMessage:
+      """Generative constructors can't redirect to a factory constructor.""",
+  correctionMessage: """Try redirecting to a different constructor.""",
+);
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const MessageCode redirectingConstructorWithBody = const MessageCode(
   "RedirectingConstructorWithBody",
@@ -3187,6 +3197,7 @@ enum SharedCode {
   primaryConstructorBodyWithoutDeclaration,
   recordLiteralOnePositionalNoTrailingComma,
   recordTypeOnePositionalNoTrailingComma,
+  redirectGenerativeToNonGenerativeConstructor,
   redirectingConstructorWithBody,
   redirectionInNonFactoryConstructor,
   sealedEnum,

pkg/_fe_analyzer_shared/messages.yaml

@@ -2706,3 +2706,55 @@ fieldInitializedInDeclarationAndParameterOfPrimaryConstructor:
     class C(this.x) {
       int x = 0;
     }
+
+redirectGenerativeToNonGenerativeConstructor:
+  type: compileTimeError
+  parameters: none
+  problemMessage: "Generative constructors can't redirect to a factory constructor."
+  correctionMessage: Try redirecting to a different constructor.
+  hasPublishedDocs: true
+  analyzerCode: redirectGenerativeToNonGenerativeConstructor
+  documentation: |-
+    #### Description
+
+    The analyzer produces this diagnostic when a generative constructor
+    redirects to a factory constructor.
+
+    #### Example
+
+    The following code produces this diagnostic because the generative
+    constructor `C.a` redirects to the factory constructor `C.b`:
+
+    ```dart
+    class C {
+      C.a() : [!this.b()!];
+      factory C.b() => C.a();
+    }
+    ```
+
+    #### Common fixes
+
+    If the generative constructor doesn't need to redirect to another
+    constructor, then remove the redirect.
+
+    ```dart
+    class C {
+      C.a();
+      factory C.b() => C.a();
+    }
+    ```
+
+    If the generative constructor must redirect to another constructor, then
+    make the other constructor be a generative (non-factory) constructor:
+
+    ```dart
+    class C {
+      C.a() : this.b();
+      C.b();
+    }
+    ```
+  script: |
+    class C {
+      factory C() => throw '';
+      C.named() : this();
+    }

pkg/analyzer/lib/src/diagnostic/diagnostic_code_values.g.dart

@@ -1287,6 +1287,7 @@ final sharedAnalyzerCodes = <DiagnosticCode>[
   diag.primaryConstructorBodyWithoutDeclaration,
   diag.recordLiteralOnePositionalNoTrailingComma,
   diag.recordTypeOnePositionalNoTrailingComma,
+  diag.redirectGenerativeToNonGenerativeConstructor,
   diag.redirectingConstructorWithBody,
   diag.redirectionInNonFactoryConstructor,
   diag.sealedEnum,

pkg/analyzer/messages.yaml

@@ -15418,51 +15418,6 @@ CompileTimeErrorCode:
         C.a();
       }
       ```
-  redirectGenerativeToNonGenerativeConstructor:
-    type: compileTimeError
-    parameters: none
-    problemMessage: "Generative constructors can't redirect to a factory constructor."
-    correctionMessage: Try redirecting to a different constructor.
-    hasPublishedDocs: true
-    documentation: |-
-      #### Description
-
-      The analyzer produces this diagnostic when a generative constructor
-      redirects to a factory constructor.
-
-      #### Example
-
-      The following code produces this diagnostic because the generative
-      constructor `C.a` redirects to the factory constructor `C.b`:
-
-      ```dart
-      class C {
-        C.a() : [!this.b()!];
-        factory C.b() => C.a();
-      }
-      ```
-
-      #### Common fixes
-
-      If the generative constructor doesn't need to redirect to another
-      constructor, then remove the redirect.
-
-      ```dart
-      class C {
-        C.a();
-        factory C.b() => C.a();
-      }
-      ```
-
-      If the generative constructor must redirect to another constructor, then
-      make the other constructor be a generative (non-factory) constructor:
-
-      ```dart
-      class C {
-        C.a() : this.b();
-        C.b();
-      }
-      ```
   redirectToAbstractClassConstructor:
     type: compileTimeError
     parameters:

