From 352811870d7d7edcca109ef50822e26ca7ef2b36 Mon Sep 17 00:00:00 2001 From: Jason Merrill Date: Fri, 24 Apr 2020 16:27:26 -0400 Subject: [PATCH] c++: implicit operator== with previous decl [PR94583] P2085 clarified that a defaulted comparison operator must be the first declaration of the function. Rejecting that avoids the ICE trying to compare the noexcept-specifications. gcc/cp/ChangeLog 2020-04-24 Jason Merrill PR c++/94583 * decl.c (redeclaration_error_message): Reject defaulted comparison operator that has been previously declared. --- gcc/cp/ChangeLog | 6 ++++++ gcc/cp/decl.c | 8 ++++++++ gcc/testsuite/g++.dg/cpp2a/spaceship-synth6.C | 11 +++++++++++ 3 files changed, 25 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth6.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 2a5b4171366..f0c62783101 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,9 @@ +2020-04-24 Jason Merrill + + PR c++/94583 + * decl.c (redeclaration_error_message): Reject defaulted comparison + operator that has been previously declared. + 2020-04-25 Patrick Palka * parser.c (cp_parser_diagnose_invalid_type_name): Suggest enabling diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index c8c2f080763..31b5884ca3a 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -2972,6 +2972,14 @@ redeclaration_error_message (tree newdecl, tree olddecl) } } + /* [class.compare.default]: A definition of a comparison operator as + defaulted that appears in a class shall be the first declaration of + that function. */ + special_function_kind sfk = special_function_p (olddecl); + if (sfk == sfk_comparison && DECL_DEFAULTED_FN (newdecl)) + return G_("comparison operator %q+D defaulted after " + "its first declaration"); + check_abi_tag_redeclaration (olddecl, lookup_attribute ("abi_tag", DECL_ATTRIBUTES (olddecl)), lookup_attribute ("abi_tag", DECL_ATTRIBUTES (newdecl))); diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth6.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth6.C new file mode 100644 index 00000000000..e8296bbb60a --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth6.C @@ -0,0 +1,11 @@ +// PR c++/94583 +// { dg-do compile { target c++2a } } + +namespace std { struct strong_ordering { }; } + +bool operator==(const struct Q&, const struct Q&); +struct Q { + // { dg-error "defaulted after its first declaration" "" { target *-*-* } .+1 } + friend std::strong_ordering operator<=>(const Q&, const Q&) = default; +}; +bool b = Q() == Q(); -- 2.30.2