diff --git a/pkg/front_end/lib/src/fragment/field/encoding.dart b/pkg/front_end/lib/src/fragment/field/encoding.dart
index a6c9564ea70..4370d2784af 100644
--- a/pkg/front_end/lib/src/fragment/field/encoding.dart
+++ b/pkg/front_end/lib/src/fragment/field/encoding.dart
@@ -1205,6 +1205,7 @@ class RepresentationFieldEncoding implements FieldEncoding {
       {required bool isSynthetic}) {
     return <Initializer>[
       new ExtensionTypeRepresentationFieldInitializer(_getter, value)
+        ..fileOffset = fileOffset
     ];
   }
 
diff --git a/pkg/front_end/lib/src/kernel/body_builder.dart b/pkg/front_end/lib/src/kernel/body_builder.dart
index 4895bfa3a5a..28985dd30d4 100644
--- a/pkg/front_end/lib/src/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/kernel/body_builder.dart
@@ -98,6 +98,7 @@ import '../codes/cfe_codes.dart' as cfe;
 import '../dill/dill_library_builder.dart' show DillLibraryBuilder;
 import '../dill/dill_type_parameter_builder.dart';
 import '../fragment/fragment.dart';
+import '../source/constructor_declaration.dart';
 import '../source/diet_parser.dart';
 import '../source/offset_map.dart';
 import '../source/source_library_builder.dart';
@@ -9302,6 +9303,9 @@ class BodyBuilder extends StackListenerImpl
                 cfe.messageUnexpectedSuperParametersInGenerativeConstructors,
                 formal.fileOffset,
                 noLength);
+            if (constructorBuilder is ConstructorDeclarationBuilder) {
+              constructorBuilder.markAsErroneous();
+            }
           }
         }
       }
diff --git a/pkg/front_end/lib/src/source/source_constructor_builder.dart b/pkg/front_end/lib/src/source/source_constructor_builder.dart
index 0236ffe2f90..6084472529b 100644
--- a/pkg/front_end/lib/src/source/source_constructor_builder.dart
+++ b/pkg/front_end/lib/src/source/source_constructor_builder.dart
@@ -456,7 +456,15 @@ class SourceConstructorBuilderImpl extends SourceMemberBuilderImpl
           _initializers.add(initializer..parent = parent);
         }
       }
-    } else if (initializer is RedirectingInitializer) {
+    } else if (initializer
+        case RedirectingInitializer(
+              target: Member initializerTarget,
+              arguments: var initializerArguments
+            ) ||
+            ExtensionTypeRedirectingInitializer(
+              target: Member initializerTarget,
+              arguments: var initializerArguments
+            )) {
       if (superInitializer != null) {
         // Point to the existing super initializer.
         _injectInvalidInitializer(
@@ -465,6 +473,7 @@ class SourceConstructorBuilderImpl extends SourceMemberBuilderImpl
             "super".length,
             helper,
             parent);
+        markAsErroneous();
       } else if (redirectingInitializer != null) {
         _injectInvalidInitializer(
             messageRedirectingConstructorWithMultipleRedirectInitializers,
@@ -472,6 +481,7 @@ class SourceConstructorBuilderImpl extends SourceMemberBuilderImpl
             noLength,
             helper,
             parent);
+        markAsErroneous();
       } else if (_initializers.isNotEmpty) {
         // Error on all previous ones.
         for (int i = 0; i < _initializers.length; i++) {
@@ -488,22 +498,30 @@ class SourceConstructorBuilderImpl extends SourceMemberBuilderImpl
         }
         inferenceResult?.applyResult(_initializers, parent);
         _initializers.add(initializer..parent = parent);
-        redirectingInitializer = initializer;
+        if (initializer is RedirectingInitializer) {
+          redirectingInitializer = initializer;
+        }
+        markAsErroneous();
       } else {
         inferenceResult?.applyResult(_initializers, parent);
-        redirectingInitializer = initializer;
+        if (initializer is RedirectingInitializer) {
+          redirectingInitializer = initializer;
+        }
 
         LocatedMessage? message = helper.checkArgumentsForFunction(
-            initializer.target.function,
-            initializer.arguments,
-            initializer.arguments.fileOffset, const <TypeParameter>[]);
+            initializerTarget.function!,
+            initializerArguments,
+            initializerArguments.fileOffset,
+            initializer is ExtensionTypeRedirectingInitializer
+                ? initializerTarget.function!.typeParameters
+                : const <TypeParameter>[]);
         if (message != null) {
           _initializers.add(helper.buildInvalidInitializer(
               helper.buildUnresolvedError(
                   helper.constructorNameForDiagnostics(
-                      initializer.target.name.text),
+                      initializerTarget.name.text),
                   initializer.fileOffset,
-                  arguments: initializer.arguments,
+                  arguments: initializerArguments,
                   isSuper: false,
                   message: message,
                   kind: UnresolvedKind.Constructor))
@@ -522,9 +540,11 @@ class SourceConstructorBuilderImpl extends SourceMemberBuilderImpl
           length,
           helper,
           parent);
+      markAsErroneous();
     } else if (superInitializer != null) {
       _injectInvalidInitializer(messageSuperInitializerNotLast,
           initializer.fileOffset, noLength, helper, parent);
+      markAsErroneous();
     } else {
       inferenceResult?.applyResult(_initializers, parent);
       _initializers.add(initializer..parent = parent);
diff --git a/pkg/front_end/test/predicates/data/extension_type.dart b/pkg/front_end/test/predicates/data/extension_type.dart
index 6bffecaa518..43502ec8675 100644
--- a/pkg/front_end/test/predicates/data/extension_type.dart
+++ b/pkg/front_end/test/predicates/data/extension_type.dart
@@ -3,9 +3,15 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*member: ExtensionType|constructor#:extensionName=ExtensionType.new*/
-extension type ExtensionType(int it) {
+extension type ExtensionType(int /*
+ extensionThis,
+ name=this
+*/it) {
   /*member: ExtensionType|constructor#constructor:extensionName=ExtensionType.constructor*/
-  ExtensionType.constructor(this.it);
+  ExtensionType.constructor(this./*
+   extensionThis,
+   name=this
+  */it);
 
   /*member: ExtensionType|constructor#factory:extensionName=ExtensionType.factory*/
   factory ExtensionType.factory(int value) => ExtensionType(value);
diff --git a/pkg/front_end/testcases/extension_types/erroneous_constructors.dart b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart
new file mode 100644
index 00000000000..09fccdd311e
--- /dev/null
+++ b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart
@@ -0,0 +1,19 @@
+// Copyright (c) 2025, 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 E1(dynamic it) {
+  E1.named(dynamic value) : this(value, value);
+}
+
+extension type E2(num it) {
+  E2.named(super.it) : this(it);
+}
+
+extension type E3(String it) {
+  E3.named(String it1, String it2) : this(it1), this(it2);
+}
+
+extension type E4(bool it) {
+  E4.named(bool it) : it = false, this(it);
+}
diff --git a/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.expect b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.expect
new file mode 100644
index 00000000000..4b98272e8f8
--- /dev/null
+++ b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.expect
@@ -0,0 +1,116 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:10:18: Error: Extension type constructors can't declare super formal parameters.
