Fixes for referenced names computing.

pkg/analyzer/lib/src/dart/analysis/referenced_names.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.
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 
 /**
  * Compute the set of external names referenced in the [unit].
  */
@@ skipping 38 matching lines @@
     return scope;
   }
 
   factory _LocalNameScope.forClassTypeAlias(
       _LocalNameScope enclosing, ClassTypeAlias node) {
     _LocalNameScope scope = new _LocalNameScope(enclosing);
     scope.addTypeParameters(node.typeParameters);
     return scope;
   }
 
+  factory _LocalNameScope.forConstructor(
+      _LocalNameScope enclosing, ConstructorDeclaration node) {
+    _LocalNameScope scope = new _LocalNameScope(enclosing);
+    scope.addFormalParameters(node.parameters);
+    return scope;
+  }
+
   factory _LocalNameScope.forFunction(
       _LocalNameScope enclosing, FunctionDeclaration node) {
     _LocalNameScope scope = new _LocalNameScope(enclosing);
     scope.addTypeParameters(node.functionExpression.typeParameters);
     scope.addFormalParameters(node.functionExpression.parameters);
     return scope;
   }
 
   factory _LocalNameScope.forFunctionTypeAlias(
       _LocalNameScope enclosing, FunctionTypeAlias node) {
@@ skipping 99 matching lines @@
     }
   }
 
   @override
   visitCompilationUnit(CompilationUnit node) {
     localScope = new _LocalNameScope.forUnit(node);
     super.visitCompilationUnit(node);
   }
 
   @override
+  visitConstructorDeclaration(ConstructorDeclaration node) {
+    _LocalNameScope outerScope = localScope;
+    try {
+      localScope = new _LocalNameScope.forConstructor(localScope, node);
+      super.visitConstructorDeclaration(node);
+    } finally {
+      localScope = outerScope;
+    }
+  }
+
+  @override
   visitConstructorName(ConstructorName node) {
     if (node.parent is! ConstructorDeclaration) {
       super.visitConstructorName(node);
     }
   }
 
   @override
   visitFunctionDeclaration(FunctionDeclaration node) {
     _LocalNameScope outerScope = localScope;
     try {
@@ skipping 40 matching lines @@
     if (node.inDeclarationContext()) {
       return;
     }
     // Ignore class names references from constructors.
     AstNode parent = node.parent;
     if (parent is ConstructorDeclaration && parent.returnType == node) {
       return;
     }
     // Prepare name.
     String name = node.name;
-    // Ignore unqualified names shadowed by local elements.
-    if (!node.isQualified) {
+    // Ignore names shadowed by local elements.
+    if (node.isQualified || _isNameExpressionLabel(parent)) {
+      // Cannot be local.
+    } else {
       if (localScope.contains(name)) {
         return;
       }
       if (importPrefixNames.contains(name)) {
         return;
       }
     }
     // Do add the name.
     names.add(name);
   }
+
+  static bool _isNameExpressionLabel(AstNode parent) {
+    if (parent is Label) {
+      AstNode parent2 = parent?.parent;
+      return parent2 is NamedExpression && parent2.name == parent;
+    }
+    return false;
+  }
 }