resolve: change most backwards incompatible ambiguity errors to `legacy_imports` warnings#38271

Merged

bors merged 1 commit intorust-lang:masterfrom jseyfried:rfc_1560_warning_cycle

Dec 20, 2016

+111-28

Commits on Dec 15, 2016

Demote most backwards incompatible ambiguity errors from RFC 1560 to warnings.
jseyfried
committed