From 3a6f3354eaaf38b5e6be41e4ebf521d299593a6e Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Mon, 19 Feb 2024 11:34:45 -0500
Subject: [PATCH] c++: compound-requirement partial substitution [PR113966]
When partially substituting a requires-expr, we don't want to perform
any additional checks beyond the substitution itself so as to minimize
checking requirements out of order. So don't check the return-type-req
of a compound-requirement during partial substitution. And don't check
the noexcept condition either since we can't do that on templated trees.
PR c++/113966
gcc/cp/ChangeLog:
* constraint.cc (tsubst_compound_requirement): Don't check
the noexcept condition or the return-type-requirement when
partially substituting.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-friend17.C: New test.
Reviewed-by: Jason Merrill <jason@redhat.com>
---
gcc/cp/constraint.cc | 5 +++--
gcc/testsuite/g++.dg/cpp2a/concepts-friend17.C | 15 +++++++++++++++
2 files changed, 18 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-friend17.C
diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index d9569013bd34..49de3211d4c7 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -2134,7 +2134,8 @@ tsubst_compound_requirement (tree t, tree args, sat_info info)
/* Check the noexcept condition. */
bool noexcept_p = COMPOUND_REQ_NOEXCEPT_P (t);
- if (noexcept_p && !expr_noexcept_p (expr, quiet.complain))
+ if (noexcept_p && !processing_template_decl
+ && !expr_noexcept_p (expr, quiet.complain))
{
if (info.diagnose_unsatisfaction_p ())
inform (loc, "%qE is not %<noexcept%>", expr);
@@ -2148,7 +2149,7 @@ tsubst_compound_requirement (tree t, tree args, sat_info info)
return error_mark_node;
/* Check expression against the result type. */
- if (type)
+ if (type && !processing_template_decl)
{
if (tree placeholder = type_uses_auto (type))
{
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-friend17.C b/gcc/testsuite/g++.dg/cpp2a/concepts-friend17.C
new file mode 100644
index 000000000000..9b5091f14a81
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-friend17.C
@@ -0,0 +1,15 @@
+// PR c++/113966
+// { dg-do compile { target c++20 } }
+
+template<class T> concept C = T::value;
+
+template<class T>
+struct A {
+ template<class U> requires U::value || requires { { T() } -> C; }
+ friend void f(A, U) { }
+
+ template<class U> requires requires { { g(U()) } noexcept; }
+ friend void f(A, U, U) { }
+};
+
+template struct A<int>;
--
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