From: Patrick Palka <ppalka@redhat.com>
To: gcc-patches@gcc.gnu.org
Cc: jason@redhat.com, Patrick Palka <ppalka@redhat.com>
Subject: [PATCH] c++: excessive satisfaction in check_methods [PR108579]
Date: Mon, 30 Jan 2023 14:10:38 -0500 [thread overview]
Message-ID: <20230130191038.2450035-1-ppalka@redhat.com> (raw)
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
next reply other threads:[~2023-01-30 19:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-30 19:10 Patrick Palka [this message]
2023-02-02 22:46 ` Jason Merrill
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