Resolve typedefs.

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 final bool LOG_FAILURES = false;
 
@@ skipping 214 matching lines @@
       typeArguments.printOn(sb, ', ');
       sb.add('>');
     }
     return sb.toString();
   }
 }
 
 class FunctionType implements Type {
   final Element element;
   final Type returnType;
-  final Link<Type> parameterTypes;
+  Link<Type> parameterTypes;
 
-  const FunctionType(Type this.returnType, Link<Type> this.parameterTypes,
-                     Element this.element);
+  FunctionType(Type this.returnType, Link<Type> this.parameterTypes,
+               Element this.element);
 
   Type subst(Compiler compiler, Link<Type> arguments,
              LinkedHashMap<SourceString, TypeVariableElement> typeParameters) {
     if (typeParameters.isEmpty()) {
       // Return fast on empty substitutions.
       return this;
     }
     var newReturnType = returnType.subst(compiler, arguments, typeParameters);
     bool changed = newReturnType !== returnType;
     var newParameterTypesBuilder = new LinkBuilder<Type>();
@@ skipping 824 matching lines @@
   }
 
   visitCatchBlock(CatchBlock node) {
     return unhandledStatement();
   }
 
   visitTypedef(Typedef node) {
     return unhandledStatement();
   }
 }