Don't call dinvoke on Object methods

lib/src/checker/checker.dart

 // Copyright (c) 2015, 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 dev_compiler.src.checker.checker;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/scanner.dart' show Token, TokenType;
@@ skipping 559 matching lines @@
     node.expression = _checkReturn(node.expression, node);
     node.visitChildren(this);
   }
 
   visitReturnStatement(ReturnStatement node) {
     node.expression = _checkReturn(node.expression, node);
     node.visitChildren(this);
   }
 
   visitPropertyAccess(PropertyAccess node) {
-    if (_rules.isDynamicGet(node.realTarget)) {
+    if (node.staticType.isDynamic && _rules.isDynamicTarget(node.realTarget)) {
       _recordDynamicInvoke(node);
     }
     node.visitChildren(this);
   }
 
   visitPrefixedIdentifier(PrefixedIdentifier node) {
     final target = node.prefix;
-    // Check if the prefix is a library - PrefixElement denotes a library
-    // access.
-    if (target.staticElement is! PrefixElement && _rules.isDynamicGet(target)) {
+    if (_rules.isDynamicTarget(target)) {
       _recordDynamicInvoke(node);
     }
     node.visitChildren(this);
   }
 
   @override visitDefaultFormalParameter(DefaultFormalParameter node) {
     _visitMaybeConst(node, (node) {
       // Check that defaults have the proper subtype.
       var parameter = node.parameter;
       var parameterType = _rules.elementType(parameter.element);
@@ skipping 202 matching lines @@
   void _recordDynamicInvoke(AstNode node) {
     _reporter.log(new DynamicInvoke(_rules, node));
   }
 
   void _recordMessage(StaticInfo info) {
     if (info == null) return;
     if (info.level >= logger.Level.SEVERE) _failure = true;
     _reporter.log(info);
   }
 }