From a8b3861496bffae8b813ea196c1c5b27f79fbe69 Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Fri, 16 Jul 2021 16:21:13 -0400 Subject: [PATCH] c++: alias CTAD in unevaluated context [PR101233] This is the alias CTAD version of the CTAD bug PR93248, and the fix is the same: clear cp_unevaluated_operand so that the entire chain of DECL_ARGUMENTS gets substituted. PR c++/101233 gcc/cp/ChangeLog: * pt.c (alias_ctad_tweaks): Clear cp_unevaluated_operand for substituting DECL_ARGUMENTS. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/class-deduction-alias10.C: New test. --- gcc/cp/pt.c | 8 +++++++- gcc/testsuite/g++.dg/cpp2a/class-deduction-alias10.C | 10 ++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/class-deduction-alias10.C diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index c7bf7d4..94ca3bc 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -29097,7 +29097,13 @@ alias_ctad_tweaks (tree tmpl, tree uguides) /* Substitute the deduced arguments plus the rewritten template parameters into f to get g. This covers the type, copyness, guideness, and explicit-specifier. */ - tree g = tsubst_decl (DECL_TEMPLATE_RESULT (f), targs, complain); + tree g; + { + /* Parms are to have DECL_CHAIN tsubsted, which would be skipped + if cp_unevaluated_operand. */ + cp_evaluated ev; + g = tsubst_decl (DECL_TEMPLATE_RESULT (f), targs, complain); + } if (g == error_mark_node) continue; DECL_USE_TEMPLATE (g) = 0; diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias10.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias10.C new file mode 100644 index 0000000..a473fff --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias10.C @@ -0,0 +1,10 @@ +// PR c++/101233 +// { dg-do compile { target c++20 } } + +template +struct A { A(T, U); }; + +template +using B = A; + +using type = decltype(B{0, 0}); -- 2.7.4