From c0b38e9fec71dc4cc5e99b1f0cb159c15a8da9ba Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Thu, 3 Nov 2022 14:55:35 -0400 Subject: [PATCH] c++: constexpr error with defaulted virtual dtor [PR93413] We're rejecting the below testcase with error: 'virtual constexpr Base::~Base()' used before its definition error: 'virtual constexpr Derived::~Derived()' used before its definition due to special handling in mark_used added by r181272 to defer synthesis of virtual destructors until EOF (where we can set their linkage), which in turn makes them effectively unusable during constexpr evaluation. Fortunately it seems this special handling is unnecessary ever since r208030 enabled us to tentatively set linkage of all defaulted virtual destructors, including templated ones. So this patch gets rid of this special handling. PR c++/93413 gcc/cp/ChangeLog: * decl2.cc (mark_used): Don't defer synthesis of virtual functions. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/constexpr-virtual21.C: New test. --- gcc/cp/decl2.cc | 8 -------- gcc/testsuite/g++.dg/cpp2a/constexpr-virtual21.C | 10 ++++++++++ 2 files changed, 10 insertions(+), 8 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-virtual21.C diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc index e677926..eeb59ea 100644 --- a/gcc/cp/decl2.cc +++ b/gcc/cp/decl2.cc @@ -5788,14 +5788,6 @@ mark_used (tree decl, tsubst_flags_t complain /* = tf_warning_or_error */) && !DECL_DEFAULTED_OUTSIDE_CLASS_P (decl) && ! DECL_INITIAL (decl)) { - /* Defer virtual destructors so that thunks get the right - linkage. */ - if (DECL_VIRTUAL_P (decl) && !at_eof) - { - note_vague_linkage_fn (decl); - return true; - } - /* Remember the current location for a function we will end up synthesizing. Then we can inform the user where it was required in the case of error. */ diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-virtual21.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-virtual21.C new file mode 100644 index 0000000..8b70c5f --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-virtual21.C @@ -0,0 +1,10 @@ +// PR c++/93413 +// { dg-do compile { target c++20 } } + +struct Base { + virtual ~Base() = default; +}; +constexpr Base b; + +struct Derived : Base { }; +constexpr Derived d; -- 2.7.4