From f31dd9beb95f4beda1d2bd5c0526c42d0ce455c4 Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Wed, 29 Jul 2020 22:06:36 -0400 Subject: [PATCH] c++: abbreviated function template friend matching [PR96106] In the below testcase, duplicate_decls wasn't merging the tsubsted friend declaration for 'void add(auto)' with its definition, because reduce_template_parm_level (during tsubst_friend_function) lost the DECL_VIRTUAL_P flag on the auto's invented template parameter, which caused template_heads_equivalent_p to deem the two template heads as not equivalent in C++20 mode. This patch makes reduce_template_parm_level carry over the DECL_VIRTUAL_P flag from the original TEMPLATE_PARM_DECL. gcc/cp/ChangeLog: PR c++/96106 * pt.c (reduce_template_parm_level): Propagate DECL_VIRTUAL_P from the original TEMPLATE_PARM_DECL to the new lowered one. gcc/testsuite/ChangeLog: PR c++/96106 * g++.dg/concepts/abbrev7.C: New test. --- gcc/cp/pt.c | 1 + gcc/testsuite/g++.dg/concepts/abbrev7.C | 14 ++++++++++++++ 2 files changed, 15 insertions(+) create mode 100644 gcc/testsuite/g++.dg/concepts/abbrev7.C diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 9b4e6ce7d89..15be7b6d972 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -4453,6 +4453,7 @@ reduce_template_parm_level (tree index, tree type, int levels, tree args, type); TREE_CONSTANT (decl) = TREE_CONSTANT (orig_decl); TREE_READONLY (decl) = TREE_READONLY (orig_decl); + DECL_VIRTUAL_P (decl) = DECL_VIRTUAL_P (orig_decl); DECL_ARTIFICIAL (decl) = 1; SET_DECL_TEMPLATE_PARM_P (decl); diff --git a/gcc/testsuite/g++.dg/concepts/abbrev7.C b/gcc/testsuite/g++.dg/concepts/abbrev7.C new file mode 100644 index 00000000000..443c1b7871b --- /dev/null +++ b/gcc/testsuite/g++.dg/concepts/abbrev7.C @@ -0,0 +1,14 @@ +// PR c++/96106 +// { dg-do compile { target concepts } } + +template +struct number { + friend void add(auto); +}; + +void add(auto) { } + +void foo() { + number n; + add(n); // { dg-bogus "ambiguous" } +} -- 2.30.2