In check_methods we're unnecessarily checking satisfaction for all constructors and assignment operators, even those that don't look like copy/move special members. In the testcase below this manifests as an unstable satisfaction error because the satisfaction result is first determined to be false during check_methods (since A<int> is incomplete at this point) and later true after completion of A<int>.
This patch fixes this simply by swapping the order of the constraint_satisfied_p and copy_fn_p / move_fn_p tests. Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk? This doesn't fix the regression completely, since we get a similar unstable satisfaction error if one of the constrained members is actually a copy/move special member. I suppose we need to rearrange things in finish_struct_1 so that check_methods gets called in a complete class context? PR c++/108579 gcc/cp/ChangeLog: * class.cc (check_methods): Test constraints_satisfied_p after testing copy_fn_p / move_fn_p instead of beforehand. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-pr108579.C: New test. --- gcc/cp/class.cc | 16 ++++++++-------- gcc/testsuite/g++.dg/cpp2a/concepts-pr108579.C | 14 ++++++++++++++ 2 files changed, 22 insertions(+), 8 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-pr108579.C diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc index 351de6c5419..d3ce8532d56 100644 --- a/gcc/cp/class.cc +++ b/gcc/cp/class.cc @@ -4822,11 +4822,11 @@ check_methods (tree t) /* Might be trivial. */; else if (TREE_CODE (fn) == TEMPLATE_DECL) /* Templates are never special members. */; - else if (!constraints_satisfied_p (fn)) - /* Not eligible. */; - else if (copy_fn_p (fn)) + else if (copy_fn_p (fn) + && constraints_satisfied_p (fn)) TYPE_HAS_COMPLEX_COPY_CTOR (t) = true; - else if (move_fn_p (fn)) + else if (move_fn_p (fn) + && constraints_satisfied_p (fn)) TYPE_HAS_COMPLEX_MOVE_CTOR (t) = true; } @@ -4836,11 +4836,11 @@ check_methods (tree t) /* Might be trivial. */; else if (TREE_CODE (fn) == TEMPLATE_DECL) /* Templates are never special members. */; - else if (!constraints_satisfied_p (fn)) - /* Not eligible. */; - else if (copy_fn_p (fn)) + else if (copy_fn_p (fn) + && constraints_satisfied_p (fn)) TYPE_HAS_COMPLEX_COPY_ASSIGN (t) = true; - else if (move_fn_p (fn)) + else if (move_fn_p (fn) + && constraints_satisfied_p (fn)) TYPE_HAS_COMPLEX_MOVE_ASSIGN (t) = true; } } diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-pr108579.C b/gcc/testsuite/g++.dg/cpp2a/concepts-pr108579.C new file mode 100644 index 00000000000..bc7d709f889 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-pr108579.C @@ -0,0 +1,14 @@ +// PR c++/108579 +// { dg-do compile { target c++20 } } + +template<class T> +struct A { + A(double, char); + A(int) requires requires { A(0.0, 'c'); }; + A& operator=(int) requires requires { A(1.0, 'd'); }; +}; + +int main() { + A<int> x(3); + x = 5; +} -- 2.39.1.367.g5cc9858f1b