Handle clash of prefix/non-prefix imports.

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 4457 matching lines @@
     Identifier name = node.selector.asIdentifier();
     if (name == null) internalError(node.selector, 'unexpected node');
 
     if (identical(e.kind, ElementKind.CLASS)) {
       ClassElement cls = e;
       cls.ensureResolved(compiler);
       return lookupConstructor(cls, name, name.source);
     } else if (identical(e.kind, ElementKind.PREFIX)) {
       PrefixElement prefix = e;
       e = prefix.lookupLocalMember(name.source);
+      e = Elements.unwrap(e, compiler, node);
       if (e == null) {
         return failOrReturnErroneousElement(
             resolver.enclosingElement, name,
             name.source,
             MessageKind.CANNOT_RESOLVE,
             {'name': name});
       } else if (!identical(e.kind, ElementKind.CLASS)) {
         error(node, MessageKind.NOT_A_TYPE.error, {'node': name});
       }
     } else {
@@ skipping 32 matching lines @@
     return finishConstructorReference(visit(expression),
                                       expression, expression);
   }
 }
 
 /// Looks up [name] in [scope] and unwraps the result.
 Element lookupInScope(Compiler compiler, Node node,
                       Scope scope, SourceString name) {
   return Elements.unwrap(scope.lookup(name), compiler, node);
 }