pkg/front_end/lib/src/kernel/body_builder.dart

@@ -35,7 +35,6 @@ import 'package:_fe_analyzer_shared/src/scanner/token_impl.dart'
 import 'package:_fe_analyzer_shared/src/type_inference/assigned_variables.dart';
 import 'package:_fe_analyzer_shared/src/util/link.dart';
 import 'package:_fe_analyzer_shared/src/util/value_kind.dart';
-import 'package:front_end/src/codes/diagnostic.dart' as diag;
 import 'package:kernel/ast.dart';
 import 'package:kernel/class_hierarchy.dart';
 import 'package:kernel/core_types.dart';
@@ -86,8 +85,11 @@ import '../builder/type_builder.dart';
 import '../builder/variable_builder.dart';
 import '../builder/void_type_builder.dart';
 import '../codes/cfe_codes.dart' as cfe;
+import '../codes/diagnostic.dart' as diag;
 import '../source/check_helper.dart';
 import '../source/diet_parser.dart';
+import '../source/source_constructor_builder.dart';
+import '../source/source_factory_builder.dart';
 import '../source/source_library_builder.dart';
 import '../source/source_member_builder.dart';
 import '../source/source_property_builder.dart';
@@ -10088,8 +10090,8 @@ class BodyBuilderImpl extends StackListenerImpl
     ActualArguments arguments, {
     required int fileOffset,
   }) {
-    Builder? constructorBuilder = _context.lookupConstructor(name);
-    if (constructorBuilder == null) {
+    MemberLookupResult? result = _context.lookupConstructor(name);
+    if (result == null) {
       int length = name.text.length;
       if (length == 0) {
         // The constructor is unnamed so the offset points to 'this'.
@@ -10105,30 +10107,66 @@ class BodyBuilderImpl extends StackListenerImpl
         ),
         isRedirectingInitializer: true,
       );
+    } else if (result.isInvalidLookup) {
+      return createInvalidInitializer(
+        LookupResult.createDuplicateExpression(
+          result,
+          context: compilerContext,
+          name: name.text,
+          fileUri: uri,
+          fileOffset: fileOffset,
+          length: noLength,
+        ),
+        isRedirectingInitializer: true,
+      );
     } else {
-      if (_context.isConstructorCyclic(name.text)) {
-        int length = name.text.length;
-        if (length == 0) length = "this".length;
-        addProblem(diag.constructorCyclic, fileOffset, length);
-        // TODO(askesc): Produce invalid initializer.
-      }
-      if (_context.formals != null) {
-        for (FormalParameterBuilder formal in _context.formals!) {
-          if (formal.isSuperInitializingFormal) {
-            addProblem(
-              diag.unexpectedSuperParametersInGenerativeConstructors,
-              formal.fileOffset,
-              noLength,
-            );
-            _context.markAsErroneous();
+      MemberBuilder builder = result.getable!;
+      if (builder is SourceFactoryBuilder) {
+        return createInvalidInitializer(
+          buildProblem(
+            message: diag.redirectGenerativeToNonGenerativeConstructor,
+            fileUri: uri,
+            fileOffset: fileOffset,
+            length: noLength,
+          ),
+          isRedirectingInitializer: true,
+        );
+      } else {
+        assert(
+          builder is SourceConstructorBuilder,
+          "Unexpected constructor builder $builder.",
+        );
+        if (_context.isConstructorCyclic(name.text)) {
+          int length = name.text.length;
+          if (length == 0) length = "this".length;
+          return createInvalidInitializer(
+            buildProblem(
+              message: diag.constructorCyclic,
+              fileUri: uri,
+              fileOffset: fileOffset,
+              length: length,
+            ),
+            isRedirectingInitializer: true,
+          );
+        }
+        if (_context.formals != null) {
+          for (FormalParameterBuilder formal in _context.formals!) {
+            if (formal.isSuperInitializingFormal) {
+              addProblem(
+                diag.unexpectedSuperParametersInGenerativeConstructors,
+                formal.fileOffset,
+                noLength,
+              );
+              _context.markAsErroneous();
+            }
           }
         }
+        return _context.buildRedirectingInitializer(
+          builder,
+          arguments,
+          fileOffset: fileOffset,
+        );
       }
-      return _context.buildRedirectingInitializer(
-        constructorBuilder,
-        arguments,
-        fileOffset: fileOffset,
-      );
     }
   }
 

pkg/front_end/lib/src/kernel/body_builder_context.dart

@@ -10,15 +10,14 @@ import 'package:kernel/transformations/flags.dart';
 import '../base/constant_context.dart' show ConstantContext;
 import '../base/local_scope.dart';
 import '../base/lookup_result.dart';
-import '../builder/builder.dart';
 import '../builder/declaration_builders.dart';
 import '../builder/formal_parameter_builder.dart';
 import '../builder/library_builder.dart';
+import '../builder/member_builder.dart';
 import '../builder/named_type_builder.dart';
 import '../builder/type_builder.dart';
 import '../dill/dill_class_builder.dart';
 import '../source/source_class_builder.dart';
-import '../source/source_constructor_builder.dart';
 import '../source/source_enum_builder.dart';
 import '../source/source_extension_builder.dart';
 import '../source/source_extension_type_declaration_builder.dart';
@@ -94,7 +93,7 @@ abstract class BodyBuilderContext {
   }
 
   /// Looks up the constructor by the given [name] in the enclosing declaration.
-  Builder? lookupConstructor(Name name) {
+  MemberLookupResult? lookupConstructor(Name name) {
     return declarationContext.lookupConstructor(name);
   }
 
@@ -102,7 +101,7 @@ abstract class BodyBuilderContext {
   /// [constructorBuilder] with the given [arguments] from within a constructor
   /// in the same class.
   Initializer buildRedirectingInitializer(
-    Builder constructorBuilder,
+    MemberBuilder constructorBuilder,
     ActualArguments arguments, {
     required int fileOffset,
   }) {
@@ -459,12 +458,12 @@ abstract class BodyBuilderDeclarationContext {
     throw new UnsupportedError('${runtimeType}.lookupSuperMember');
   }
 
-  Builder? lookupConstructor(Name name) {
+  MemberLookupResult? lookupConstructor(Name name) {
     throw new UnsupportedError('${runtimeType}.lookupConstructor');
   }
 
   Initializer buildRedirectingInitializer(
-    Builder constructorBuilder,
+    MemberBuilder constructorBuilder,
     ActualArguments arguments, {
     required int fileOffset,
   }) {
@@ -568,13 +567,13 @@ class _SourceClassBodyBuilderDeclarationContext
   }
 
   @override
-  SourceConstructorBuilder? lookupConstructor(Name name) {
+  MemberLookupResult? lookupConstructor(Name name) {
     return _sourceClassBuilder.lookupConstructor(name);
   }
 
   @override
   Initializer buildRedirectingInitializer(
-    covariant SourceConstructorBuilder constructorBuilder,
+    MemberBuilder constructorBuilder,
     ActualArguments arguments, {
     required int fileOffset,
   }) {
@@ -667,7 +666,7 @@ class _SourceExtensionTypeDeclarationBodyBuilderDeclarationContext
       _sourceExtensionTypeDeclarationBuilder;
 
   @override
-  SourceConstructorBuilder? lookupConstructor(Name name) {
+  MemberLookupResult? lookupConstructor(Name name) {
     return _sourceExtensionTypeDeclarationBuilder.lookupConstructor(name);
   }
 
@@ -679,7 +678,7 @@ class _SourceExtensionTypeDeclarationBodyBuilderDeclarationContext
 
