Bring type variables into static scope, but produce compile-time error when they are used.

lib/compiler/implementation/typechecker.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.
 
 class TypeCheckerTask extends CompilerTask {
   TypeCheckerTask(Compiler compiler) : super(compiler);
   String get name => "Type checker";
 
   static const bool LOG_FAILURES = false;
 
@@ skipping 100 matching lines @@
 
   DartType unalias(Compiler compiler) => this;
 
   int hashCode() => 1729;
 
   bool operator ==(other) => other is VoidType;
 
   String toString() => name.slowToString();
 }
 
+class MalformedType implements DartType {
+  const MalformedType(this.element);
+  SourceString get name => element.name;
+  final MalformedTypeElement element;
+
+  DartType unalias(Compiler compiler) => this;
+
+  int hashCode() => 1733;
+
+  bool operator ==(other) => other is MalformedType;
+
+  String toString() => name.slowToString();
+}
+
 class InterfaceType implements DartType {
   final Element element;
   final Link<DartType> arguments;
 
   const InterfaceType(this.element,
                       [this.arguments = const EmptyLink<DartType>()]);
 
   SourceString get name => element.name;
 
   DartType unalias(Compiler compiler) => this;
@@ skipping 138 matching lines @@
         s === dynamicType ||
         s.element === compiler.objectClass ||
         t.element === compiler.nullClass) {
       return true;
     }
     t = t.unalias(compiler);
     s = s.unalias(compiler);
 
     if (t is VoidType) {
       return false;
+    } else if (t is MalformedType) {
+      return false;
     } else if (t is InterfaceType) {
       if (s is !InterfaceType) return false;
       ClassElement tc = t.element;
       if (tc === s.element) return true;
       for (Link<DartType> supertypes = tc.allSupertypes;
            supertypes != null && !supertypes.isEmpty();
            supertypes = supertypes.tail) {
         DartType supertype = supertypes.head;
         if (supertype.element === s.element) return true;
       }
@@ skipping 689 matching lines @@
   }
 
   DartType visitStatement(Statement node) {
     compiler.unimplemented('visitNode', node: node);
   }
 
   DartType visitStringNode(StringNode node) {
     compiler.unimplemented('visitNode', node: node);
   }
 }