+//   E2.named(super.it) : this(it);
+//                  ^^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:10:18: Error: Super parameters can only be used in non-redirecting generative constructors.
+//   E2.named(super.it) : this(it);
+//                  ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:6:33: Error: Too many positional arguments: 1 allowed, but 2 found.
+// Try removing the extra positional arguments.
+//   E1.named(dynamic value) : this(value, value);
+//                                 ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:14:38: Error: A redirecting constructor can't have other initializers.
+//   E3.named(String it1, String it2) : this(it1), this(it2);
+//                                      ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:18:26: Error: A redirecting constructor can't have other initializers.
+//   E4.named(bool it) : it = false, this(it);
+//                          ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type E1(dynamic it) {
+  abstract extension-type-member representation-field get it() → dynamic;
+  constructor • = self::E1|constructor#;
+  constructor tearoff • = self::E1|constructor#_#new#tearOff;
+  constructor named = self::E1|constructor#named;
+  constructor tearoff named = self::E1|constructor#_#named#tearOff;
+}
+extension type E2(core::num it) {
+  abstract extension-type-member representation-field get it() → core::num;
+  constructor • = self::E2|constructor#;
+  constructor tearoff • = self::E2|constructor#_#new#tearOff;
+  constructor named = self::E2|constructor#named;
+  constructor tearoff named = self::E2|constructor#_#named#tearOff;
+}
+extension type E3(core::String it) {
+  abstract extension-type-member representation-field get it() → core::String;
+  constructor • = self::E3|constructor#;
+  constructor tearoff • = self::E3|constructor#_#new#tearOff;
+  constructor named = self::E3|constructor#named;
+  constructor tearoff named = self::E3|constructor#_#named#tearOff;
+}
+extension type E4(core::bool it) {
+  abstract extension-type-member representation-field get it() → core::bool;
+  constructor • = self::E4|constructor#;
+  constructor tearoff • = self::E4|constructor#_#new#tearOff;
+  constructor named = self::E4|constructor#named;
+  constructor tearoff named = self::E4|constructor#_#named#tearOff;
+}
+static extension-type-member method E1|constructor#(dynamic it) → self::E1% /* erasure=dynamic, declared=! */ {
+  lowered final self::E1% /* erasure=dynamic, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E1|constructor#_#new#tearOff(dynamic it) → self::E1% /* erasure=dynamic, declared=! */
+  return self::E1|constructor#(it);
+static extension-type-member erroneous method E1|constructor#named(dynamic value) → self::E1% /* erasure=dynamic, declared=! */ {
+  lowered final self::E1% /* erasure=dynamic, declared=! */ #this;
+  final dynamic #t1 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:6:33: Error: Too many positional arguments: 1 allowed, but 2 found.
+Try removing the extra positional arguments.
+  E1.named(dynamic value) : this(value, value);
+                                ^";
+  return #this;
+}
+static extension-type-member synthetic method E1|constructor#_#named#tearOff(dynamic value) → self::E1% /* erasure=dynamic, declared=! */
+  return self::E1|constructor#named(value);
+static extension-type-member erroneous method E2|constructor#(core::num it) → self::E2% /* erasure=core::num, declared=! */ {
+  lowered final self::E2% /* erasure=core::num, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E2|constructor#_#new#tearOff(core::num it) → self::E2% /* erasure=core::num, declared=! */
+  return self::E2|constructor#(it);
+static extension-type-member method E2|constructor#named(invalid-type it) → self::E2% /* erasure=core::num, declared=! */ {
+  lowered final self::E2% /* erasure=core::num, declared=! */ #this;
+  return #this;
+}
+static extension-type-member synthetic method E2|constructor#_#named#tearOff(invalid-type it) → self::E2% /* erasure=core::num, declared=! */
+  return self::E2|constructor#named(it);
+static extension-type-member method E3|constructor#(core::String it) → self::E3% /* erasure=core::String, declared=! */ {
+  lowered final self::E3% /* erasure=core::String, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E3|constructor#_#new#tearOff(core::String it) → self::E3% /* erasure=core::String, declared=! */
+  return self::E3|constructor#(it);
+static extension-type-member erroneous method E3|constructor#named(core::String it1, core::String it2) → self::E3% /* erasure=core::String, declared=! */ {
+  lowered final self::E3% /* erasure=core::String, declared=! */ #this;
+  final dynamic #t2 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:14:38: Error: A redirecting constructor can't have other initializers.
+  E3.named(String it1, String it2) : this(it1), this(it2);
+                                     ^";
+  #this = self::E3|constructor#(it2);
+  return #this;
+}
+static extension-type-member synthetic method E3|constructor#_#named#tearOff(core::String it1, core::String it2) → self::E3% /* erasure=core::String, declared=! */
+  return self::E3|constructor#named(it1, it2);
+static extension-type-member method E4|constructor#(core::bool it) → self::E4% /* erasure=core::bool, declared=! */ {
+  lowered final self::E4% /* erasure=core::bool, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E4|constructor#_#new#tearOff(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  return self::E4|constructor#(it);
+static extension-type-member erroneous method E4|constructor#named(core::bool it) → self::E4% /* erasure=core::bool, declared=! */ {
+  lowered final self::E4% /* erasure=core::bool, declared=! */ #this;
+  final dynamic #t3 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:18:26: Error: A redirecting constructor can't have other initializers.