   @override
   Initializer buildRedirectingInitializer(
-    covariant SourceConstructorBuilder constructorBuilder,
+    MemberBuilder constructorBuilder,
     ActualArguments arguments, {
     required int fileOffset,
   }) {

pkg/front_end/lib/src/kernel/expression_generator.dart

@@ -6664,7 +6664,7 @@ class ThisAccessGenerator extends Generator {
           return createInvalidInitializer(
             LookupResult.createDuplicateExpression(
               result,
-              context: _helper.libraryBuilder.loader.target.context,
+              context: _helper.compilerContext,
               name: name.text,
               fileUri: _helper.uri,
               fileOffset: offset,

pkg/front_end/lib/src/source/source_class_builder.dart

@@ -642,16 +642,12 @@ class SourceClassBuilder extends ClassBuilderImpl
 
   /// Looks up the constructor by [name] on the class built by this class
   /// builder.
-  SourceConstructorBuilder? lookupConstructor(Name name) {
+  MemberLookupResult? lookupConstructor(Name name) {
     if (name.text == "new") {
       name = new Name("", name.library);
     }
 
-    Builder? builder = nameSpace.lookupConstructor(name.text)?.getable;
-    if (builder is SourceConstructorBuilder) {
-      return builder;
-    }
-    return null;
+    return nameSpace.lookupConstructor(name.text);
   }
 
   /// Looks up the super constructor by [name] on the superclass of the class

pkg/front_end/lib/src/source/source_extension_type_declaration_builder.dart

@@ -10,13 +10,13 @@ import 'package:kernel/reference_from_index.dart';
 import 'package:kernel/type_algebra.dart';
 import 'package:kernel/type_environment.dart';
 
+import '../base/lookup_result.dart';
 import '../base/messages.dart';
 import '../base/modifiers.dart';
 import '../base/name_space.dart';
 import '../base/problems.dart';
 import '../base/scope.dart';
 import '../builder/augmentation_iterator.dart';
-import '../builder/builder.dart';
 import '../builder/constructor_reference_builder.dart';
 import '../builder/declaration_builders.dart';
 import '../builder/formal_parameter_builder.dart';
@@ -34,7 +34,6 @@ import '../type_inference/type_inference_engine.dart';
 import 'name_scheme.dart';
 import 'name_space_builder.dart';
 import 'source_builder_mixins.dart';
-import 'source_constructor_builder.dart';
 import 'source_factory_builder.dart';
 import 'source_library_builder.dart';
 import 'source_member_builder.dart';
@@ -1016,17 +1015,13 @@ class SourceExtensionTypeDeclarationBuilder
 
   /// Looks up the constructor by [name] on the class built by this class
   /// builder.
-  SourceConstructorBuilder? lookupConstructor(Name name) {
+  MemberLookupResult? lookupConstructor(Name name) {
     if (name.text == "new") {
       // Coverage-ignore-block(suite): Not run.
       name = new Name("", name.library);
     }
 
-    Builder? builder = nameSpace.lookupConstructor(name.text)?.getable;
-    if (builder is SourceConstructorBuilder) {
-      return builder;
-    }
-    return null;
+    return nameSpace.lookupConstructor(name.text);
   }
 
   DartType get _declaredRepresentationType =>

pkg/front_end/testcases/general/constructor_cycle.dart.strong.expect

@@ -20,13 +20,19 @@ class A extends core::Object {
     : this self::A::bar()
     ;
   constructor bar() → self::A
-    : this self::A::foo()
+    : invalid-initializer "pkg/front_end/testcases/general/constructor_cycle.dart:7:18: Error: Redirecting constructors can't be cyclic.
+Try to have all constructors eventually redirect to a non-redirecting constructor.
+  A.bar() : this.foo();
+                 ^^^"
     ;
   constructor baz() → self::A
     : this self::A::foo()
     ;
   constructor •() → self::A
-    : this self::A::•()
+    : invalid-initializer "pkg/front_end/testcases/general/constructor_cycle.dart:9:9: Error: Redirecting constructors can't be cyclic.
+Try to have all constructors eventually redirect to a non-redirecting constructor.
+  A() : this();
+        ^^^^"
     ;
 }
 static method main() → dynamic {}

pkg/front_end/testcases/general/constructor_cycle.dart.strong.modular.expect

@@ -20,13 +20,19 @@ class A extends core::Object {
     : this self::A::bar()
     ;
   constructor bar() → self::A
-    : this self::A::foo()
+    : invalid-initializer "pkg/front_end/testcases/general/constructor_cycle.dart:7:18: Error: Redirecting constructors can't be cyclic.
+Try to have all constructors eventually redirect to a non-redirecting constructor.
+  A.bar() : this.foo();
+                 ^^^"
     ;
   constructor baz() → self::A
     : this self::A::foo()
     ;
   constructor •() → self::A
-    : this self::A::•()
+    : invalid-initializer "pkg/front_end/testcases/general/constructor_cycle.dart:9:9: Error: Redirecting constructors can't be cyclic.
+Try to have all constructors eventually redirect to a non-redirecting constructor.
+  A() : this();
+        ^^^^"
     ;
 }
 static method main() → dynamic {}

pkg/front_end/testcases/general/constructor_cycle.dart.strong.transformed.expect

@@ -20,13 +20,19 @@ class A extends core::Object {
     : this self::A::bar()
     ;
   constructor bar() → self::A
-    : this self::A::foo()
+    : invalid-initializer "pkg/front_end/testcases/general/constructor_cycle.dart:7:18: Error: Redirecting constructors can't be cyclic.
+Try to have all constructors eventually redirect to a non-redirecting constructor.
+  A.bar() : this.foo();
+                 ^^^"
     ;
   constructor baz() → self::A
     : this self::A::foo()
     ;
   constructor •() → self::A
-    : this self::A::•()
+    : invalid-initializer "pkg/front_end/testcases/general/constructor_cycle.dart:9:9: Error: Redirecting constructors can't be cyclic.
+Try to have all constructors eventually redirect to a non-redirecting constructor.
+  A() : this();
+        ^^^^"
     ;
 }
 static method main() → dynamic {}

pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart.strong.expect

@@ -76,35 +76,19 @@ library;
 //   C<T>() : this();
 //   ^
 //
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Couldn't find constructor 'C'.
-//   C<T>() : this();
-//            ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Couldn't find constructor 'C'.
-//   C!<T>() : this();
-//             ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:4:11: Error: Couldn't find constructor 'C'.
-//   C<T() : this();
-//           ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:5:13: Error: Couldn't find constructor 'C'.
-//   C<T>=() : this();
-//             ^^^^
-//
 import self as self;
 import "dart:core" as core;
 
 class C extends core::Object {
   field dynamic C = null;
   constructor •() → self::C
-    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Couldn't find constructor 'C'.
+    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Can't use 'new' because it is declared more than once.
   C<T>() : this();
-           ^^^^"
+           ^"
     ;
   constructor !() → self::C
-    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Couldn't find constructor 'C'.
+    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Can't use 'new' because it is declared more than once.
   C!<T>() : this();
-            ^^^^"
+            ^"
     ;
 }

pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart.strong.modular.expect

@@ -76,35 +76,19 @@ library;
 //   C<T>() : this();
 //   ^
 //
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Couldn't find constructor 'C'.
-//   C<T>() : this();
-//            ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Couldn't find constructor 'C'.
-//   C!<T>() : this();
-//             ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:4:11: Error: Couldn't find constructor 'C'.
-//   C<T() : this();
-//           ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:5:13: Error: Couldn't find constructor 'C'.
-//   C<T>=() : this();
-//             ^^^^
-//
 import self as self;
 import "dart:core" as core;
 
 class C extends core::Object {
   field dynamic C = null;
   constructor •() → self::C
-    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Couldn't find constructor 'C'.
+    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Can't use 'new' because it is declared more than once.
   C<T>() : this();
-           ^^^^"
+           ^"
     ;
   constructor !() → self::C
-    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Couldn't find constructor 'C'.
+    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Can't use 'new' because it is declared more than once.
   C!<T>() : this();
-            ^^^^"
+            ^"
     ;
 }

pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart.strong.transformed.expect

@@ -76,35 +76,19 @@ library;
 //   C<T>() : this();
 //   ^
 //
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Couldn't find constructor 'C'.
-//   C<T>() : this();
-//            ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Couldn't find constructor 'C'.
-//   C!<T>() : this();
-//             ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:4:11: Error: Couldn't find constructor 'C'.
-//   C<T() : this();
-//           ^^^^
-//
-// pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:5:13: Error: Couldn't find constructor 'C'.
-//   C<T>=() : this();
-//             ^^^^
-//
 import self as self;
 import "dart:core" as core;
 
 class C extends core::Object {
   field dynamic C = null;
   constructor •() → self::C
-    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Couldn't find constructor 'C'.
+    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:2:12: Error: Can't use 'new' because it is declared more than once.
   C<T>() : this();
-           ^^^^"
+           ^"
     ;
   constructor !() → self::C
-    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Couldn't find constructor 'C'.
+    : invalid-initializer "pkg/front_end/testcases/general/error_recovery/constructor_recovery_type_parameters.dart:3:13: Error: Can't use 'new' because it is declared more than once.
   C!<T>() : this();
-            ^^^^"
+            ^"
     ;
 }

pkg/front_end/testcases/general/redirect_to_duplicate.dart

@@ -0,0 +1,25 @@
+// Copyright (c) 2026, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class C1 {
+  C1();
+  C1();
+  C1.named() : this();
+}
+
+class C2 {
+  C2.named();
+  C2.named();
+  C2() : this.named();
+}
+
+extension type ET1(int i) {
+  ET1(this.i);
+  ET1.named(int i) : this(i);
+}
+
+extension type ET2.named(int i) {
+  ET2.named(this.i);
+  ET2(int i) : this.named(i);
+}

pkg/front_end/testcases/general/redirect_to_duplicate.dart.strong.expect

@@ -0,0 +1,99 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:7:3: Error: 'C1' is already declared in this scope.
+//   C1();
+//   ^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:6:3: Context: Previous declaration of 'C1'.
+//   C1();
+//   ^^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:13:3: Error: 'C2.named' is already declared in this scope.
+//   C2.named();
+//   ^^^^^^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:12:3: Context: Previous declaration of 'C2.named'.
+//   C2.named();
+//   ^^^^^^^^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:18:3: Error: 'ET1' is already declared in this scope.
+//   ET1(this.i);
+//   ^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:17:19: Context: Previous declaration of 'ET1'.
+// extension type ET1(int i) {
+//                   ^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:23:3: Error: 'ET2.named' is already declared in this scope.
+//   ET2.named(this.i);
+//   ^^^^^^^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:22:20: Context: Previous declaration of 'ET2.named'.
+// extension type ET2.named(int i) {
+//                    ^
+//
+import self as self;
+import "dart:core" as core;
+
+class C1 extends core::Object {
+  constructor •() → self::C1
+    : super core::Object::•()
+    ;
+  constructor named() → self::C1
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_duplicate.dart:8:16: Error: Can't use 'new' because it is declared more than once.
+  C1.named() : this();
+               ^"
+    ;
+}
+class C2 extends core::Object {
+  constructor named() → self::C2
+    : super core::Object::•()
+    ;
+  constructor •() → self::C2
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_duplicate.dart:14:15: Error: Can't use 'named' because it is declared more than once.
+  C2() : this.named();
+              ^"
+    ;
+}
+extension type ET1(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+  constructor named = self::ET1|constructor#named;
+  constructor tearoff named = self::ET1|constructor#_#named#tearOff;
+}
+extension type ET2(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor named = self::ET2|constructor#named;
+  constructor tearoff named = self::ET2|constructor#_#named#tearOff;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static extension-type-member method ET1|constructor#(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#new#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#(i);
+static extension-type-member method ET1|constructor#named(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_duplicate.dart:19:22: Error: Can't use 'new' because it is declared more than once.
+  ET1.named(int i) : this(i);
+                     ^";
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#named#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#named(i);
+static extension-type-member method ET2|constructor#named(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#named#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#named(i);
+static extension-type-member method ET2|constructor#(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_duplicate.dart:24:21: Error: Can't use 'named' because it is declared more than once.
+  ET2(int i) : this.named(i);
+                    ^";
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#new#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#(i);

