https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92236
--- Comment #7 from asutton at gcc dot gnu.org --- Author: asutton Date: Wed Nov 27 15:23:02 2019 New Revision: 278775 URL: https://gcc.gnu.org/viewcvs?rev=278775&root=gcc&view=rev Log: 2019-11-27 Andrew Sutton <asut...@lock3software.com> PR c++/92236 Defer evaluation of concept checks so that static assertions can emit more detailed diagnostics. gcc/cp/ * constexpr.c (cxx_eval_call_expression): Handle concept checks. (cxx_eval_constant_expression): Diagnose misuse of function concepts as template-id expressions. Follow the usual return path for results. (cxx_eval_outermost_constant_expr): Avoid calling cp_get_callee_fndecl_nofold for function concepts. * constraint.cc (build_function_check): Fully type the concept check so that we don't ICE in conversions. * cp-gimplify.c (cp_genericize_r) [CALL_EXPR]: Handle concept checks. [TEMPLATE_ID_EXPR] Likewise. * cvt.c (convert_to_void): Always evaluate concept checks so we don't accidentally ignore them. Substitution during satisfaction can make a program ill-formed (example in g++.dg/cpp2a/concepts6.C). * pt.c (tsubst_copy_and_build): [CALL_EXPR]: Don't evaluate concepts. [TEMPLATE_ID_EXPR]: Likewise. * semantics.c (finish_call_expr): Don't evaluate concepts. (finish_id_expression_1): Likewise. (finish_static_assert): Preserve the original condition so we can diagnose concept errors when a check returns false. gcc/testsuite/ * g++.dg/cpp2a/concepts-iconv1.C: Update diagnostics. * g++.dg/cpp2a/concepts-requires5.C: Likewise. * g++.dg/cpp2a/concepts6.C: New test. Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/constexpr.c trunk/gcc/cp/constraint.cc trunk/gcc/cp/cp-gimplify.c trunk/gcc/cp/cvt.c trunk/gcc/cp/pt.c trunk/gcc/cp/semantics.c trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/g++.dg/cpp2a/concepts-iconv1.C trunk/gcc/testsuite/g++.dg/cpp2a/concepts-requires5.C
