Implement fullNameForErrors on all Builders.

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

 // Copyright (c) 2016, 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.
 
 library fasta.scope;
 
 import 'builder.dart' show Builder, MixedAccessor;
 
 import '../errors.dart' show internalError;
 
@@ skipping 19 matching lines @@
     return new Scope(<String, Builder>{}, this, isModifiable: isModifiable);
   }
 
   Builder lookup(String name, int charOffset, Uri fileUri) {
     Builder builder = local[name];
     if (builder != null) {
       if (builder.next != null) {
         return lookupAmbiguous(name, builder, false, charOffset, fileUri);
       }
       return builder.isSetter
-          ? new AccessErrorBuilder(builder, charOffset, fileUri)
+          ? new AccessErrorBuilder(name, builder, charOffset, fileUri)
           : builder;
     } else {
       return parent?.lookup(name, charOffset, fileUri);
     }
   }
 
   Builder lookupSetter(String name, int charOffset, Uri fileUri) {
     Builder builder = local[name];
     if (builder != null) {
       if (builder.next != null) {
         return lookupAmbiguous(name, builder, true, charOffset, fileUri);
       }
       if (builder.isField) {
         if (builder.isFinal) {
-          return new AccessErrorBuilder(builder, charOffset, fileUri);
+          return new AccessErrorBuilder(name, builder, charOffset, fileUri);
         } else {
           return builder;
         }
       } else if (builder.isSetter) {
         return builder;
       } else {
-        return new AccessErrorBuilder(builder, charOffset, fileUri);
+        return new AccessErrorBuilder(name, builder, charOffset, fileUri);
       }
     } else {
       return parent?.lookupSetter(name, charOffset, fileUri);
     }
   }
 
   Builder lookupAmbiguous(
       String name, Builder builder, bool setter, int charOffset, Uri fileUri) {
     assert(builder.next != null);
     if (builder is MixedAccessor) {
       return setter ? builder.setter : builder.getter;
     }
     Builder setterBuilder;
     Builder getterBuilder;
     Builder current = builder;
     while (current != null) {
       if (current.isGetter && getterBuilder == null) {
         getterBuilder = current;
       } else if (current.isSetter && setterBuilder == null) {
         setterBuilder = current;
       } else {
-        return new AmbiguousBuilder(builder, charOffset, fileUri);
+        return new AmbiguousBuilder(name, builder, charOffset, fileUri);
       }
       current = current.next;
     }
     assert(getterBuilder != null);
     assert(setterBuilder != null);
     return setter ? setterBuilder : getterBuilder;
   }
 
   bool hasLocalLabel(String name) => labels != null && labels.containsKey(name);
 
@@ skipping 31 matching lines @@
   // TODO(ahe): Rename to extend or something.
   void operator []=(String name, Builder member) {
     if (isModifiable) {
       local[name] = member;
     } else {
       internalError("Can't extend an unmodifiable scope.");
     }
   }
 }
 
-class AccessErrorBuilder extends Builder {
+abstract class ProblemBuilder extends Builder {
+  final String name;
+
   final Builder builder;
 
-  AccessErrorBuilder(this.builder, int charOffset, Uri fileUri)
+  ProblemBuilder(this.name, this.builder, int charOffset, Uri fileUri)
       : super(null, charOffset, fileUri);
 
+  get target => null;
+
+  bool get hasProblem => true;
+
+  String get message;
+
+  @override
+  String get fullNameForErrors => name;
+}
+
+/// Represents a [builder] that's being accessed incorrectly. For example, an
+/// attempt to write to a final field, or to read from a setter.
+class AccessErrorBuilder extends ProblemBuilder {
+  AccessErrorBuilder(String name, Builder builder, int charOffset, Uri fileUri)
+      : super(name, builder, charOffset, fileUri);
+
   Builder get parent => builder;
 
-  get target => null;
-
   bool get isFinal => builder.isFinal;
 
   bool get isField => builder.isField;
 
   bool get isRegularMethod => builder.isRegularMethod;
 
   bool get isGetter => !builder.isGetter;
 
   bool get isSetter => !builder.isSetter;
 
   bool get isInstanceMember => builder.isInstanceMember;
 
   bool get isStatic => builder.isStatic;
 
   bool get isTopLevel => builder.isTopLevel;
 
   bool get isTypeDeclaration => builder.isTypeDeclaration;
 
   bool get isLocal => builder.isLocal;
 
-  bool get hasProblem => true;
+  String get message => "Access error: '$name'.";
 }
 
-class AmbiguousBuilder extends Builder {
-  final Builder builder;
+class AmbiguousBuilder extends ProblemBuilder {
+  AmbiguousBuilder(String name, Builder builder, int charOffset, Uri fileUri)
+      : super(name, builder, charOffset, fileUri);
 
-  AmbiguousBuilder(this.builder, int charOffset, Uri fileUri)
-      : super(null, charOffset, fileUri);
-
-  get target => null;
-
-  bool get hasProblem => true;
+  String get message => "Duplicated named: '$name'.";
 }