pkg/front_end/testcases/general/redirect_to_duplicate.dart.strong.modular.expect

@@ -0,0 +1,99 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:7:3: Error: 'C1' is already declared in this scope.
+//   C1();
+//   ^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:6:3: Context: Previous declaration of 'C1'.
+//   C1();
+//   ^^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:13:3: Error: 'C2.named' is already declared in this scope.
+//   C2.named();
+//   ^^^^^^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:12:3: Context: Previous declaration of 'C2.named'.
+//   C2.named();
+//   ^^^^^^^^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:18:3: Error: 'ET1' is already declared in this scope.
+//   ET1(this.i);
+//   ^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:17:19: Context: Previous declaration of 'ET1'.
+// extension type ET1(int i) {
+//                   ^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:23:3: Error: 'ET2.named' is already declared in this scope.
+//   ET2.named(this.i);
+//   ^^^^^^^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:22:20: Context: Previous declaration of 'ET2.named'.
+// extension type ET2.named(int i) {
+//                    ^
+//
+import self as self;
+import "dart:core" as core;
+
+class C1 extends core::Object {
+  constructor •() → self::C1
+    : super core::Object::•()
+    ;
+  constructor named() → self::C1
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_duplicate.dart:8:16: Error: Can't use 'new' because it is declared more than once.
+  C1.named() : this();
+               ^"
+    ;
+}
+class C2 extends core::Object {
+  constructor named() → self::C2
+    : super core::Object::•()
+    ;
+  constructor •() → self::C2
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_duplicate.dart:14:15: Error: Can't use 'named' because it is declared more than once.
+  C2() : this.named();
+              ^"
+    ;
+}
+extension type ET1(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+  constructor named = self::ET1|constructor#named;
+  constructor tearoff named = self::ET1|constructor#_#named#tearOff;
+}
+extension type ET2(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor named = self::ET2|constructor#named;
+  constructor tearoff named = self::ET2|constructor#_#named#tearOff;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static extension-type-member method ET1|constructor#(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#new#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#(i);
+static extension-type-member method ET1|constructor#named(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_duplicate.dart:19:22: Error: Can't use 'new' because it is declared more than once.
+  ET1.named(int i) : this(i);
+                     ^";
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#named#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#named(i);
+static extension-type-member method ET2|constructor#named(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#named#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#named(i);
+static extension-type-member method ET2|constructor#(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_duplicate.dart:24:21: Error: Can't use 'named' because it is declared more than once.
+  ET2(int i) : this.named(i);
+                    ^";
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#new#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#(i);

pkg/front_end/testcases/general/redirect_to_duplicate.dart.strong.outline.expect

@@ -0,0 +1,77 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:7:3: Error: 'C1' is already declared in this scope.
+//   C1();
+//   ^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:6:3: Context: Previous declaration of 'C1'.
+//   C1();
+//   ^^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:13:3: Error: 'C2.named' is already declared in this scope.
+//   C2.named();
+//   ^^^^^^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:12:3: Context: Previous declaration of 'C2.named'.
+//   C2.named();
+//   ^^^^^^^^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:18:3: Error: 'ET1' is already declared in this scope.
+//   ET1(this.i);
+//   ^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:17:19: Context: Previous declaration of 'ET1'.
+// extension type ET1(int i) {
+//                   ^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:23:3: Error: 'ET2.named' is already declared in this scope.
+//   ET2.named(this.i);
+//   ^^^^^^^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:22:20: Context: Previous declaration of 'ET2.named'.
+// extension type ET2.named(int i) {
+//                    ^
+//
+import self as self;
+import "dart:core" as core;
+
+class C1 extends core::Object {
+  constructor •() → self::C1
+    ;
+  constructor named() → self::C1
+    ;
+}
+class C2 extends core::Object {
+  constructor named() → self::C2
+    ;
+  constructor •() → self::C2
+    ;
+}
+extension type ET1(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+  constructor named = self::ET1|constructor#named;
+  constructor tearoff named = self::ET1|constructor#_#named#tearOff;
+}
+extension type ET2(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor named = self::ET2|constructor#named;
+  constructor tearoff named = self::ET2|constructor#_#named#tearOff;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static extension-type-member method ET1|constructor#(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET1|constructor#_#new#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#(i);
+static extension-type-member method ET1|constructor#named(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET1|constructor#_#named#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#named(i);
+static extension-type-member method ET2|constructor#named(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET2|constructor#_#named#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#named(i);
+static extension-type-member method ET2|constructor#(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET2|constructor#_#new#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#(i);

pkg/front_end/testcases/general/redirect_to_duplicate.dart.strong.transformed.expect

