Differentiate between unresolved class and constructor.

pkg/compiler/lib/src/resolution/send_resolver.dart

 // Copyright (c) 2015, 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.semantics_visitor;
 
 enum SendStructureKind {
   GET,
   SET,
   INVOKE,
@@ skipping 401 matching lines @@
       } else {
         return handleStaticallyResolvedAccess(node, element, getter);
       }
     }
   }
 
   ConstructorAccessSemantics computeConstructorAccessSemantics(
         ConstructorElement constructor,
         DartType type) {
     if (constructor.isErroneous) {
+      if (constructor is ErroneousElement) {
+        ErroneousElement error = constructor;
+        if (error.messageKind == MessageKind.CANNOT_FIND_CONSTRUCTOR) {
+          return new ConstructorAccessSemantics(
+              ConstructorAccessKind.UNRESOLVED_CONSTRUCTOR, constructor, type);
+        }
+      }
       return new ConstructorAccessSemantics(
-          ConstructorAccessKind.ERRONEOUS, constructor, type);
+          ConstructorAccessKind.UNRESOLVED_TYPE, constructor, type);
     } else if (constructor.isRedirectingFactory) {
       ConstructorElement effectiveTarget = constructor.effectiveTarget;
       if (effectiveTarget == constructor ||
           effectiveTarget.isErroneous) {
         return new ConstructorAccessSemantics(
             ConstructorAccessKind.ERRONEOUS_REDIRECTING_FACTORY,
             constructor,
             type);
       }
       ConstructorAccessSemantics effectiveTargetSemantics =
@@ skipping 41 matching lines @@
 
     Element element = elements[node.send];
     Selector selector = elements.getSelector(node.send);
     DartType type = elements.getType(node);
 
     ConstructorAccessSemantics constructorAccessSemantics;
     if (node.isConst) {
       // This is a non-constant constant constructor invocation, like
       // `const Const(method())`.
       constructorAccessSemantics = new ConstructorAccessSemantics(
-          ConstructorAccessKind.ERRONEOUS, element, type);
+          ConstructorAccessKind.NON_CONSTANT_CONSTRUCTOR, element, type);
     } else {
       constructorAccessSemantics =
           computeConstructorAccessSemantics(element, type);
     }
     return new NewInvokeStructure(constructorAccessSemantics, selector);
   }
 }
 
 abstract class DeclStructure<R, A> {
   final FunctionElement element;
@@ skipping 294 matching lines @@
       return internalError(node, "Unexpected variable $element.");
     }
     if (element.isConst) {
       ConstantExpression constant = elements.getConstant(element.initializer);
       return new ConstantVariableStructure(kind, node, element, constant);
     } else {
       return new NonConstantVariableStructure(kind, node, element);
     }
   }
 }