Here, when we see the second declaration of f we match it with the first one, copy over DECL_TEMPLATE_INFO, and then try to use it when parsing the definition, leading to confusion.
Tested x86_64-pc-linux-gnu, applying to trunk. PR c++/105761 gcc/cp/ChangeLog: * decl.cc (duplicate_decls): Don't copy DECL_TEMPLATE_INFO from a hidden friend. gcc/testsuite/ChangeLog: * g++.dg/cpp1y/auto-fn64.C: New test. --- gcc/cp/decl.cc | 12 ++++++++++-- gcc/testsuite/g++.dg/cpp1y/auto-fn64.C | 12 ++++++++++++ 2 files changed, 22 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp1y/auto-fn64.C diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index e0d397d5a07..90b12d69414 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -2654,7 +2654,13 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden) if (LANG_DECL_HAS_MIN (newdecl)) { DECL_ACCESS (newdecl) = DECL_ACCESS (olddecl); - if (DECL_TEMPLATE_INFO (newdecl)) + if (new_defines_function + && DECL_TEMPLATE_INFO (olddecl) + && DECL_UNIQUE_FRIEND_P (DECL_TEMPLATE_RESULT + (DECL_TI_TEMPLATE (olddecl)))) + /* Don't copy template info from a non-template friend declaration + in a class template (PR105761). */; + else if (DECL_TEMPLATE_INFO (newdecl)) { new_template_info = DECL_TEMPLATE_INFO (newdecl); if (DECL_TEMPLATE_INSTANTIATION (olddecl) @@ -2662,8 +2668,10 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden) /* Remember the presence of explicit specialization args. */ TINFO_USED_TEMPLATE_ID (DECL_TEMPLATE_INFO (olddecl)) = TINFO_USED_TEMPLATE_ID (new_template_info); + DECL_TEMPLATE_INFO (newdecl) = DECL_TEMPLATE_INFO (olddecl); } - DECL_TEMPLATE_INFO (newdecl) = DECL_TEMPLATE_INFO (olddecl); + else + DECL_TEMPLATE_INFO (newdecl) = DECL_TEMPLATE_INFO (olddecl); } if (DECL_DECLARES_FUNCTION_P (newdecl)) diff --git a/gcc/testsuite/g++.dg/cpp1y/auto-fn64.C b/gcc/testsuite/g++.dg/cpp1y/auto-fn64.C new file mode 100644 index 00000000000..13f3175da45 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/auto-fn64.C @@ -0,0 +1,12 @@ +// PR c++/105761 +// { dg-do compile { target c++14 } } +// { dg-additional-options -Wno-non-template-friend } + +template <class T> +class X { + friend auto f(X); +}; + +struct Y : X<long> { + friend auto f(X) { return 0L; } +}; base-commit: 1982fe2692b6c3b7f969ffc4edac59f9d4359e91 -- 2.27.0