+  E4.named(bool it) : it = false, this(it);
+                         ^";
+  #this = self::E4|constructor#(it);
+  return #this;
+}
+static extension-type-member synthetic method E4|constructor#_#named#tearOff(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  return self::E4|constructor#named(it);
diff --git a/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.modular.expect b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.modular.expect
new file mode 100644
index 00000000000..4b98272e8f8
--- /dev/null
+++ b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.modular.expect
@@ -0,0 +1,116 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:10:18: Error: Extension type constructors can't declare super formal parameters.
+//   E2.named(super.it) : this(it);
+//                  ^^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:10:18: Error: Super parameters can only be used in non-redirecting generative constructors.
+//   E2.named(super.it) : this(it);
+//                  ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:6:33: Error: Too many positional arguments: 1 allowed, but 2 found.
+// Try removing the extra positional arguments.
+//   E1.named(dynamic value) : this(value, value);
+//                                 ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:14:38: Error: A redirecting constructor can't have other initializers.
+//   E3.named(String it1, String it2) : this(it1), this(it2);
+//                                      ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:18:26: Error: A redirecting constructor can't have other initializers.
+//   E4.named(bool it) : it = false, this(it);
+//                          ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type E1(dynamic it) {
+  abstract extension-type-member representation-field get it() → dynamic;
+  constructor • = self::E1|constructor#;
+  constructor tearoff • = self::E1|constructor#_#new#tearOff;
+  constructor named = self::E1|constructor#named;
+  constructor tearoff named = self::E1|constructor#_#named#tearOff;
+}
+extension type E2(core::num it) {
+  abstract extension-type-member representation-field get it() → core::num;
+  constructor • = self::E2|constructor#;
+  constructor tearoff • = self::E2|constructor#_#new#tearOff;
+  constructor named = self::E2|constructor#named;
+  constructor tearoff named = self::E2|constructor#_#named#tearOff;
+}
+extension type E3(core::String it) {
+  abstract extension-type-member representation-field get it() → core::String;
+  constructor • = self::E3|constructor#;
+  constructor tearoff • = self::E3|constructor#_#new#tearOff;
+  constructor named = self::E3|constructor#named;
+  constructor tearoff named = self::E3|constructor#_#named#tearOff;
+}
+extension type E4(core::bool it) {
+  abstract extension-type-member representation-field get it() → core::bool;
+  constructor • = self::E4|constructor#;
+  constructor tearoff • = self::E4|constructor#_#new#tearOff;
+  constructor named = self::E4|constructor#named;
+  constructor tearoff named = self::E4|constructor#_#named#tearOff;
+}
+static extension-type-member method E1|constructor#(dynamic it) → self::E1% /* erasure=dynamic, declared=! */ {
+  lowered final self::E1% /* erasure=dynamic, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E1|constructor#_#new#tearOff(dynamic it) → self::E1% /* erasure=dynamic, declared=! */
+  return self::E1|constructor#(it);
+static extension-type-member erroneous method E1|constructor#named(dynamic value) → self::E1% /* erasure=dynamic, declared=! */ {
+  lowered final self::E1% /* erasure=dynamic, declared=! */ #this;
+  final dynamic #t1 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:6:33: Error: Too many positional arguments: 1 allowed, but 2 found.
+Try removing the extra positional arguments.
+  E1.named(dynamic value) : this(value, value);
+                                ^";
+  return #this;
+}
+static extension-type-member synthetic method E1|constructor#_#named#tearOff(dynamic value) → self::E1% /* erasure=dynamic, declared=! */
+  return self::E1|constructor#named(value);
+static extension-type-member erroneous method E2|constructor#(core::num it) → self::E2% /* erasure=core::num, declared=! */ {
+  lowered final self::E2% /* erasure=core::num, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E2|constructor#_#new#tearOff(core::num it) → self::E2% /* erasure=core::num, declared=! */
+  return self::E2|constructor#(it);
+static extension-type-member method E2|constructor#named(invalid-type it) → self::E2% /* erasure=core::num, declared=! */ {
+  lowered final self::E2% /* erasure=core::num, declared=! */ #this;
+  return #this;
+}
+static extension-type-member synthetic method E2|constructor#_#named#tearOff(invalid-type it) → self::E2% /* erasure=core::num, declared=! */
+  return self::E2|constructor#named(it);
+static extension-type-member method E3|constructor#(core::String it) → self::E3% /* erasure=core::String, declared=! */ {
+  lowered final self::E3% /* erasure=core::String, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E3|constructor#_#new#tearOff(core::String it) → self::E3% /* erasure=core::String, declared=! */
+  return self::E3|constructor#(it);
+static extension-type-member erroneous method E3|constructor#named(core::String it1, core::String it2) → self::E3% /* erasure=core::String, declared=! */ {
+  lowered final self::E3% /* erasure=core::String, declared=! */ #this;
+  final dynamic #t2 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:14:38: Error: A redirecting constructor can't have other initializers.
+  E3.named(String it1, String it2) : this(it1), this(it2);
+                                     ^";
+  #this = self::E3|constructor#(it2);
+  return #this;
+}
+static extension-type-member synthetic method E3|constructor#_#named#tearOff(core::String it1, core::String it2) → self::E3% /* erasure=core::String, declared=! */
+  return self::E3|constructor#named(it1, it2);
+static extension-type-member method E4|constructor#(core::bool it) → self::E4% /* erasure=core::bool, declared=! */ {
+  lowered final self::E4% /* erasure=core::bool, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E4|constructor#_#new#tearOff(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  return self::E4|constructor#(it);
+static extension-type-member erroneous method E4|constructor#named(core::bool it) → self::E4% /* erasure=core::bool, declared=! */ {
+  lowered final self::E4% /* erasure=core::bool, declared=! */ #this;
+  final dynamic #t3 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:18:26: Error: A redirecting constructor can't have other initializers.
