Auto merge of #5000 - Eh2406:i4347, r=alexcrichton
authorbors <bors@rust-lang.org>
Thu, 1 Mar 2018 21:27:17 +0000 (21:27 +0000)
committerbors <bors@rust-lang.org>
Thu, 1 Mar 2018 21:27:17 +0000 (21:27 +0000)
backtrack if can not activate

This is a fix for #4347
Unfortunately this too regressed error messages for the case that you specified a dependency feature that does not  exist.
@alexcrichton advice on improving the message?

1  2 
tests/testsuite/resolve.rs

Simple merge