Fix crash in typechecker

pkg/compiler/lib/src/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.
 
 part of dart2js;
 
 class TypeCheckerTask extends CompilerTask {
   TypeCheckerTask(Compiler compiler) : super(compiler);
   String get name => "Type checker";
 
@@ skipping 1086 matching lines @@
         receiverType = superType;
       } else {
         assert(node.selector.isThis());
         receiverType = thisType;
       }
       DartType constructorType = computeConstructorType(element, receiverType);
       analyzeArguments(node, element, constructorType);
       return const DynamicType();
     }
 
+    Identifier selector = node.selector.asIdentifier();
     if (Elements.isClosureSend(node, element)) {
       if (element != null) {
         // foo() where foo is a local or a parameter.
         return analyzeInvocation(node, createPromotedAccess(element));
       } else {
         // exp() where exp is some complex expression like (o) or foo().
         DartType type = analyze(node.selector);
         return analyzeInvocation(node, new TypeAccess(type));
       }
+    } else if (Elements.isErroneousElement(element) && selector == null) {
+      // exp() where exp is an erroneous construct like `new Unresolved()`.
+      DartType type = analyze(node.selector);
+      return analyzeInvocation(node, new TypeAccess(type));
     }
 
-    Identifier selector = node.selector.asIdentifier();
     String name = selector.source;
 
     if (node.isOperator && identical(name, 'is')) {
       analyze(node.receiver);
       if (!node.isIsNotCheck) {
         Element variable = elements[node.receiver];
         if (variable == null) {
           // Look for the variable element within parenthesized expressions.
           ParenthesizedExpression parentheses =
               node.receiver.asParenthesizedExpression();
@@ skipping 691 matching lines @@
 
   visitTypedef(Typedef node) {
     // Do not typecheck [Typedef] nodes.
   }
 
   visitNode(Node node) {
     compiler.internalError(node,
         'Unexpected node ${node.getObjectDescription()} in the type checker.');
   }
 }