From: Patrick Palka <ppalka@redhat.com>
To: gcc-patches@gcc.gnu.org
Subject: [PATCH] c++: Overeager use of deleted function before ADL [PR68942]
Date: Wed, 28 Apr 2021 15:03:09 -0400 [thread overview]
Message-ID: <20210428190309.4143566-1-ppalka@redhat.com> (raw)
Here, at template definition time, ordinary name lookup for 'foo(t)'
finds the deleted function, and so we form a CALL_EXPR thereof. Later
at instantiation time, when initially substituting into this CALL_EXPR
with T=N::A, we end up calling mark_used on this deleted function before
we augment the overload set via ADL and select the right function.
This patch fixes this issue by using tf_conv in order to disable
mark_used during the initial substitution of the function of a CALL_EXPR
when KOENIG_P.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk?
gcc/cp/ChangeLog:
PR c++/68942
* pt.c (tsubst_copy_and_build) <case CALL_EXPR>: When KOENIG_P,
add tf_conv to complain during the initial substitution into
the function.
gcc/testsuite/ChangeLog:
PR c++/68942
* g++.dg/template/koenig12.C: New test.
---
gcc/cp/pt.c | 6 +++++-
gcc/testsuite/g++.dg/template/koenig12.C | 15 +++++++++++++++
2 files changed, 20 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/template/koenig12.C
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index d79fecd4949..bed9a22193a 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -20238,7 +20238,11 @@ tsubst_copy_and_build (tree t,
/* Avoid error about taking the address of a constructor. */
function = TREE_OPERAND (function, 0);
- function = tsubst_copy_and_build (function, args, complain,
+ /* When KOENIG_P, we don't want to mark_used a function until
+ after performing ADL, during this substitution we disable
+ mark_used by adding tf_conv to complain (68942). */
+ function = tsubst_copy_and_build (function, args,
+ complain | (koenig_p * tf_conv),
in_decl,
!qualified_p,
integral_constant_expression_p);
diff --git a/gcc/testsuite/g++.dg/template/koenig12.C b/gcc/testsuite/g++.dg/template/koenig12.C
new file mode 100644
index 00000000000..fd05ef5719e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/koenig12.C
@@ -0,0 +1,15 @@
+// PR c++/68942
+// { dg-do compile { target c++11 } }
+
+void foo(...) = delete;
+
+template <class T> void lookup(T t) { foo(t); }
+
+namespace N {
+ struct A { };
+ int foo(A);
+}
+
+int main() {
+ lookup(N::A{});
+}
--
2.31.1.362.g311531c9de
next reply other threads:[~2021-04-28 19:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-28 19:03 Patrick Palka [this message]
2021-04-29 13:46 ` Jason Merrill
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