@@ -0,0 +1,99 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:7:3: Error: 'C1' is already declared in this scope.
+//   C1();
+//   ^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:6:3: Context: Previous declaration of 'C1'.
+//   C1();
+//   ^^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:13:3: Error: 'C2.named' is already declared in this scope.
+//   C2.named();
+//   ^^^^^^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:12:3: Context: Previous declaration of 'C2.named'.
+//   C2.named();
+//   ^^^^^^^^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:18:3: Error: 'ET1' is already declared in this scope.
+//   ET1(this.i);
+//   ^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:17:19: Context: Previous declaration of 'ET1'.
+// extension type ET1(int i) {
+//                   ^
+//
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:23:3: Error: 'ET2.named' is already declared in this scope.
+//   ET2.named(this.i);
+//   ^^^^^^^^^
+// pkg/front_end/testcases/general/redirect_to_duplicate.dart:22:20: Context: Previous declaration of 'ET2.named'.
+// extension type ET2.named(int i) {
+//                    ^
+//
+import self as self;
+import "dart:core" as core;
+
+class C1 extends core::Object {
+  constructor •() → self::C1
+    : super core::Object::•()
+    ;
+  constructor named() → self::C1
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_duplicate.dart:8:16: Error: Can't use 'new' because it is declared more than once.
+  C1.named() : this();
+               ^"
+    ;
+}
+class C2 extends core::Object {
+  constructor named() → self::C2
+    : super core::Object::•()
+    ;
+  constructor •() → self::C2
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_duplicate.dart:14:15: Error: Can't use 'named' because it is declared more than once.
+  C2() : this.named();
+              ^"
+    ;
+}
+extension type ET1(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor • = self::ET1|constructor#;
+  constructor tearoff • = self::ET1|constructor#_#new#tearOff;
+  constructor named = self::ET1|constructor#named;
+  constructor tearoff named = self::ET1|constructor#_#named#tearOff;
+}
+extension type ET2(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor named = self::ET2|constructor#named;
+  constructor tearoff named = self::ET2|constructor#_#named#tearOff;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static extension-type-member method ET1|constructor#(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#new#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#(i);
+static extension-type-member method ET1|constructor#named(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_duplicate.dart:19:22: Error: Can't use 'new' because it is declared more than once.
+  ET1.named(int i) : this(i);
+                     ^";
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#named#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#named(i);
+static extension-type-member method ET2|constructor#named(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#named#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#named(i);
+static extension-type-member method ET2|constructor#(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_duplicate.dart:24:21: Error: Can't use 'named' because it is declared more than once.
+  ET2(int i) : this.named(i);
+                    ^";
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#new#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#(i);

pkg/front_end/testcases/general/redirect_to_duplicate.dart.textual_outline.expect

@@ -0,0 +1,21 @@
+class C1 {
+  C1();
+  C1();
+  C1.named() : this();
+}
+
+class C2 {
+  C2.named();
+  C2.named();
+  C2() : this.named();
+}
+
+extension type ET1(int i) {
+  ET1(this.i);
+  ET1.named(int i) : this(i);
+}
+
+extension type ET2.named(int i) {
+  ET2.named(this.i);
+  ET2(int i) : this.named(i);
+}

pkg/front_end/testcases/general/redirect_to_duplicate.dart.textual_outline_modelled.expect

@@ -0,0 +1,21 @@
+class C1 {
+  C1();
+  C1();
+  C1.named() : this();
+}
+
+class C2 {
+  C2() : this.named();
+  C2.named();
+  C2.named();
+}
+
+extension type ET1(int i) {
+  ET1(this.i);
+  ET1.named(int i) : this(i);
+}
+
+extension type ET2.named(int i) {
+  ET2(int i) : this.named(i);
+  ET2.named(this.i);
+}

pkg/front_end/testcases/general/redirect_to_factory.dart

@@ -0,0 +1,23 @@
+// Copyright (c) 2026, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class C1 {
+  factory C1() => throw '';
+  C1.named() : this();
+}
+
+class C2 {
+  factory C2.named() => throw '';
+  C2() : this.named();
+}
+
+extension type ET1.named(int i) {
+  factory ET1(int i) => throw '';
+  ET1(int i) : this(i);
+}
+
+extension type ET2.other(int i) {
+  factory ET2.named(int i) => throw '';
+  ET2(int i) : this.named(i);
+}

pkg/front_end/testcases/general/redirect_to_factory.dart.strong.expect

@@ -0,0 +1,95 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:17:3: Error: 'ET1' is already declared in this scope.
+//   ET1(int i) : this(i);
+//   ^^^
+// pkg/front_end/testcases/general/redirect_to_factory.dart:16:11: Context: Previous declaration of 'ET1'.
+//   factory ET1(int i) => throw '';
+//           ^^^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:7:16: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   C1.named() : this();
+//                ^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:12:15: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   C2() : this.named();
+//               ^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:22:21: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   ET2(int i) : this.named(i);
+//                     ^
+//
+import self as self;
+import "dart:core" as core;
+
+class C1 extends core::Object {
+  constructor named() → self::C1
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_factory.dart:7:16: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  C1.named() : this();
+               ^"
+    ;
+  static factory •() → self::C1
+    return throw "";
+}
+class C2 extends core::Object {
+  constructor •() → self::C2
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_factory.dart:12:15: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  C2() : this.named();
+              ^"
+    ;
+  static factory named() → self::C2
+    return throw "";
+}
+extension type ET1(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor named = self::ET1|constructor#named;
+  constructor tearoff named = self::ET1|constructor#_#named#tearOff;
+  static factory • = self::ET1|constructor#;
+  static factory tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor other = self::ET2|constructor#other;
+  constructor tearoff other = self::ET2|constructor#_#other#tearOff;
+  static factory named = self::ET2|constructor#named;
+  static factory tearoff named = self::ET2|constructor#_#named#tearOff;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static extension-type-member method ET1|constructor#named(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#named#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#named(i);
+static extension-type-member method ET1|constructor#(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return throw "";
+static extension-type-member synthetic method ET1|constructor#_#new#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#(i);
+static extension-type-member method ET2|constructor#other(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#other#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#other(i);
+static extension-type-member method ET2|constructor#named(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return throw "";
+static extension-type-member synthetic method ET2|constructor#_#named#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#named(i);
+static extension-type-member method ET2|constructor#(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_factory.dart:22:21: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  ET2(int i) : this.named(i);
+                    ^";
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#new#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#(i);

