https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96299
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:4ed1dc1275bba89af92bfc7d97c21b376e4c29c3 commit r11-5866-g4ed1dc1275bba89af92bfc7d97c21b376e4c29c3 Author: Jason Merrill <ja...@redhat.com> Date: Fri Dec 4 21:48:43 2020 -0500 c++: Fix defaulted <=> fallback to < and == [PR96299] I thought I had implemented P1186R3, but apparently I didn't read it closely enough to understand the point of the paper, namely that for a defaulted operator<=>, if a member type doesn't have a viable operator<=>, we will use its operator< and operator== if the defaulted operator has an specific comparison category as its return type; the compiler can't guess if it should be strong_ordering or something else, but the user can make that choice explicit. The libstdc++ test change was necessary because of the change in genericize_spaceship from op0 > op1 to op1 < op0; this should be equivalent, but isn't because of PR88173. gcc/cp/ChangeLog: PR c++/96299 * cp-tree.h (build_new_op): Add overload that omits some parms. (genericize_spaceship): Add location_t parm. * constexpr.c (cxx_eval_binary_expression): Pass it. * cp-gimplify.c (genericize_spaceship): Pass it. * method.c (genericize_spaceship): Handle class-type arguments. (build_comparison_op): Fall back to op</== when appropriate. gcc/testsuite/ChangeLog: PR c++/96299 * g++.dg/cpp2a/spaceship-synth-neg2.C: Move error. * g++.dg/cpp2a/spaceship-p1186.C: New test. libstdc++-v3/ChangeLog: PR c++/96299 * testsuite/18_support/comparisons/algorithms/partial_order.cc: One more line needs to use VERIFY instead of static_assert.
