Check for cyclicity in named mixin applications.

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 3495 matching lines @@
     : context = Scope.buildEnclosingScope(cls),
       this.classElement = cls,
       super(compiler);
 
   void loadSupertype(ClassElement element, Node from) {
     compiler.resolver.loadSupertypes(element, from);
     element.ensureResolved(compiler);
   }
 
   void visitNodeList(NodeList node) {
-    for (Link<Node> link = node.nodes; !link.isEmpty; link = link.tail) {
-      link.head.accept(this);
+    if (node != null) {
+      for (Link<Node> link = node.nodes; !link.isEmpty; link = link.tail) {
+        link.head.accept(this);
+      }
     }
   }
 
   void visitClassNode(ClassNode node) {
     if (node.superclass == null) {
       if (!identical(classElement, compiler.objectClass)) {
         loadSupertype(compiler.objectClass, node);
       }
     } else {
       node.superclass.accept(this);
     }
     visitNodeList(node.interfaces);
   }
 
   void visitMixinApplication(MixinApplication node) {
     node.superclass.accept(this);
     visitNodeList(node.mixins);
   }
 
+  void visitNamedMixinApplication(NamedMixinApplication node) {
+    node.superclass.accept(this);
+    visitNodeList(node.mixins);
+    visitNodeList(node.interfaces);
+  }
+
   void visitTypeAnnotation(TypeAnnotation node) {
     node.typeName.accept(this);
   }
 
   void visitIdentifier(Identifier node) {
     Element element = context.lookup(node.source);
     if (element == null) {
       error(node, MessageKind.CANNOT_RESOLVE_TYPE, {'typeName': node});
     } else if (!element.impliesType()) {
       error(node, MessageKind.NOT_A_TYPE, {'node': node});
@@ skipping 439 matching lines @@
     return e;
   }
 
   /// Assumed to be called by [resolveRedirectingFactory].
   Element visitReturn(Return node) {
     Node expression = node.expression;
     return finishConstructorReference(visit(expression),
                                       expression, expression);
   }
 }