Hi!
As discussed on IRC, defaulted comparison operators were added only in
C++2a, so we shouldn't accept it in older standard modes.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2019-12-17 Jakub Jelinek <ja...@redhat.com>
PR c++/92973
* method.c (early_check_defaulted_comparison): For C++17 and earlier
diagnose defaulted comparison operators.
* g++.dg/cpp0x/spaceship-eq1.C: New test.
--- gcc/cp/method.c.jj 2019-12-17 15:28:57.819285145 +0100
+++ gcc/cp/method.c 2019-12-17 16:21:24.462870308 +0100
@@ -1092,6 +1092,13 @@ early_check_defaulted_comparison (tree f
ctx = DECL_FRIEND_CONTEXT (fn);
bool ok = true;
+ if (cxx_dialect < cxx2a)
+ {
+ error_at (loc, "defaulted %qD only available with %<-std=c++2a%> or "
+ "%<-std=gnu++2a%>", fn);
+ return false;
+ }
+
if (!DECL_OVERLOADED_OPERATOR_IS (fn, SPACESHIP_EXPR)
&& !same_type_p (TREE_TYPE (TREE_TYPE (fn)), boolean_type_node))
{
--- gcc/testsuite/g++.dg/cpp0x/spaceship-eq1.C.jj 2019-12-17
16:24:55.303697061 +0100
+++ gcc/testsuite/g++.dg/cpp0x/spaceship-eq1.C 2019-12-17 16:24:29.070091886
+0100
@@ -0,0 +1,5 @@
+// PR c++/92973
+// { dg-do compile { target c++11 } }
+
+struct S { bool operator==(const S&) const = default; int s; }; // {
dg-error "only available with" "" { target c++17_down } }
+struct T { bool operator!=(const T&) const = default; int t; }; // {
dg-error "only available with" "" { target c++17_down } }
Jakub
