Access types safely in TypeResolverVisior.visitMethodDeclaration()

Access types safely in TypeResolverVisior.visitMethodDeclaration()

Previously, when attempting to figure out the type of the synthetic
field associated with a getter (or setter),
TypeResolverVisitor.visitMethodDeclaration() used the getters
FunctionTypeImpl.returnType (or FunctionTypeImpl.normalParameterTypes)
to extract the appropriate type.  But those getters are only safe to
use after types have been fully constructed (because they may try to
perform type substitution).  Fortunately, type substitution isn't
needed here, so we can simply use FunctionTypeImpl.baseReturnType (or
FunctionTypeImpl.baseParameters) instead.

Fixes #24539.

R=brianwilkerson@google.com, scheglov@google.com

Committed: https://github.com/dart-lang/sdk/commit/9af099fcdfd931a0064681f40c6d553ca88a439b

[Paul Berry, 2015-10-09 20:47:00]

paulberry@google.com changed reviewers:
+ brianwilkerson@google.com, scheglov@google.com

[scheglov, 2015-10-09 21:11:50]

LGTM

[Brian Wilkerson, 2015-10-09 21:15:06]

LGTM

[Paul Berry, 2015-10-09 21:21:16]

Committed patchset #1 (id:1) manually as
9af099fcdfd931a0064681f40c6d553ca88a439b (presubmit successful).