+  E4.named(bool it) : it = false, this(it);
+                         ^";
+  #this = self::E4|constructor#(it);
+  return #this;
+}
+static extension-type-member synthetic method E4|constructor#_#named#tearOff(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  return self::E4|constructor#named(it);
diff --git a/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.outline.expect b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.outline.expect
new file mode 100644
index 00000000000..ae16c6f6756
--- /dev/null
+++ b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.outline.expect
@@ -0,0 +1,77 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:10:18: Error: Extension type constructors can't declare super formal parameters.
+//   E2.named(super.it) : this(it);
+//                  ^^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:10:18: Error: Super parameters can only be used in non-redirecting generative constructors.
+//   E2.named(super.it) : this(it);
+//                  ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type E1(dynamic it) {
+  abstract extension-type-member representation-field get it() → dynamic;
+  constructor • = self::E1|constructor#;
+  constructor tearoff • = self::E1|constructor#_#new#tearOff;
+  constructor named = self::E1|constructor#named;
+  constructor tearoff named = self::E1|constructor#_#named#tearOff;
+}
+extension type E2(core::num it) {
+  abstract extension-type-member representation-field get it() → core::num;
+  constructor • = self::E2|constructor#;
+  constructor tearoff • = self::E2|constructor#_#new#tearOff;
+  constructor named = self::E2|constructor#named;
+  constructor tearoff named = self::E2|constructor#_#named#tearOff;
+}
+extension type E3(core::String it) {
+  abstract extension-type-member representation-field get it() → core::String;
+  constructor • = self::E3|constructor#;
+  constructor tearoff • = self::E3|constructor#_#new#tearOff;
+  constructor named = self::E3|constructor#named;
+  constructor tearoff named = self::E3|constructor#_#named#tearOff;
+}
+extension type E4(core::bool it) {
+  abstract extension-type-member representation-field get it() → core::bool;
+  constructor • = self::E4|constructor#;
+  constructor tearoff • = self::E4|constructor#_#new#tearOff;
+  constructor named = self::E4|constructor#named;
+  constructor tearoff named = self::E4|constructor#_#named#tearOff;
+}
+static extension-type-member method E1|constructor#(dynamic it) → self::E1% /* erasure=dynamic, declared=! */
+  ;
+static extension-type-member synthetic method E1|constructor#_#new#tearOff(dynamic it) → self::E1% /* erasure=dynamic, declared=! */
+  return self::E1|constructor#(it);
+static extension-type-member method E1|constructor#named(dynamic value) → self::E1% /* erasure=dynamic, declared=! */
+  ;
+static extension-type-member synthetic method E1|constructor#_#named#tearOff(dynamic value) → self::E1% /* erasure=dynamic, declared=! */
+  return self::E1|constructor#named(value);
+static extension-type-member erroneous method E2|constructor#(core::num it) → self::E2% /* erasure=core::num, declared=! */
+  ;
+static extension-type-member synthetic method E2|constructor#_#new#tearOff(core::num it) → self::E2% /* erasure=core::num, declared=! */
+  return self::E2|constructor#(it);
+static extension-type-member method E2|constructor#named(invalid-type it) → self::E2% /* erasure=core::num, declared=! */ {
+  lowered final self::E2% /* erasure=core::num, declared=! */ #this;
+  return #this;
+}
+static extension-type-member synthetic method E2|constructor#_#named#tearOff(invalid-type it) → self::E2% /* erasure=core::num, declared=! */
+  return self::E2|constructor#named(it);
+static extension-type-member method E3|constructor#(core::String it) → self::E3% /* erasure=core::String, declared=! */
+  ;
+static extension-type-member synthetic method E3|constructor#_#new#tearOff(core::String it) → self::E3% /* erasure=core::String, declared=! */
+  return self::E3|constructor#(it);
+static extension-type-member method E3|constructor#named(core::String it1, core::String it2) → self::E3% /* erasure=core::String, declared=! */
+  ;
+static extension-type-member synthetic method E3|constructor#_#named#tearOff(core::String it1, core::String it2) → self::E3% /* erasure=core::String, declared=! */
+  return self::E3|constructor#named(it1, it2);
+static extension-type-member method E4|constructor#(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  ;
+static extension-type-member synthetic method E4|constructor#_#new#tearOff(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  return self::E4|constructor#(it);
+static extension-type-member method E4|constructor#named(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  ;
+static extension-type-member synthetic method E4|constructor#_#named#tearOff(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  return self::E4|constructor#named(it);
diff --git a/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.transformed.expect b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.transformed.expect
new file mode 100644
index 00000000000..4b98272e8f8
--- /dev/null
+++ b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.strong.transformed.expect
@@ -0,0 +1,116 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:10:18: Error: Extension type constructors can't declare super formal parameters.
+//   E2.named(super.it) : this(it);
+//                  ^^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:10:18: Error: Super parameters can only be used in non-redirecting generative constructors.
+//   E2.named(super.it) : this(it);
+//                  ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:6:33: Error: Too many positional arguments: 1 allowed, but 2 found.
+// Try removing the extra positional arguments.
+//   E1.named(dynamic value) : this(value, value);
+//                                 ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:14:38: Error: A redirecting constructor can't have other initializers.
+//   E3.named(String it1, String it2) : this(it1), this(it2);
+//                                      ^
+//
+// pkg/front_end/testcases/extension_types/erroneous_constructors.dart:18:26: Error: A redirecting constructor can't have other initializers.