pkg/front_end/testcases/general/redirect_to_factory.dart.strong.modular.expect

@@ -0,0 +1,95 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:17:3: Error: 'ET1' is already declared in this scope.
+//   ET1(int i) : this(i);
+//   ^^^
+// pkg/front_end/testcases/general/redirect_to_factory.dart:16:11: Context: Previous declaration of 'ET1'.
+//   factory ET1(int i) => throw '';
+//           ^^^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:7:16: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   C1.named() : this();
+//                ^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:12:15: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   C2() : this.named();
+//               ^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:22:21: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   ET2(int i) : this.named(i);
+//                     ^
+//
+import self as self;
+import "dart:core" as core;
+
+class C1 extends core::Object {
+  constructor named() → self::C1
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_factory.dart:7:16: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  C1.named() : this();
+               ^"
+    ;
+  static factory •() → self::C1
+    return throw "";
+}
+class C2 extends core::Object {
+  constructor •() → self::C2
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_factory.dart:12:15: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  C2() : this.named();
+              ^"
+    ;
+  static factory named() → self::C2
+    return throw "";
+}
+extension type ET1(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor named = self::ET1|constructor#named;
+  constructor tearoff named = self::ET1|constructor#_#named#tearOff;
+  static factory • = self::ET1|constructor#;
+  static factory tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor other = self::ET2|constructor#other;
+  constructor tearoff other = self::ET2|constructor#_#other#tearOff;
+  static factory named = self::ET2|constructor#named;
+  static factory tearoff named = self::ET2|constructor#_#named#tearOff;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static extension-type-member method ET1|constructor#named(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#named#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#named(i);
+static extension-type-member method ET1|constructor#(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return throw "";
+static extension-type-member synthetic method ET1|constructor#_#new#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#(i);
+static extension-type-member method ET2|constructor#other(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#other#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#other(i);
+static extension-type-member method ET2|constructor#named(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return throw "";
+static extension-type-member synthetic method ET2|constructor#_#named#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#named(i);
+static extension-type-member method ET2|constructor#(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_factory.dart:22:21: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  ET2(int i) : this.named(i);
+                    ^";
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#new#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#(i);

pkg/front_end/testcases/general/redirect_to_factory.dart.strong.outline.expect

@@ -0,0 +1,62 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:17:3: Error: 'ET1' is already declared in this scope.
+//   ET1(int i) : this(i);
+//   ^^^
+// pkg/front_end/testcases/general/redirect_to_factory.dart:16:11: Context: Previous declaration of 'ET1'.
+//   factory ET1(int i) => throw '';
+//           ^^^
+//
+import self as self;
+import "dart:core" as core;
+
+class C1 extends core::Object {
+  constructor named() → self::C1
+    ;
+  static factory •() → self::C1
+    ;
+}
+class C2 extends core::Object {
+  constructor •() → self::C2
+    ;
+  static factory named() → self::C2
+    ;
+}
+extension type ET1(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor named = self::ET1|constructor#named;
+  constructor tearoff named = self::ET1|constructor#_#named#tearOff;
+  static factory • = self::ET1|constructor#;
+  static factory tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor other = self::ET2|constructor#other;
+  constructor tearoff other = self::ET2|constructor#_#other#tearOff;
+  static factory named = self::ET2|constructor#named;
+  static factory tearoff named = self::ET2|constructor#_#named#tearOff;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static extension-type-member method ET1|constructor#named(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET1|constructor#_#named#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#named(i);
+static extension-type-member method ET1|constructor#(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET1|constructor#_#new#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#(i);
+static extension-type-member method ET2|constructor#other(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET2|constructor#_#other#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#other(i);
+static extension-type-member method ET2|constructor#named(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET2|constructor#_#named#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#named(i);
+static extension-type-member method ET2|constructor#(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  ;
+static extension-type-member synthetic method ET2|constructor#_#new#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#(i);

pkg/front_end/testcases/general/redirect_to_factory.dart.strong.transformed.expect

@@ -0,0 +1,95 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:17:3: Error: 'ET1' is already declared in this scope.
+//   ET1(int i) : this(i);
+//   ^^^
+// pkg/front_end/testcases/general/redirect_to_factory.dart:16:11: Context: Previous declaration of 'ET1'.
+//   factory ET1(int i) => throw '';
+//           ^^^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:7:16: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   C1.named() : this();
+//                ^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:12:15: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   C2() : this.named();
+//               ^
+//
+// pkg/front_end/testcases/general/redirect_to_factory.dart:22:21: Error: Generative constructors can't redirect to a factory constructor.
+// Try redirecting to a different constructor.
+//   ET2(int i) : this.named(i);
+//                     ^
+//
+import self as self;
+import "dart:core" as core;
+
+class C1 extends core::Object {
+  constructor named() → self::C1
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_factory.dart:7:16: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  C1.named() : this();
+               ^"
+    ;
+  static factory •() → self::C1
+    return throw "";
+}
+class C2 extends core::Object {
+  constructor •() → self::C2
+    : invalid-initializer "pkg/front_end/testcases/general/redirect_to_factory.dart:12:15: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  C2() : this.named();
+              ^"
+    ;
+  static factory named() → self::C2
+    return throw "";
+}
+extension type ET1(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor named = self::ET1|constructor#named;
+  constructor tearoff named = self::ET1|constructor#_#named#tearOff;
+  static factory • = self::ET1|constructor#;
+  static factory tearoff • = self::ET1|constructor#_#new#tearOff;
+}
+extension type ET2(core::int i) {
+  abstract extension-type-member representation-field get i() → core::int;
+  constructor other = self::ET2|constructor#other;
+  constructor tearoff other = self::ET2|constructor#_#other#tearOff;
+  static factory named = self::ET2|constructor#named;
+  static factory tearoff named = self::ET2|constructor#_#named#tearOff;
+  constructor • = self::ET2|constructor#;
+  constructor tearoff • = self::ET2|constructor#_#new#tearOff;
+}
+static extension-type-member method ET1|constructor#named(core::int i) → self::ET1% /* erasure=core::int, declared=! */ {
+  lowered final self::ET1% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET1|constructor#_#named#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#named(i);
+static extension-type-member method ET1|constructor#(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return throw "";
+static extension-type-member synthetic method ET1|constructor#_#new#tearOff(core::int i) → self::ET1% /* erasure=core::int, declared=! */
+  return self::ET1|constructor#(i);
+static extension-type-member method ET2|constructor#other(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this = i;
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#other#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#other(i);
+static extension-type-member method ET2|constructor#named(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return throw "";
+static extension-type-member synthetic method ET2|constructor#_#named#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#named(i);
+static extension-type-member method ET2|constructor#(core::int i) → self::ET2% /* erasure=core::int, declared=! */ {
+  lowered final self::ET2% /* erasure=core::int, declared=! */ #this;
+  invalid-expression "pkg/front_end/testcases/general/redirect_to_factory.dart:22:21: Error: Generative constructors can't redirect to a factory constructor.
+Try redirecting to a different constructor.
+  ET2(int i) : this.named(i);
+                    ^";
+  return #this;
+}
+static extension-type-member synthetic method ET2|constructor#_#new#tearOff(core::int i) → self::ET2% /* erasure=core::int, declared=! */
+  return self::ET2|constructor#(i);

