Report errors and warnings for hiding elements, issue 572.

compiler/java/com/google/dart/compiler/resolver/ResolutionContext.java

 // Copyright (c) 2011, 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.
 
 package com.google.dart.compiler.resolver;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.dart.compiler.DartCompilationError;
 import com.google.dart.compiler.DartCompilerContext;
 import com.google.dart.compiler.ErrorCode;
@@ skipping 48 matching lines @@
   }
 
   ResolutionContext extend(String name) {
     return new ResolutionContext(new Scope(name, scope.getLibrary(), scope), context, typeProvider);
   }
 
   Scope getScope() {
     return scope;
   }
 
-  void declare(Element element) {
-    Element existingElement = scope.declareElement(element.getName(), element);
-    if (existingElement != null) {
-      onError(element.getNode(), ResolverErrorCode.DUPLICATE_TOP_LEVEL_DEFINITION,
-          element.getName());
+  void declare(Element element, ErrorCode errorCode, ErrorCode warningCode) {
+    String name = element.getName();
+    Element existingLocalElement = scope.findLocalElement(name);
+    // Check for duplicate declaration in the enclosing scope.
+    if (existingLocalElement == null && warningCode != null) {
+      Element existingElement = scope.findElement(scope.getLibrary(), name);
+      if (existingElement != null) {
+        if (!Elements.isConstructorParameter(element)
+            && !Elements.isParameterOfMethodWithoutBody(element)
+            && !(Elements.isStaticContext(element) && !Elements.isStaticContext(existingElement))
+            && !existingElement.getModifiers().isAbstractField()) {
+          DartNode nameNode = Elements.getNameNode(element);
+          String existingLocation = Elements.getRelativeElementLocation(element, existingElement);
+          onError(nameNode, warningCode, name, existingElement, existingLocation);
+        }
+      }
     }
+    // Check for duplicate declaration in the same scope.
+    if (existingLocalElement != null && errorCode != null) {
+      DartNode nameNode = Elements.getNameNode(element);
+      String existingLocation = Elements.getRelativeElementLocation(element, existingLocalElement);
+      onError(nameNode, errorCode, name, existingLocation);
+    }
+    // Declare, may be hide existing element.
+    scope.declareElement(name, element);
   }
 
   void pushScope(String name) {
     scope = new Scope(name, scope.getLibrary(), scope);
   }
 
   void popScope() {
     scope = scope.getParent();
   }
 
@@ skipping 153 matching lines @@
     return element.getTypeVariable();
   }
 
   Element resolveName(DartNode node) {
     return node.accept(new Selector());
   }
 
   MethodElement declareFunction(DartFunctionExpression node) {
     MethodElement element = Elements.methodFromFunctionExpression(node, Modifiers.NONE);
     if (node.getFunctionName() != null) {
-      declare(element);
+      declare(
+          element,
+          ResolverErrorCode.DUPLICATE_FUNCTION_EXPRESSION,
+          ResolverErrorCode.DUPLICATE_FUNCTION_EXPRESSION_WARNING);
     }
     return element;
   }
 
   void pushFunctionScope(DartFunctionExpression x) {
     pushScope(x.getFunctionName() == null ? "<function>" : x.getFunctionName());
   }
 
   void pushFunctionAliasScope(DartFunctionTypeAlias x) {
     pushScope(x.getName().getTargetName() == null ? "<function>" : x.getName().getTargetName());
@@ skipping 36 matching lines @@
       return null;
     }
 
     @Override
     public Element visitIdentifier(DartIdentifier node) {
       String name = node.getTargetName();
       return scope.findElement(scope.getLibrary(), name);
     }
   }
 }