swift234

Fix a crash on invalid I ran into while working on other stuff.  Previously 
we would type check the argument patterns... and if there was an error, skip
type checking the body patterns.  This caused problems later with unset types.

Now we make sure to type check them both, but if there is an error in the arg
pattern, we just recursively set the corresponding body pattern's types to 
errortype to avoid emitting redundant diagnostics.



Swift SVN r13916