[cfe] Use the supertype locations when reporting errors

Closes #45626.

Bug: #45626
Change-Id: I672efb0bba516534151630e6627959e0971840e5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/195515
Commit-Queue: Dmitry Stefantsov <dmitryas@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Erik Ernst <eernst@google.com>

pkg/front_end/lib/src/fasta/builder/class_builder.dart

@@ -705,7 +705,7 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
     Set<ClassBuilder> implemented = new Set<ClassBuilder>();
     for (TypeBuilder type in interfaceBuilders) {
       if (type is NamedTypeBuilder) {
-        int charOffset = -1; // TODO(ahe): Get offset from type.
+        int charOffset = type.charOffset;
         TypeDeclarationBuilder typeDeclaration = type.declaration;
         TypeDeclarationBuilder decl;
         TypeAliasBuilder aliasBuilder; // Non-null if a type alias is used.

pkg/front_end/test/spell_checking_list_tests.txt

@@ -135,6 +135,7 @@ class5b
 class5c
 class5d
 cloneable
+cm
 cmd
 cmp
 cnn

pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart

@@ -0,0 +1,22 @@
+// Copyright (c) 2021, 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.
+
+import 'issue45626.dart' as self;
+
+class C {}
+typedef CAlias = C;
+
+class D implements C, C {}
+class D2 implements C, CAlias {}
+class D3 implements CAlias, C {}
+class D4 implements C, self.C {}
+class D5 implements self.C, C {}
+
+mixin CM on C, C {}
+mixin CM2 on C, CAlias {}
+mixin CM3 on CAlias, C {}
+mixin CM4 on self.C, C {}
+mixin CM5 on C, self.C {}
+
+main() {}

pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart.strong.expect

@@ -0,0 +1,126 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:10:23: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D implements C, C {}
+//                       ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:11:24: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D2 implements C, CAlias {}
+//                        ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:12:29: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D3 implements CAlias, C {}
+//                             ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:13:24: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D4 implements C, self.C {}
+//                        ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:14:29: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D5 implements self.C, C {}
+//                             ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:16:16: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM on C, C {}
+//                ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:17:17: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM2 on C, CAlias {}
+//                 ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:18:22: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM3 on CAlias, C {}
+//                      ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:19:22: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM4 on self.C, C {}
+//                      ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:20:17: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM5 on C, self.C {}
+//                 ^
+//
+import self as self;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///issue45626.dart" as self;
+
+typedef CAlias = self::C;
+class C extends core::Object {
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+}
+class D extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D
+    : super core::Object::•()
+    ;
+}
+class D2 extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+}
+class D3 extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+class D4 extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+class D5 extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D5
+    : super core::Object::•()
+    ;
+}
+abstract class _CM&C&C extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM&C&C
+    : super core::Object::•()
+    ;
+}
+abstract class CM extends self::_CM&C&C /*isMixinDeclaration*/  {
+}
+abstract class _CM2&C&CAlias extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM2&C&CAlias
+    : super core::Object::•()
+    ;
+}
+abstract class CM2 extends self::_CM2&C&CAlias /*isMixinDeclaration*/  {
+}
+abstract class _CM3&CAlias&C extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM3&CAlias&C
+    : super core::Object::•()
+    ;
+}
+abstract class CM3 extends self::_CM3&CAlias&C /*isMixinDeclaration*/  {
+}
+abstract class _CM4&C&C extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM4&C&C
+    : super core::Object::•()
+    ;
+}
+abstract class CM4 extends self::_CM4&C&C /*isMixinDeclaration*/  {
+}
+abstract class _CM5&C&C extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM5&C&C
+    : super core::Object::•()
+    ;
+}
+abstract class CM5 extends self::_CM5&C&C /*isMixinDeclaration*/  {
+}
+static method main() → dynamic {}

pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart.strong.transformed.expect

@@ -0,0 +1,126 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:10:23: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D implements C, C {}
+//                       ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:11:24: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D2 implements C, CAlias {}
+//                        ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:12:29: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D3 implements CAlias, C {}
+//                             ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:13:24: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D4 implements C, self.C {}
+//                        ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:14:29: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// class D5 implements self.C, C {}
+//                             ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:16:16: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM on C, C {}
+//                ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:17:17: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM2 on C, CAlias {}
+//                 ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:18:22: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM3 on CAlias, C {}
+//                      ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:19:22: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM4 on self.C, C {}
+//                      ^
+//
+// pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart:20:17: Error: 'C' can only be implemented once.
+// Try removing 1 of the occurrences.
+// mixin CM5 on C, self.C {}
+//                 ^
+//
+import self as self;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///issue45626.dart" as self;
+
+typedef CAlias = self::C;
+class C extends core::Object {
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+}
+class D extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D
+    : super core::Object::•()
+    ;
+}
+class D2 extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+}
+class D3 extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+class D4 extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+class D5 extends core::Object implements self::C, self::C {
+  synthetic constructor •() → self::D5
+    : super core::Object::•()
+    ;
+}
+abstract class _CM&C&C extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM&C&C
+    : super core::Object::•()
+    ;
+}
+abstract class CM extends self::_CM&C&C /*isMixinDeclaration*/  {
+}
+abstract class _CM2&C&CAlias extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM2&C&CAlias
+    : super core::Object::•()
+    ;
+}
+abstract class CM2 extends self::_CM2&C&CAlias /*isMixinDeclaration*/  {
+}
+abstract class _CM3&CAlias&C extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM3&CAlias&C
+    : super core::Object::•()
+    ;
+}
+abstract class CM3 extends self::_CM3&CAlias&C /*isMixinDeclaration*/  {
+}
+abstract class _CM4&C&C extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM4&C&C
+    : super core::Object::•()
+    ;
+}
+abstract class CM4 extends self::_CM4&C&C /*isMixinDeclaration*/  {
+}
+abstract class _CM5&C&C extends core::Object implements self::C, self::C /*isAnonymousMixin*/  {
+  synthetic constructor •() → self::_CM5&C&C
+    : super core::Object::•()
+    ;
+}
+abstract class CM5 extends self::_CM5&C&C /*isMixinDeclaration*/  {
+}
+static method main() → dynamic {}

pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart.textual_outline.expect

@@ -0,0 +1,22 @@
+import 'issue45626.dart' as self;
+
+class C {}
+
+typedef CAlias = C;
+
+class D implements C, C {}
+
+class D2 implements C, CAlias {}
+
+class D3 implements CAlias, C {}
+
+class D4 implements C, self.C {}
+
+class D5 implements self.C, C {}
+
+mixin CM on C, C {}
+mixin CM2 on C, CAlias {}
+mixin CM3 on CAlias, C {}
+mixin CM4 on self.C, C {}
+mixin CM5 on C, self.C {}
+main() {}

pkg/front_end/testcases/nonfunction_type_aliases/issue45626.dart.textual_outline_modelled.expect

@@ -0,0 +1,21 @@
+import 'issue45626.dart' as self;
+
+class C {}
+
+class D implements C, C {}
+
+class D2 implements C, CAlias {}
+
+class D3 implements CAlias, C {}
+
+class D4 implements C, self.C {}
+
+class D5 implements self.C, C {}
+
+main() {}
+mixin CM on C, C {}
+mixin CM2 on C, CAlias {}
+mixin CM3 on CAlias, C {}
+mixin CM4 on self.C, C {}
+mixin CM5 on C, self.C {}
+typedef CAlias = C;