Fix for infinite resursion while finding a concrete method.

pkg/analyzer/lib/src/dart/element/element.dart

 // Copyright (c) 2014, 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 analyzer.src.dart.element.element;
 
 import 'dart:collection';
 import 'dart:math' show min;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 550 matching lines @@
       if (parameter.parameterKind != ParameterKind.REQUIRED) {
         return false;
       }
     }
     return true;
   }
 
   @override
   MethodElement lookUpConcreteMethod(
           String methodName, LibraryElement library) =>
-      _internalLookUpConcreteMethod(methodName, library, true);
+      _internalLookUpConcreteMethod(
+          methodName, library, true, new HashSet<ClassElement>());
 
   @override
   PropertyAccessorElement lookUpGetter(
           String getterName, LibraryElement library) =>
       _internalLookUpGetter(getterName, library, true);
 
   @override
   PropertyAccessorElement lookUpInheritedConcreteGetter(
           String getterName, LibraryElement library) =>
       _internalLookUpConcreteGetter(getterName, library, false);
 
   @override
   MethodElement lookUpInheritedConcreteMethod(
           String methodName, LibraryElement library) =>
-      _internalLookUpConcreteMethod(methodName, library, false);
+      _internalLookUpConcreteMethod(
+          methodName, library, false, new HashSet<ClassElement>());
 
   @override
   PropertyAccessorElement lookUpInheritedConcreteSetter(
           String setterName, LibraryElement library) =>
       _internalLookUpConcreteSetter(setterName, library, false);
 
   @override
   MethodElement lookUpInheritedMethod(
           String methodName, LibraryElement library) =>
-      _internalLookUpMethod(methodName, library, false);
+      _internalLookUpMethod(
+          methodName, library, false, new HashSet<ClassElement>());
 
   @override
   MethodElement lookUpMethod(String methodName, LibraryElement library) =>
-      _internalLookUpMethod(methodName, library, true);
+      _internalLookUpMethod(
+          methodName, library, true, new HashSet<ClassElement>());
 
   @override
   PropertyAccessorElement lookUpSetter(
           String setterName, LibraryElement library) =>
       _internalLookUpSetter(setterName, library, true);
 
   @override
   void visitChildren(ElementVisitor visitor) {
     super.visitChildren(visitor);
     safelyVisitChildren(_accessors, visitor);
@@ skipping 133 matching lines @@
       if (definingClass is! ClassElement) {
         return null;
       }
       getter = getImpl(definingClass)
           ._internalLookUpGetter(getterName, library, false);
     }
     return getter;
   }
 
   MethodElement _internalLookUpConcreteMethod(
-      String methodName, LibraryElement library, bool includeThisClass) {
-    MethodElement method =
-        _internalLookUpMethod(methodName, library, includeThisClass);
+      String methodName,
+      LibraryElement library,
+      bool includeThisClass,
+      HashSet<ClassElement> visitedClasses) {
+    MethodElement method = _internalLookUpMethod(
+        methodName, library, includeThisClass, visitedClasses);
     while (method != null && method.isAbstract) {
       ClassElement definingClass = method.enclosingElement;
       if (definingClass == null) {
         return null;
       }
-      method = definingClass.lookUpInheritedMethod(methodName, library);
+      method = getImpl(definingClass)
+          ._internalLookUpMethod(methodName, library, false, visitedClasses);
     }
     return method;
   }
 
   PropertyAccessorElement _internalLookUpConcreteSetter(
       String setterName, LibraryElement library, bool includeThisClass) {
     PropertyAccessorElement setter =
         _internalLookUpSetter(setterName, library, includeThisClass);
     while (setter != null && setter.isAbstract) {
       Element definingClass = setter.enclosingElement;
@@ skipping 32 matching lines @@
       }
       currentElement = supertype.element;
       PropertyAccessorElement element = currentElement.getGetter(getterName);
       if (element != null && element.isAccessibleIn(library)) {
         return element;
       }
     }
     return null;
   }
 
-  MethodElement _internalLookUpMethod(
-      String methodName, LibraryElement library, bool includeThisClass) {
-    HashSet<ClassElement> visitedClasses = new HashSet<ClassElement>();
+  MethodElement _internalLookUpMethod(String methodName, LibraryElement library,
+      bool includeThisClass, HashSet<ClassElement> visitedClasses) {
     ClassElement currentElement = this;
     if (includeThisClass) {
       MethodElement element = currentElement.getMethod(methodName);
       if (element != null && element.isAccessibleIn(library)) {
         return element;
       }
     }
     while (currentElement != null && visitedClasses.add(currentElement)) {
       for (InterfaceType mixin in currentElement.mixins.reversed) {
         ClassElement mixinElement = mixin.element;
@@ skipping 4130 matching lines @@
 
   @override
   void visitElement(Element element) {
     int offset = element.nameOffset;
     if (offset != -1) {
       map[offset] = element;
     }
     super.visitElement(element);
   }
 }