Alex Crichton 9c330529f2
Fix codegen for descriptors of async fn returns (#1782)
They erroneously reported returning the original return type, not the
promise! Let's also add a bunch of positive tests while we're at it.

Closes #1781
2019-09-20 16:06:27 -05:00
..
2019-08-19 04:21:27 -07:00