https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92049
--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Author: mpolacek Date: Fri Oct 11 20:44:02 2019 New Revision: 276906 URL: https://gcc.gnu.org/viewcvs?rev=276906&root=gcc&view=rev Log: PR c++/92049 - extra error with -fchecking=2. The concepts merge brought this bit @@ -26326,9 +26559,9 @@ build_non_dependent_expr (tree expr) unexpected recursive instantiations. */ && !parsing_nsdmi () /* Don't do this during concept expansion either and for - the same reason. */ - && !expanding_concept ()) - fold_non_dependent_expr (expr, tf_none); + the same reason. */ + && !parsing_constraint_expression_p ()) + fold_non_dependent_expr (expr); STRIP_ANY_LOCATION_WRAPPER (expr); (which I'm not finding in the ChangeLog). Dropping tf_none means that fold_non_dependent_expr will use tf_warning_or_error by default, and in this test that causes an error: template<bool> struct cond; template<int> struct S { void f(int i) { cond<__builtin_constant_p(i)>(); } }; S<1> s; where it complains that cond<false> is incomplete. Which it is, but we're not actually instantiating the function f, so issuing an error seems overzealous (though not wrong), and it breaks a bunch of tests. This patch brings that tf_none back. We will still complain if we do instantiate f. * pt.c (build_non_dependent_expr): Call fold_non_dependent_expr with tf_none. * g++.dg/template/builtin2.C: New test. Added: trunk/gcc/testsuite/g++.dg/template/builtin2.C Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/pt.c trunk/gcc/testsuite/ChangeLog
