Update check for cyclic typedefs.

sdk/lib/_internal/compiler/implementation/resolution/members.dart

 // Copyright (c) 2012, 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.
 
 part of resolution;
 
 abstract class TreeElements {
   Element get currentElement;
   Set<Node> get superUses;
 
@@ skipping 3572 matching lines @@
     element.functionSignature = signature;
 
     scope = new MethodScope(scope, element);
     signature.forEachParameter((Element element) {
       defineElement(element.parseNode(compiler), element);
     });
 
     element.alias = compiler.computeFunctionType(element, signature);
 
     void checkCyclicReference() {
-      var visitor = new TypedefCyclicVisitor(compiler, element);
-      type.accept(visitor, null);
+      element.checkCyclicReference(compiler);
     }
     addPostProcessAction(element, checkCyclicReference);
   }
 }
 
 // TODO(johnniwinther): Replace with a traversal on the AST when the type
 // annotations in typedef alias are stored in a [TreeElements] mapping.
 class TypedefCyclicVisitor extends DartTypeVisitor {
   final Compiler compiler;
-  final TypedefElement element;
+  final TypedefElementX element;
   bool hasCyclicReference = false;
 
-  /// Counter for how many bounds the visitor currently has on the call-stack.
-  /// Used to detect when to report [Messagekind.CYCLIC_TYPEDEF_TYPEVAR].
-  int seenBoundsCount = 0;
-
   Link<TypedefElement> seenTypedefs = const Link<TypedefElement>();
 
   int seenTypedefsCount = 0;
 
   Link<TypeVariableElement> seenTypeVariables =
       const Link<TypeVariableElement>();
 
   TypedefCyclicVisitor(Compiler this.compiler, TypedefElement this.element);
 
   visitType(DartType type, _) {
     // Do nothing.
   }
 
   visitTypedefType(TypedefType type, _) {
     TypedefElement typedefElement = type.element;
     if (seenTypedefs.contains(typedefElement)) {
       if (!hasCyclicReference && identical(element, typedefElement)) {
         // Only report an error on the checked typedef to avoid generating
         // multiple errors for the same cyclicity.
         hasCyclicReference = true;
-        if (seenBoundsCount > 0) {
-          compiler.reportError(element, MessageKind.CYCLIC_TYPEDEF_TYPEVAR);
-        } else if (seenTypedefsCount == 1) {
+        if (seenTypedefsCount == 1) {
           // Direct cyclicity.
           compiler.reportError(element,
               MessageKind.CYCLIC_TYPEDEF,
               {'typedefName': element.name});
         } else if (seenTypedefsCount == 2) {
           // Cyclicity through one other typedef.
           compiler.reportError(element,
               MessageKind.CYCLIC_TYPEDEF_ONE,
               {'typedefName': element.name,
                'otherTypedefName': seenTypedefs.head.name});
         } else {
           // Cyclicity through more than one other typedef.
           for (TypedefElement cycle in seenTypedefs) {
             if (!identical(typedefElement, cycle)) {
               compiler.reportError(element,
                   MessageKind.CYCLIC_TYPEDEF_ONE,
                   {'typedefName': element.name,
                    'otherTypedefName': cycle.name});
             }
           }
         }
+        ErroneousElementX erroneousElement = new ErroneousElementX(
+              MessageKind.CYCLIC_TYPEDEF,
+              {'typedefName': element.name},
+              element.name, element);
+        element.alias =
+            new MalformedType(erroneousElement, typedefElement.alias);
+        element.hasBeenCheckedForCycles = true;
       }
     } else {
       seenTypedefs = seenTypedefs.prepend(typedefElement);
       seenTypedefsCount++;
       type.visitChildren(this, null);
       typedefElement.alias.accept(this, null);
       seenTypedefs = seenTypedefs.tail;
       seenTypedefsCount--;
     }
   }
 
   visitFunctionType(FunctionType type, _) {
     type.visitChildren(this, null);
   }
 
   visitInterfaceType(InterfaceType type, _) {
     type.visitChildren(this, null);
   }
 
   visitTypeVariableType(TypeVariableType type, _) {
     TypeVariableElement typeVariableElement = type.element;
     if (seenTypeVariables.contains(typeVariableElement)) {
       // Avoid running in cycles on cyclic type variable bounds.
       // Cyclicity is reported elsewhere.
       return;
     }
     seenTypeVariables = seenTypeVariables.prepend(typeVariableElement);
-    seenBoundsCount++;
     typeVariableElement.bound.accept(this, null);
-    seenBoundsCount--;
     seenTypeVariables = seenTypeVariables.tail;
   }
 }
 
 /**
  * The implementation of [ResolverTask.resolveClass].
  *
  * This visitor has to be extra careful as it is building the basic
  * element information, and cannot safely look at other elements as
  * this may lead to cycles.
@@ skipping 947 matching lines @@
     return finishConstructorReference(visit(expression),
                                       expression, expression);
   }
 }
 
 /// Looks up [name] in [scope] and unwraps the result.
 Element lookupInScope(Compiler compiler, Node node,
                       Scope scope, SourceString name) {
   return Elements.unwrap(scope.lookup(name), compiler, node);
 }