pkg/front_end/testcases/general/redirect_to_factory.dart.textual_outline.expect

@@ -0,0 +1,19 @@
+class C1 {
+  factory C1() => throw '';
+  C1.named() : this();
+}
+
+class C2 {
+  factory C2.named() => throw '';
+  C2() : this.named();
+}
+
+extension type ET1.named(int i) {
+  factory ET1(int i) => throw '';
+  ET1(int i) : this(i);
+}
+
+extension type ET2.other(int i) {
+  factory ET2.named(int i) => throw '';
+  ET2(int i) : this.named(i);
+}

pkg/front_end/testcases/general/redirect_to_factory.dart.textual_outline_modelled.expect

@@ -0,0 +1,19 @@
+class C1 {
+  C1.named() : this();
+  factory C1() => throw '';
+}
+
+class C2 {
+  C2() : this.named();
+  factory C2.named() => throw '';
+}
+
+extension type ET1.named(int i) {
+  ET1(int i) : this(i);
+  factory ET1(int i) => throw '';
+}
+
+extension type ET2.other(int i) {
+  ET2(int i) : this.named(i);
+  factory ET2.named(int i) => throw '';
+}

pkg/front_end/testcases/primary_constructors/redirecting_error.dart.strong.expect

@@ -9,10 +9,6 @@ library;
 // class C5(var int v) {
 //         ^
 //
-// pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Couldn't find constructor 'C5'.
-//   C5.foo(int v) : this(v);
-//                   ^^^^
-//
 import self as self;
 import "dart:core" as core;
 
@@ -22,8 +18,8 @@ class C5 extends core::Object {
     : self::C5::v = v, super core::Object::•()
     ;
   constructor foo(core::int v) → self::C5
-    : invalid-initializer "pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Couldn't find constructor 'C5'.
+    : invalid-initializer "pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Can't use 'new' because it is declared more than once.
   C5.foo(int v) : this(v);
-                  ^^^^"
+                  ^"
     ;
 }

pkg/front_end/testcases/primary_constructors/redirecting_error.dart.strong.modular.expect

@@ -9,10 +9,6 @@ library;
 // class C5(var int v) {
 //         ^
 //
-// pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Couldn't find constructor 'C5'.
-//   C5.foo(int v) : this(v);
-//                   ^^^^
-//
 import self as self;
 import "dart:core" as core;
 
@@ -22,8 +18,8 @@ class C5 extends core::Object {
     : self::C5::v = v, super core::Object::•()
     ;
   constructor foo(core::int v) → self::C5
-    : invalid-initializer "pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Couldn't find constructor 'C5'.
+    : invalid-initializer "pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Can't use 'new' because it is declared more than once.
   C5.foo(int v) : this(v);
-                  ^^^^"
+                  ^"
     ;
 }

pkg/front_end/testcases/primary_constructors/redirecting_error.dart.strong.transformed.expect

@@ -9,10 +9,6 @@ library;
 // class C5(var int v) {
 //         ^
 //
-// pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Couldn't find constructor 'C5'.
-//   C5.foo(int v) : this(v);
-//                   ^^^^
-//
 import self as self;
 import "dart:core" as core;
 
@@ -22,8 +18,8 @@ class C5 extends core::Object {
     : self::C5::v = v, super core::Object::•()
     ;
   constructor foo(core::int v) → self::C5
-    : invalid-initializer "pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Couldn't find constructor 'C5'.
+    : invalid-initializer "pkg/front_end/testcases/primary_constructors/redirecting_error.dart:6:19: Error: Can't use 'new' because it is declared more than once.
   C5.foo(int v) : this(v);
-                  ^^^^"
+                  ^"
     ;
 }

tests/language/enum/enhanced_enums_error_test.dart

@@ -502,7 +502,7 @@ enum NoConstructorCalls {
   // [analyzer] COMPILE_TIME_ERROR.REDIRECT_GENERATIVE_TO_NON_GENERATIVE_CONSTRUCTOR
   //                                            ^^^^^^^
   // [analyzer] COMPILE_TIME_ERROR.REDIRECT_TO_NON_CONST_CONSTRUCTOR
-  // [cfe] Couldn't find constructor 'NoConstructorCalls.factory'.
+  // [cfe] Generative constructors can't redirect to a factory constructor.
 
   factory NoConstructorCalls.factory() => e1; // Valid.
 

tests/language/primary_constructors/header/constructor_name_error_test.dart

@@ -61,8 +61,6 @@ extension type ET2.named(int x) {
 
 class C3(int x) {
   C3.other(int x) : this(x);
-  //                ^
-  // [cfe] Couldn't find constructor 'C3'.
   factory C3(int x) => C3.other(x);
   //      ^^
   // [analyzer] COMPILE_TIME_ERROR.DUPLICATE_CONSTRUCTOR
@@ -71,8 +69,6 @@ class C3(int x) {
 
 class C4.named(int x) {
   C4.other(int x) : this.named(x);
-  //                     ^
-  // [cfe] Couldn't find constructor 'C4.named'.
   factory C4.named(int x) => C4.other(x);
   //      ^^^^^^^^
   // [analyzer] COMPILE_TIME_ERROR.DUPLICATE_CONSTRUCTOR