Don't generate errors when failing to follow const constructor redirections.

Don't generate errors when failing to follow const constructor redirections.

In two cases (circular redirections and redirecting to a non-const
constructor), the error has already been reported.  The third case
(external factory constructor) is not an error condition.

Fixes test lib/_internal/compiler/samples/jsonify/jsonify.

BUG=
R=brianwilkerson@google.com

Committed: https://code.google.com/p/dart/source/detail?r=35877

[Brian Wilkerson, 2014-05-07 17:41:06]

LGTM

https://codereview.chromium.org/273703003/diff/1/editor/tools/plugins/com.goo...
File
editor/tools/plugins/com.google.dart.engine_test/src/com/google/dart/engine/internal/constant/ConstantVisitorTest.java
(right):

https://codereview.chromium.org/273703003/diff/1/editor/tools/plugins/com.goo...
editor/tools/plugins/com.google.dart.engine_test/src/com/google/dart/engine/internal/constant/ConstantVisitorTest.java:193:
assertEquals("int", value.getType().getName());
Should we add "assertFalse(value.isUnknown());" or would that be unnecessary?

[Paul Berry, 2014-05-08 00:08:59]

https://codereview.chromium.org/273703003/diff/1/editor/tools/plugins/com.goo...
File
editor/tools/plugins/com.google.dart.engine_test/src/com/google/dart/engine/internal/constant/ConstantVisitorTest.java
(right):

https://codereview.chromium.org/273703003/diff/1/editor/tools/plugins/com.goo...
editor/tools/plugins/com.google.dart.engine_test/src/com/google/dart/engine/internal/constant/ConstantVisitorTest.java:193:
assertEquals("int", value.getType().getName());
On 2014/05/07 17:41:06, Brian Wilkerson wrote:
> Should we add "assertFalse(value.isUnknown());" or would that be unnecessary?

I don't think it's necessary.  In the event of an unknown value,
value.getIntValue() will return null, so we'll get a NPE, and that should be
easy enough to debug.

[Paul Berry, 2014-05-08 00:24:40]

Committed patchset #1 manually as r35877 (presubmit successful).