fix #27454, prune FunctionTypeImpl.parameters

fix #27454, prune FunctionTypeImpl.parameters

without this, using ".parameters" resulted in inconsistent types compared with ".returnType" ".*parameterTypes" and other APIs.

R=vsm@google.com

Committed: https://github.com/dart-lang/sdk/commit/2e80071cfec6062934ae98a34d331bba14bf3d62

[Jennifer Messerly, 2016-09-29 21:17:04]

jmesserly@google.com changed reviewers:
+ leafp@google.com, vsm@google.com

[Jennifer Messerly, 2016-09-29 21:17:05]

This fixes a test caught by DDC's travis.

The failure was caused by removing "==" from strong subtype, however that's not
the real bug. The bug is introduced anywhere we use
"FunctionTypeImpl.parameters" in particular this is now used in
FunctionTypeImpl.relate.

Pretty much the entire value of FunctionTypeImpl.parameters is to return a List
of ParameterElements with their types adjusted, so we include the pruning now.
Otherwise, any use of ".parameters" is a stack overflow waiting to happen in the
case of cyclic typedefs.

I don't think it is possible to need pruning for FieldFormalParameterMembers,
but admittedly the lazy-pruning approach is pretty awkward, so I don't
understand it 100%

[vsm, 2016-09-29 22:00:14]

lgtm

[Jennifer Messerly, 2016-09-29 22:54:31]

Description was changed from

==========
fix #27454, prune FunctionTypeImpl.parameters

without this, using ".parameters" resulted in inconsistent types compared with
".returnType" ".*parameterTypes" and other APIs.
==========

to

==========
fix #27454, prune FunctionTypeImpl.parameters

without this, using ".parameters" resulted in inconsistent types compared with
".returnType" ".*parameterTypes" and other APIs.

R=vsm@google.com

Committed:
https://github.com/dart-lang/sdk/commit/2e80071cfec6062934ae98a34d331bba14bf3d62
==========

[Jennifer Messerly, 2016-09-29 22:54:32]

Committed patchset #2 (id:20001) manually as
2e80071cfec6062934ae98a34d331bba14bf3d62 (presubmit successful).