+//   E4.named(bool it) : it = false, this(it);
+//                          ^
+//
+import self as self;
+import "dart:core" as core;
+
+extension type E1(dynamic it) {
+  abstract extension-type-member representation-field get it() → dynamic;
+  constructor • = self::E1|constructor#;
+  constructor tearoff • = self::E1|constructor#_#new#tearOff;
+  constructor named = self::E1|constructor#named;
+  constructor tearoff named = self::E1|constructor#_#named#tearOff;
+}
+extension type E2(core::num it) {
+  abstract extension-type-member representation-field get it() → core::num;
+  constructor • = self::E2|constructor#;
+  constructor tearoff • = self::E2|constructor#_#new#tearOff;
+  constructor named = self::E2|constructor#named;
+  constructor tearoff named = self::E2|constructor#_#named#tearOff;
+}
+extension type E3(core::String it) {
+  abstract extension-type-member representation-field get it() → core::String;
+  constructor • = self::E3|constructor#;
+  constructor tearoff • = self::E3|constructor#_#new#tearOff;
+  constructor named = self::E3|constructor#named;
+  constructor tearoff named = self::E3|constructor#_#named#tearOff;
+}
+extension type E4(core::bool it) {
+  abstract extension-type-member representation-field get it() → core::bool;
+  constructor • = self::E4|constructor#;
+  constructor tearoff • = self::E4|constructor#_#new#tearOff;
+  constructor named = self::E4|constructor#named;
+  constructor tearoff named = self::E4|constructor#_#named#tearOff;
+}
+static extension-type-member method E1|constructor#(dynamic it) → self::E1% /* erasure=dynamic, declared=! */ {
+  lowered final self::E1% /* erasure=dynamic, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E1|constructor#_#new#tearOff(dynamic it) → self::E1% /* erasure=dynamic, declared=! */
+  return self::E1|constructor#(it);
+static extension-type-member erroneous method E1|constructor#named(dynamic value) → self::E1% /* erasure=dynamic, declared=! */ {
+  lowered final self::E1% /* erasure=dynamic, declared=! */ #this;
+  final dynamic #t1 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:6:33: Error: Too many positional arguments: 1 allowed, but 2 found.
+Try removing the extra positional arguments.
+  E1.named(dynamic value) : this(value, value);
+                                ^";
+  return #this;
+}
+static extension-type-member synthetic method E1|constructor#_#named#tearOff(dynamic value) → self::E1% /* erasure=dynamic, declared=! */
+  return self::E1|constructor#named(value);
+static extension-type-member erroneous method E2|constructor#(core::num it) → self::E2% /* erasure=core::num, declared=! */ {
+  lowered final self::E2% /* erasure=core::num, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E2|constructor#_#new#tearOff(core::num it) → self::E2% /* erasure=core::num, declared=! */
+  return self::E2|constructor#(it);
+static extension-type-member method E2|constructor#named(invalid-type it) → self::E2% /* erasure=core::num, declared=! */ {
+  lowered final self::E2% /* erasure=core::num, declared=! */ #this;
+  return #this;
+}
+static extension-type-member synthetic method E2|constructor#_#named#tearOff(invalid-type it) → self::E2% /* erasure=core::num, declared=! */
+  return self::E2|constructor#named(it);
+static extension-type-member method E3|constructor#(core::String it) → self::E3% /* erasure=core::String, declared=! */ {
+  lowered final self::E3% /* erasure=core::String, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E3|constructor#_#new#tearOff(core::String it) → self::E3% /* erasure=core::String, declared=! */
+  return self::E3|constructor#(it);
+static extension-type-member erroneous method E3|constructor#named(core::String it1, core::String it2) → self::E3% /* erasure=core::String, declared=! */ {
+  lowered final self::E3% /* erasure=core::String, declared=! */ #this;
+  final dynamic #t2 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:14:38: Error: A redirecting constructor can't have other initializers.
+  E3.named(String it1, String it2) : this(it1), this(it2);
+                                     ^";
+  #this = self::E3|constructor#(it2);
+  return #this;
+}
+static extension-type-member synthetic method E3|constructor#_#named#tearOff(core::String it1, core::String it2) → self::E3% /* erasure=core::String, declared=! */
+  return self::E3|constructor#named(it1, it2);
+static extension-type-member method E4|constructor#(core::bool it) → self::E4% /* erasure=core::bool, declared=! */ {
+  lowered final self::E4% /* erasure=core::bool, declared=! */ #this = it;
+  return #this;
+}
+static extension-type-member synthetic method E4|constructor#_#new#tearOff(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  return self::E4|constructor#(it);
+static extension-type-member erroneous method E4|constructor#named(core::bool it) → self::E4% /* erasure=core::bool, declared=! */ {
+  lowered final self::E4% /* erasure=core::bool, declared=! */ #this;
+  final dynamic #t3 = invalid-expression "pkg/front_end/testcases/extension_types/erroneous_constructors.dart:18:26: Error: A redirecting constructor can't have other initializers.
+  E4.named(bool it) : it = false, this(it);
+                         ^";
+  #this = self::E4|constructor#(it);
+  return #this;
+}
+static extension-type-member synthetic method E4|constructor#_#named#tearOff(core::bool it) → self::E4% /* erasure=core::bool, declared=! */
+  return self::E4|constructor#named(it);
diff --git a/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.textual_outline.expect b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.textual_outline.expect
new file mode 100644
index 00000000000..5489a7e57d3
--- /dev/null
+++ b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.textual_outline.expect
@@ -0,0 +1,19 @@
+extension type E1(dynamic it) {
+  E1.named(dynamic value) : this(value, value);
+}
+
+extension type E2(num it) {
+  E2.named(super.it) : this(it);
+}
+
+extension type E3(String it) {
+  E3.named(String it1, String it2)
+      : this(it1),
+        this(it2);
+}
+
+extension type E4(bool it) {
+  E4.named(bool it)
+      : it = false,
+        this(it);
+}
diff --git a/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.textual_outline_modelled.expect
new file mode 100644
index 00000000000..5489a7e57d3
--- /dev/null
+++ b/pkg/front_end/testcases/extension_types/erroneous_constructors.dart.textual_outline_modelled.expect
@@ -0,0 +1,19 @@
+extension type E1(dynamic it) {
+  E1.named(dynamic value) : this(value, value);
+}
+
+extension type E2(num it) {
+  E2.named(super.it) : this(it);
+}
+
+extension type E3(String it) {
+  E3.named(String it1, String it2)
+      : this(it1),
+        this(it2);
+}
+
+extension type E4(bool it) {
+  E4.named(bool it)
+      : it = false,
+        this(it);
+}
diff --git a/pkg/front_end/testcases/general/initialization_errors.dart.strong.expect b/pkg/front_end/testcases/general/initialization_errors.dart.strong.expect
index ea5e456680d..f935cd6dff7 100644
--- a/pkg/front_end/testcases/general/initialization_errors.dart.strong.expect
+++ b/pkg/front_end/testcases/general/initialization_errors.dart.strong.expect
@@ -124,7 +124,7 @@ class C extends core::Object {
 class D extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::D
+  erroneous constructor •() → self::D
     : final dynamic #t5 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:30:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 41,
                ^", final dynamic #t6 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:32:16: Error: A redirecting constructor can't have other initializers.
