https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104620
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:647537adefb34041cc2d44585252fd765cc0daae commit r12-7802-g647537adefb34041cc2d44585252fd765cc0daae Author: Patrick Palka <ppa...@redhat.com> Date: Thu Mar 24 11:42:31 2022 -0400 c++: missing SFINAE for non-constant consteval calls [PR104620] Here we weren't respecting SFINAE when evaluating a call to a consteval function, which caused us to reject the new testcase below. This patch fixes this by making build_over_call use the SFINAE-friendly version of cxx_constant_value. This change causes us to no longer diagnose ahead of time a couple of non-constant non-dependent consteval calls in consteval-if2.C with -fchecking=2. These errors were apparently coming from the call to fold_non_dependent_expr in build_non_dependent_expr (for the RHS of the +=) despite complain=tf_none being passed. Now that build_over_call respects the value of complain during constant evaluation of a consteval call, the errors are gone. That the errors are also gone without -fchecking=2 is a regression caused by r12-7264-gc19f317a78c0e4 and is the subject of PR104620. As described in comment #5, I think it's basically an accident that we were diagnosing these two calls correctly before r12-7264, so perhaps we can live without these errors for GCC 12. Thus this patch just XFAILs the two tests. PR c++/104620 gcc/cp/ChangeLog: * call.cc (build_over_call): Use cxx_constant_value_sfinae instead of cxx_constant_value to evaluate a consteval call. * constexpr.cc (cxx_constant_value_sfinae): Add decl parameter and pass it to cxx_eval_outermost_constant_expr. * cp-tree.h (cxx_constant_value_sfinae): Add decl parameter. * pt.cc (fold_targs_r): Pass NULL_TREE as decl parameter to cxx_constant_value_sfinae. gcc/testsuite/ChangeLog: * g++.dg/cpp23/consteval-if2.C: XFAIL two dg-error tests where the argument to the non-constant non-dependent consteval call is wrapped by NON_DEPENDENT_EXPR. * g++.dg/cpp2a/consteval30.C: New test.
