Fix a bug in how we deal HTypeConversion during type propagation: we must use the intersection betw…

Fix a bug in how we deal HTypeConversion during type propagation: we can only convert to int if the input is int or null.

R=kasperl@google.com

Committed: https://code.google.com/p/dart/source/detail?r=24230

[kasperl, 2013-06-19 07:26:11]

LGTM.

[ngeoffray, 2013-06-19 13:23:00]

Thanks Kasper, could you PTAL? There were two mistakes in the original CL: 1) we
should not change the type a checked mode checks for, and 2) we have to deal
with a conflicting type conversion when generating code and optimizing.

[ngeoffray, 2013-06-19 14:16:12]

On 2013/06/19 13:23:00, ngeoffray wrote:
> Thanks Kasper, could you PTAL? There were two mistakes in the original CL: 1)
we
> should not change the type a checked mode checks for, and 2) we have to deal
> with a conflicting type conversion when generating code and optimizing.

Scratch that, doing the intersection was wrong in the first place. So I decided
to just special case the conversion from int or null to number to avoid the
problem.

[kasperl, 2013-06-20 06:30:44]

LGTM.

[ngeoffray, 2013-06-20 14:10:58]

Committed patchset #5 manually as r24230 (presubmit successful).