@@ -136,7 +136,7 @@ class D extends core::Object {
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::E
+  erroneous constructor •() → self::E
     : final dynamic #t7 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:43:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1,
                ^", final dynamic #t8 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:44:16: Error: A redirecting constructor can't have other initializers.
@@ -144,14 +144,14 @@ class E extends core::Object {
                ^", this self::E::named() {}
   constructor named() → self::E
     : self::E::x = 41, self::E::y = 42, super core::Object::•() {}
-  constructor named2() → self::E
+  erroneous constructor named2() → self::E
     : final dynamic #t9 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:49:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 1,
                ^", final dynamic #t10 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:51:16: Error: A redirecting constructor can't have other initializers.
         this.y = 2;
                ^", this self::E::named()
     ;
-  constructor named3() → self::E
+  erroneous constructor named3() → self::E
     : final dynamic #t11 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:53:9: Error: A redirecting constructor can't have a 'super' initializer.
       : super(),
         ^^^^^", final dynamic #t12 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:55:16: Error: Can't have initializers after 'super'.
@@ -160,19 +160,19 @@ class E extends core::Object {
         this.y = 2;
                ^", super core::Object::•()
     ;
-  constructor named4() → self::E
+  erroneous constructor named4() → self::E
     : final dynamic #t14 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:58:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 1,
                ^", final dynamic #t15 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:59:16: Error: A redirecting constructor can't have other initializers.
         this.y = 2,
                ^", this self::E::named()
     ;
-  constructor named5() → self::E
+  erroneous constructor named5() → self::E
     : final dynamic #t16 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:62:9: Error: A redirecting constructor can't have other initializers.
       : assert(true),
         ^^^^^^", this self::E::named()
     ;
-  constructor named6() → self::E
+  erroneous constructor named6() → self::E
     : final dynamic #t17 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:66:9: Error: A redirecting constructor can't have other initializers.
         assert(true);
         ^^^^^^", this self::E::named()
@@ -187,7 +187,7 @@ class F extends core::Object {
     : super core::Object::•() {}
 }
 class G extends core::Object {
-  constructor •() → self::G
+  erroneous constructor •() → self::G
     : final dynamic #t19 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:78:9: Error: A redirecting constructor can't have a 'super' initializer.
       : super(),
         ^^^^^", final dynamic #t20 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:80:9: Error: Can't have more than one 'super' initializer.
@@ -197,7 +197,7 @@ class G extends core::Object {
     : super core::Object::•() {}
 }
 class H extends core::Object {
-  constructor •() → self::H
+  erroneous constructor •() → self::H
     : final dynamic #t21 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:87:14: Error: A redirecting constructor can't have more than one redirection.
         this.named();
              ^", this self::H::named()
@@ -213,7 +213,7 @@ class I extends core::Object {
 }
 class J extends core::Object {
   field core::int x;
-  constructor •() → self::J
+  erroneous constructor •() → self::J
     : final dynamic #t23 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:101:16: Error: Can't have initializers after 'super'.
         this.x = 42 {}
                ^", super core::Object::•() {}
diff --git a/pkg/front_end/testcases/general/initialization_errors.dart.strong.modular.expect b/pkg/front_end/testcases/general/initialization_errors.dart.strong.modular.expect
index ea5e456680d..f935cd6dff7 100644
--- a/pkg/front_end/testcases/general/initialization_errors.dart.strong.modular.expect
+++ b/pkg/front_end/testcases/general/initialization_errors.dart.strong.modular.expect
@@ -124,7 +124,7 @@ class C extends core::Object {
 class D extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::D
+  erroneous constructor •() → self::D
     : final dynamic #t5 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:30:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 41,
                ^", final dynamic #t6 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:32:16: Error: A redirecting constructor can't have other initializers.
@@ -136,7 +136,7 @@ class D extends core::Object {
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::E
+  erroneous constructor •() → self::E
     : final dynamic #t7 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:43:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1,
                ^", final dynamic #t8 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:44:16: Error: A redirecting constructor can't have other initializers.
@@ -144,14 +144,14 @@ class E extends core::Object {
                ^", this self::E::named() {}
   constructor named() → self::E
     : self::E::x = 41, self::E::y = 42, super core::Object::•() {}
-  constructor named2() → self::E
+  erroneous constructor named2() → self::E
     : final dynamic #t9 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:49:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 1,
                ^", final dynamic #t10 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:51:16: Error: A redirecting constructor can't have other initializers.
         this.y = 2;
                ^", this self::E::named()
     ;
-  constructor named3() → self::E
+  erroneous constructor named3() → self::E
     : final dynamic #t11 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:53:9: Error: A redirecting constructor can't have a 'super' initializer.
       : super(),
         ^^^^^", final dynamic #t12 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:55:16: Error: Can't have initializers after 'super'.
@@ -160,19 +160,19 @@ class E extends core::Object {
         this.y = 2;
                ^", super core::Object::•()
     ;
-  constructor named4() → self::E
+  erroneous constructor named4() → self::E
     : final dynamic #t14 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:58:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 1,
                ^", final dynamic #t15 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:59:16: Error: A redirecting constructor can't have other initializers.
         this.y = 2,
                ^", this self::E::named()
     ;
-  constructor named5() → self::E
+  erroneous constructor named5() → self::E
     : final dynamic #t16 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:62:9: Error: A redirecting constructor can't have other initializers.
       : assert(true),
         ^^^^^^", this self::E::named()
     ;
-  constructor named6() → self::E
+  erroneous constructor named6() → self::E
     : final dynamic #t17 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:66:9: Error: A redirecting constructor can't have other initializers.
         assert(true);
         ^^^^^^", this self::E::named()
@@ -187,7 +187,7 @@ class F extends core::Object {
     : super core::Object::•() {}
 }
 class G extends core::Object {
-  constructor •() → self::G
+  erroneous constructor •() → self::G
     : final dynamic #t19 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:78:9: Error: A redirecting constructor can't have a 'super' initializer.
       : super(),
         ^^^^^", final dynamic #t20 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:80:9: Error: Can't have more than one 'super' initializer.
