Add type inference for assert statements.

Add type inference for assert statements.

Note that since the first argument of an assert statement may be
either of type `bool` or `() -> bool`, and the second argument may be
any object, no type context is passed down in downward inference; the
only inference we need to do is to recursively invoke
`inferExpression` to ensure that subexpressions are inferred properly.

R=scheglov@google.com

Committed: https://github.com/dart-lang/sdk/commit/5cd3c2c8dc64f5faa683c37be7a16fdd8a1cee29

[Paul Berry, 2017-06-26 16:17:12]

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

[Paul Berry, 2017-06-26 16:17:13]

I only need a review from one of you.

[scheglov, 2017-06-26 16:19:14]

LGTM

[Paul Berry, 2017-06-26 17:05:13]

Description was changed from

==========
Add type inference for assert statements.

Note that since the first argument of an assert statement may be
either of type `bool` or `() -> bool`, and the second argument may be
any object, no type context is passed down in downward inference; the
only inference we need to do is to recursively invoke
`inferExpression` to ensure that subexpressions are inferred properly.
==========

to

==========
Add type inference for assert statements.

Note that since the first argument of an assert statement may be
either of type `bool` or `() -> bool`, and the second argument may be
any object, no type context is passed down in downward inference; the
only inference we need to do is to recursively invoke
`inferExpression` to ensure that subexpressions are inferred properly.

R=scheglov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/5cd3c2c8dc64f5faa683c37be7a16fdd8a1cee29
==========

[Paul Berry, 2017-06-26 17:05:14]

Committed patchset #1 (id:1) manually as
5cd3c2c8dc64f5faa683c37be7a16fdd8a1cee29 (presubmit successful).