In constant evaluation, properly handle redirecting factory constructors.

tests/language/switch_case_test.dart

 // Copyright (c) 2014, 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.
 
 import "package:expect/expect.dart";
 
 class A {
   const A();
   const factory A.B() = B;
   const factory A.C() = C;
   const factory A.C2() = D;
 }
 
 class B implements A {
   const B();
 
   operator ==(o) => true;  /// 00: compile-time error
 }
 
 class C implements A {
   final int x;
   const C() : x = 0;
   const C.fromD() : x = 1;
 }
 
 class D implements C {
+  int get x => 0;

[Brian Wilkerson, 2014/05/06 21:44:32]

I don't know enough about this test to know whether the absence of this line was
significant (although I admit it seems unlikely in this case). We should
probably get the author to review the change.

   const factory D() = C.fromD;
 }
 
 main() {
   switch (new B()) {
     case const A.B(): Expect.fail("bad switch"); break;  /// 00: continued
   }
 
   switch (new C()) {
     case const C(): Expect.fail("bad switch"); break;
     case const A.C(): Expect.fail("bad switch"); break;
     case const A.C2(): Expect.fail("bad switch"); break;
     case const A(): Expect.fail("bad switch"); break;  /// 01: compile-time error
   }
 
   switch (new A()) {
     case const A(): Expect.fail("bad switch"); break;
     case const A.B(): Expect.fail("bad switch"); break;  /// 02: compile-time error
   }
 }