swift234

Parse 'as' and 'is' as sequence exprs.

Treat 'as' and 'is' as fixed-precedence binary operators, like we now do '=' and '? ... :'. However, since 'as' and 'is' max-munch-parse a type name on their RHS, we only parse them at the tail end of a SequenceExpr. This not only makes 'a = b as T' work as expected again, but also makes 'a += b as T' work, fixing <rdar://problem/13772819>.

Swift SVN r5514