Ensure fail expression is walked, and make fail with a non-string expression fail typechecking.#617

Closed

jdm wants to merge 3 commits intorust-lang:masterfrom

jdm:fail-str-addendum

Commits on Jul 3, 2011

Commits on Jul 4, 2011

Make use of demand::simple instead of manually checking fail expr type.
jdm
committed