@@ -197,7 +197,7 @@ class G extends core::Object {
     : super core::Object::•() {}
 }
 class H extends core::Object {
-  constructor •() → self::H
+  erroneous constructor •() → self::H
     : final dynamic #t21 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:87:14: Error: A redirecting constructor can't have more than one redirection.
         this.named();
              ^", this self::H::named()
@@ -213,7 +213,7 @@ class I extends core::Object {
 }
 class J extends core::Object {
   field core::int x;
-  constructor •() → self::J
+  erroneous constructor •() → self::J
     : final dynamic #t23 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:101:16: Error: Can't have initializers after 'super'.
         this.x = 42 {}
                ^", super core::Object::•() {}
diff --git a/pkg/front_end/testcases/general/initialization_errors.dart.strong.transformed.expect b/pkg/front_end/testcases/general/initialization_errors.dart.strong.transformed.expect
index ea5e456680d..f935cd6dff7 100644
--- a/pkg/front_end/testcases/general/initialization_errors.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/general/initialization_errors.dart.strong.transformed.expect
@@ -124,7 +124,7 @@ class C extends core::Object {
 class D extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::D
+  erroneous constructor •() → self::D
     : final dynamic #t5 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:30:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 41,
                ^", final dynamic #t6 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:32:16: Error: A redirecting constructor can't have other initializers.
@@ -136,7 +136,7 @@ class D extends core::Object {
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::E
+  erroneous constructor •() → self::E
     : final dynamic #t7 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:43:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1,
                ^", final dynamic #t8 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:44:16: Error: A redirecting constructor can't have other initializers.
@@ -144,14 +144,14 @@ class E extends core::Object {
                ^", this self::E::named() {}
   constructor named() → self::E
     : self::E::x = 41, self::E::y = 42, super core::Object::•() {}
-  constructor named2() → self::E
+  erroneous constructor named2() → self::E
     : final dynamic #t9 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:49:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 1,
                ^", final dynamic #t10 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:51:16: Error: A redirecting constructor can't have other initializers.
         this.y = 2;
                ^", this self::E::named()
     ;
-  constructor named3() → self::E
+  erroneous constructor named3() → self::E
     : final dynamic #t11 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:53:9: Error: A redirecting constructor can't have a 'super' initializer.
       : super(),
         ^^^^^", final dynamic #t12 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:55:16: Error: Can't have initializers after 'super'.
@@ -160,19 +160,19 @@ class E extends core::Object {
         this.y = 2;
                ^", super core::Object::•()
     ;
-  constructor named4() → self::E
+  erroneous constructor named4() → self::E
     : final dynamic #t14 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:58:16: Error: A redirecting constructor can't have other initializers.
       : this.x = 1,
                ^", final dynamic #t15 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:59:16: Error: A redirecting constructor can't have other initializers.
         this.y = 2,
                ^", this self::E::named()
     ;
-  constructor named5() → self::E
+  erroneous constructor named5() → self::E
     : final dynamic #t16 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:62:9: Error: A redirecting constructor can't have other initializers.
       : assert(true),
         ^^^^^^", this self::E::named()
     ;
-  constructor named6() → self::E
+  erroneous constructor named6() → self::E
     : final dynamic #t17 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:66:9: Error: A redirecting constructor can't have other initializers.
         assert(true);
         ^^^^^^", this self::E::named()
@@ -187,7 +187,7 @@ class F extends core::Object {
     : super core::Object::•() {}
 }
 class G extends core::Object {
-  constructor •() → self::G
+  erroneous constructor •() → self::G
     : final dynamic #t19 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:78:9: Error: A redirecting constructor can't have a 'super' initializer.
       : super(),
         ^^^^^", final dynamic #t20 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:80:9: Error: Can't have more than one 'super' initializer.
@@ -197,7 +197,7 @@ class G extends core::Object {
     : super core::Object::•() {}
 }
 class H extends core::Object {
-  constructor •() → self::H
+  erroneous constructor •() → self::H
     : final dynamic #t21 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:87:14: Error: A redirecting constructor can't have more than one redirection.
         this.named();
              ^", this self::H::named()
@@ -213,7 +213,7 @@ class I extends core::Object {
 }
 class J extends core::Object {
   field core::int x;
-  constructor •() → self::J
+  erroneous constructor •() → self::J
     : final dynamic #t23 = invalid-expression "pkg/front_end/testcases/general/initialization_errors.dart:101:16: Error: Can't have initializers after 'super'.
