Check for cyclic reference in typedefs

sdk/lib/_internal/compiler/implementation/dart_types.dart

Index: sdk/lib/_internal/compiler/implementation/dart_types.dart
diff --git a/sdk/lib/_internal/compiler/implementation/dart_types.dart b/sdk/lib/_internal/compiler/implementation/dart_types.dart
index 5f00a6239398959059aec7c69a12f529a4a0d9a7..fe390de8ec432ba87c93e099fb322483d179e2ee 100644
--- a/sdk/lib/_internal/compiler/implementation/dart_types.dart
+++ b/sdk/lib/_internal/compiler/implementation/dart_types.dart
@@ -894,6 +894,27 @@ abstract class DartTypeVisitor<R, A> {
       visitInterfaceType(type, argument);
 }
 
+abstract class DartTypeTraversal extends DartTypeVisitor {

[ahe, 2013/04/02 08:22:39]

As I understand it, there is one subclass of this class.  That subclass is
temporary.  So one could get the feeling that this class doesn't pull its own
weight.

Also, did you consider the visitChildren approach from AST nodes?

[Johnni Winther, 2013/04/02 09:40:14]

Changed to use the visitChildren approach.

+  visit(DartType type) => type.accept(this, null);
+
+  visitList(Link<DartType> types) {
+    for (Link<DartType> link = types; !link.isEmpty; link = link.tail) {
+      visit(link.head);
+    }
+  }
+
+  visitFunctionType(FunctionType type, _) {
+    visit(type.returnType);
+    visitList(type.parameterTypes);
+    visitList(type.optionalParameterTypes);
+    visitList(type.namedParameterTypes);
+  }
+
+  visitGenericType(GenericType type, _) {
+    visitList(type.typeArguments);
+  }
+}
+
 class SubtypeVisitor extends DartTypeVisitor<bool, DartType> {
   final Compiler compiler;
   final DynamicType dynamicType;