On Sat, Apr 25, 2020 at 12:17:18AM -0400, Jason Merrill via Gcc-patches wrote: > 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. > > Tested x86_64-pc-linux-gnu, applying to trunk. > > gcc/cp/ChangeLog > 2020-04-24 Jason Merrill <ja...@redhat.com> > > PR c++/94583 > * decl.c (redeclaration_error_message): Reject defaulted comparison > operator that has been previously declared. > --- > gcc/cp/decl.c | 8 ++++++++ > gcc/testsuite/g++.dg/cpp2a/spaceship-synth6.C | 11 +++++++++++ > 2 files changed, 19 insertions(+) > create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth6.C > > 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"); > +
This one still ICEs: namespace std { struct strong_ordering { }; } struct Q { friend std::strong_ordering operator<=>(const Q&, const Q&) = default; }; bool operator==(const Q&, const Q&) noexcept; Either we need to reject redeclaring the implicit operator==, or teach get_defaulted_eh_spec how to handle its DEFERRED_NOEXCEPT, before build_comparison_op/~comp_info resolves it, because otherwise we couldn't check that the noexcept-specifications match. Thoughts? Marek