         this.x = 42 {}
                ^", super core::Object::•() {}
diff --git a/pkg/front_end/testcases/general/issue43363.dart.strong.expect b/pkg/front_end/testcases/general/issue43363.dart.strong.expect
index 084810f2397..d16ec615e3d 100644
--- a/pkg/front_end/testcases/general/issue43363.dart.strong.expect
+++ b/pkg/front_end/testcases/general/issue43363.dart.strong.expect
@@ -32,7 +32,7 @@ import "dart:core" as core;
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::E
+  erroneous constructor •() → self::E
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1;
                ^", this self::E::named()
diff --git a/pkg/front_end/testcases/general/issue43363.dart.strong.modular.expect b/pkg/front_end/testcases/general/issue43363.dart.strong.modular.expect
index 084810f2397..d16ec615e3d 100644
--- a/pkg/front_end/testcases/general/issue43363.dart.strong.modular.expect
+++ b/pkg/front_end/testcases/general/issue43363.dart.strong.modular.expect
@@ -32,7 +32,7 @@ import "dart:core" as core;
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::E
+  erroneous constructor •() → self::E
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1;
                ^", this self::E::named()
diff --git a/pkg/front_end/testcases/general/issue43363.dart.strong.transformed.expect b/pkg/front_end/testcases/general/issue43363.dart.strong.transformed.expect
index 084810f2397..d16ec615e3d 100644
--- a/pkg/front_end/testcases/general/issue43363.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/general/issue43363.dart.strong.transformed.expect
@@ -32,7 +32,7 @@ import "dart:core" as core;
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
-  constructor •() → self::E
+  erroneous constructor •() → self::E
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1;
                ^", this self::E::named()
diff --git a/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.expect b/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.expect
index 23a00cf0e2d..9d2182af45d 100644
--- a/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.expect
+++ b/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.expect
@@ -26,7 +26,7 @@ class A extends core::Object {
     ;
 }
 class C extends self::A {
-  constructor •(wildcard core::int _#wc0#formal) → self::C
+  erroneous constructor •(wildcard core::int _#wc0#formal) → self::C
     : super self::A::•(_#wc0#formal)
     ;
   constructor r(wildcard core::int _#wc1#formal) → self::C
diff --git a/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.modular.expect b/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.modular.expect
index 23a00cf0e2d..9d2182af45d 100644
--- a/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.modular.expect
+++ b/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.modular.expect
@@ -26,7 +26,7 @@ class A extends core::Object {
     ;
 }
 class C extends self::A {
-  constructor •(wildcard core::int _#wc0#formal) → self::C
+  erroneous constructor •(wildcard core::int _#wc0#formal) → self::C
     : super self::A::•(_#wc0#formal)
     ;
   constructor r(wildcard core::int _#wc1#formal) → self::C
diff --git a/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.outline.expect b/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.outline.expect
index d3ffc75e820..25d2cef5e44 100644
--- a/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.outline.expect
+++ b/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.outline.expect
@@ -20,7 +20,7 @@ class A extends core::Object {
     ;
 }
 class C extends self::A {
-  constructor •(wildcard core::int _#wc0#formal) → self::C
+  erroneous constructor •(wildcard core::int _#wc0#formal) → self::C
     ;
   constructor r(wildcard core::int _#wc1#formal) → self::C
     ;
diff --git a/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.transformed.expect b/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.transformed.expect
index 23a00cf0e2d..9d2182af45d 100644
--- a/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/general/super_initializing_parameters_in_redirecting_generative_constructors.dart.strong.transformed.expect
@@ -26,7 +26,7 @@ class A extends core::Object {
     ;
 }
 class C extends self::A {
-  constructor •(wildcard core::int _#wc0#formal) → self::C
+  erroneous constructor •(wildcard core::int _#wc0#formal) → self::C
     : super self::A::•(_#wc0#formal)
     ;
   constructor r(wildcard core::int _#wc1#formal) → self::C
diff --git a/pkg/front_end/testcases/rasta/super_initializer.dart.strong.expect b/pkg/front_end/testcases/rasta/super_initializer.dart.strong.expect
index 53b86715cce..7666dadd7be 100644
--- a/pkg/front_end/testcases/rasta/super_initializer.dart.strong.expect
+++ b/pkg/front_end/testcases/rasta/super_initializer.dart.strong.expect
@@ -30,17 +30,17 @@ class Super extends core::Object {
 }
 class Sub extends self::Super {
   field dynamic field;
-  constructor arg0() → self::Sub
+  erroneous constructor arg0() → self::Sub
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:15:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg0()
     ;
-  constructor arg1(dynamic a) → self::Sub
+  erroneous constructor arg1(dynamic a) → self::Sub
     : final dynamic #t2 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:18:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg1(a)
     ;
-  constructor arg2(dynamic a, dynamic b) → self::Sub
+  erroneous constructor arg2(dynamic a, dynamic b) → self::Sub
     : final dynamic #t3 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:21:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg2(a, b)
diff --git a/pkg/front_end/testcases/rasta/super_initializer.dart.strong.modular.expect b/pkg/front_end/testcases/rasta/super_initializer.dart.strong.modular.expect
index 53b86715cce..7666dadd7be 100644
--- a/pkg/front_end/testcases/rasta/super_initializer.dart.strong.modular.expect
+++ b/pkg/front_end/testcases/rasta/super_initializer.dart.strong.modular.expect
@@ -30,17 +30,17 @@ class Super extends core::Object {
 }
 class Sub extends self::Super {
   field dynamic field;
-  constructor arg0() → self::Sub
+  erroneous constructor arg0() → self::Sub
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:15:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg0()
     ;
-  constructor arg1(dynamic a) → self::Sub
+  erroneous constructor arg1(dynamic a) → self::Sub
     : final dynamic #t2 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:18:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg1(a)
     ;
-  constructor arg2(dynamic a, dynamic b) → self::Sub
+  erroneous constructor arg2(dynamic a, dynamic b) → self::Sub
     : final dynamic #t3 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:21:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg2(a, b)
diff --git a/pkg/front_end/testcases/rasta/super_initializer.dart.strong.transformed.expect b/pkg/front_end/testcases/rasta/super_initializer.dart.strong.transformed.expect
index 53b86715cce..7666dadd7be 100644
--- a/pkg/front_end/testcases/rasta/super_initializer.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/rasta/super_initializer.dart.strong.transformed.expect
@@ -30,17 +30,17 @@ class Super extends core::Object {
 }
 class Sub extends self::Super {
   field dynamic field;
-  constructor arg0() → self::Sub
+  erroneous constructor arg0() → self::Sub
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:15:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg0()
     ;
-  constructor arg1(dynamic a) → self::Sub
+  erroneous constructor arg1(dynamic a) → self::Sub
     : final dynamic #t2 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:18:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg1(a)
     ;
-  constructor arg2(dynamic a, dynamic b) → self::Sub
+  erroneous constructor arg2(dynamic a, dynamic b) → self::Sub
     : final dynamic #t3 = invalid-expression "pkg/front_end/testcases/rasta/super_initializer.dart:21:15: Error: Can't have initializers after 'super'.
         field = 42;
               ^", super self::Super::arg2(a, b)
diff --git a/pkg/kernel/lib/src/ast/expressions.dart b/pkg/kernel/lib/src/ast/expressions.dart
index 50a20a2fb4d..29bd5d9bee4 100644
--- a/pkg/kernel/lib/src/ast/expressions.dart
+++ b/pkg/kernel/lib/src/ast/expressions.dart
@@ -1405,8 +1405,8 @@ class Arguments extends TreeNode {
             .map((p) => new NamedExpression(p.name!, new VariableGet(p)))
             .toList(),
         types: function.typeParameters
-            .map<DartType>((p) =>
-                new TypeParameterType.withDefaultNullability(p))
+            .map<DartType>(
+                (p) => new TypeParameterType.withDefaultNullability(p))
             .toList());
   }