swift234

Parser: Accept 'x as T!' as a synonym for '(x as T)!'.

Look for a postfix '!' after an 'as' production, and if we see it, carry it along in the CheckedCastExpr so we can wrap the cast in a ForceValueExpr once sequence folding resolves the LHS of the cast. Implements part of <rdar://problem/15640006>.

Swift SVN r15307