Fixing 2 issues. A test for __is_convertible_to was missing in diagnose_trait, and *somehow* the logic for determining constraint ordering w.r.t. requires expressions was missing.
Committed in 203826. 2013-10-16 Andrew Sutton <andrew.n.sut...@gmail.com> * gcc/cp/logic.cc (left_requires), (decompose_left): Add decomposition rules for requires expressions. (subsumes_requires), (subsumes_prop): Add subsumption rules for requires expressions. * gcc/cp/constraint.cc (diagnose_trait): Diagnose failed conversion requirements. Andrew