From b76d71564925abcabe6f5ad61d904b23c682cdfb Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Tue, 11 Jul 2023 10:05:19 -0400 Subject: [PATCH] c++: coercing variable template from current inst [PR110580] Here during ahead of time coercion of the variable template-id v1, since we pass only the innermost arguments to coerce_template_parms (and outer arguments are still dependent at this point), substitution of the default template argument V=U just lowers U from level 2 to level 1 rather than replacing it with int as expected. Thus after coercion we incorrectly end up with (effectively) v1 instead of v1. Coercion of a class/alias template-id on the other hand always passes all levels arguments, which avoids this issue. So this patch makes us do the same for variable template-ids. PR c++/110580 gcc/cp/ChangeLog: * pt.cc (lookup_template_variable): Pass all levels of arguments to coerce_template_parms, and use the parameters from the most general template. gcc/testsuite/ChangeLog: * g++.dg/cpp1y/var-templ83.C: New test. --- gcc/cp/pt.cc | 4 +++- gcc/testsuite/g++.dg/cpp1y/var-templ83.C | 16 ++++++++++++++++ 2 files changed, 19 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp1y/var-templ83.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 076f788281ef..fa15b75b9c54 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -10345,7 +10345,9 @@ lookup_template_variable (tree templ, tree arglist, tsubst_flags_t complain) if (flag_concepts && variable_concept_p (templ)) return build_concept_check (templ, arglist, tf_none); - tree parms = DECL_INNERMOST_TEMPLATE_PARMS (templ); + tree gen_templ = most_general_template (templ); + tree parms = DECL_INNERMOST_TEMPLATE_PARMS (gen_templ); + arglist = add_outermost_template_args (templ, arglist); arglist = coerce_template_parms (parms, arglist, templ, complain); if (arglist == error_mark_node) return error_mark_node; diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ83.C b/gcc/testsuite/g++.dg/cpp1y/var-templ83.C new file mode 100644 index 000000000000..f5268f258d77 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/var-templ83.C @@ -0,0 +1,16 @@ +// PR c++/110580 +// { dg-do compile { target c++14 } } + +template +struct A { + template + static constexpr bool v1 = __is_same(U, V); + + template + static constexpr bool v2 = !__is_same(U, V); + + static_assert(v1, ""); + static_assert(v2, ""); +}; + +template struct A; -- 2.47.2