From 42f9b481be3527b336b800128247d053fd18d121 Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Thu, 11 May 2023 10:04:25 -0400
Subject: [PATCH] c++: converted lambda as template argument [PR83258, ...]
r8-1253-g3d2e25a240c711 removed the template argument linkage requirement
in convert_nontype_argument for C++17 (which r9-3836-g4be5c72cf3ea3e later
factored out into invalid_tparm_referent_p), but we need to also remove
the one in convert_nontype_argument_function for benefit of the first and
third testcase which we currently reject even in C++17/20 mode.
And in invalid_tparm_referent_p we're inadvertendly returning false for
the address of a lambda's static op() since it's DECL_ARTIFICIAL, which
currently causes us to reject the second (C++20) testcase. But this
DECL_ARTIFICIAL check seems to be relevant only for VAR_DECL, and in fact
this code path was originally reachable only for VAR_DECL until recently
(r13-6970-gb5e38b1c166357). So this patch restricts the check to VAR_DECL.
Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
PR c++/83258
PR c++/80488
PR c++/97700
gcc/cp/ChangeLog:
* pt.cc (convert_nontype_argument_function): Remove linkage
requirement for C++17 and later.
(invalid_tparm_referent_p) <case ADDR_EXPR>: Restrict
DECL_ARTIFICIAL rejection test to VAR_DECL.
gcc/testsuite/ChangeLog:
* g++.dg/ext/visibility/anon8.C: Don't expect a "no linkage"
error for the template argument &B2:fn in C++17 mode.
* g++.dg/cpp0x/lambda/lambda-conv15.C: New test.
* g++.dg/cpp2a/nontype-class56.C: New test.
* g++.dg/template/function2.C: New test.
(cherry picked from commit c3afdb8ba8f1839544c414f57e41a58c8fda5349)
---
gcc/cp/pt.cc | 5 +++--
gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv15.C | 11 +++++++++++
gcc/testsuite/g++.dg/cpp2a/nontype-class56.C | 8 ++++++++
gcc/testsuite/g++.dg/ext/visibility/anon8.C | 4 ++--
gcc/testsuite/g++.dg/template/function2.C | 8 ++++++++
5 files changed, 32 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv15.C
create mode 100644 gcc/testsuite/g++.dg/cpp2a/nontype-class56.C
create mode 100644 gcc/testsuite/g++.dg/template/function2.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index ad4ccba3a3bd..9128f15f41bc 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -6780,7 +6780,8 @@ convert_nontype_argument_function (tree type, tree expr,
}
linkage = decl_linkage (fn_no_ptr);
- if (cxx_dialect >= cxx11 ? linkage == lk_none : linkage != lk_external)
+ if ((cxx_dialect < cxx11 && linkage != lk_external)
+ || (cxx_dialect < cxx17 && linkage == lk_none))
{
if (complain & tf_error)
{
@@ -7178,7 +7179,7 @@ invalid_tparm_referent_p (tree type, tree expr, tsubst_flags_t complain)
* a string literal (5.13.5),
* the result of a typeid expression (8.2.8), or
* a predefined __func__ variable (11.4.1). */
- else if (DECL_ARTIFICIAL (decl))
+ else if (VAR_P (decl) && DECL_ARTIFICIAL (decl))
{
if (complain & tf_error)
error ("the address of %qD is not a valid template argument",
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv15.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv15.C
new file mode 100644
index 000000000000..cf45e06a33d3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv15.C
@@ -0,0 +1,11 @@
+// PR c++/83258
+// PR c++/80488
+// { dg-do compile { target c++11 } }
+
+template<void(*)()> struct A { };
+
+int main() {
+ constexpr auto fp = +[]{}; // { dg-error "non-'constexpr' function" "" { target c++14_down } }
+ A<fp> a1; // { dg-error "not a valid template argument" "" { target c++14_down } }
+ A<[]{}> a2; // { dg-error "lambda-expression in template-argument|invalid" "" { target c++17_down } }
+}
diff --git a/gcc/testsuite/g++.dg/cpp2a/nontype-class56.C b/gcc/testsuite/g++.dg/cpp2a/nontype-class56.C
new file mode 100644
index 000000000000..0efd735c8a34
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/nontype-class56.C
@@ -0,0 +1,8 @@
+// PR c++/97700
+// { dg-do compile { target c++20 } }
+
+struct S { void (*f)(); };
+
+template<S> struct X { };
+
+X<S{[]{}}> x;
diff --git a/gcc/testsuite/g++.dg/ext/visibility/anon8.C b/gcc/testsuite/g++.dg/ext/visibility/anon8.C
index b8507497d32c..bfcc2d06df66 100644
--- a/gcc/testsuite/g++.dg/ext/visibility/anon8.C
+++ b/gcc/testsuite/g++.dg/ext/visibility/anon8.C
@@ -2,7 +2,7 @@
// { dg-do compile }
template <void (*fn) ()>
-void call () // { dg-message "note" }
+void call () // { dg-message "note" "" { target c++14_down } }
{
fn ();
}
@@ -26,7 +26,7 @@ int main ()
static void fn2 () {}
};
call<&B1::fn1> ();
- call<&B2::fn2> (); // { dg-error "linkage|no matching" }
+ call<&B2::fn2> (); // { dg-error "linkage|no matching" "" { target c++14_down } }
call<&fn3> ();
call<&B1::fn4> ();
call<&fn5> (); // { dg-error "linkage|no matching" "" { target { ! c++11 } } }
diff --git a/gcc/testsuite/g++.dg/template/function2.C b/gcc/testsuite/g++.dg/template/function2.C
new file mode 100644
index 000000000000..54c48e6b36f4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/function2.C
@@ -0,0 +1,8 @@
+// PR c++/83258
+
+template<void(*)()> struct A { };
+
+int main() {
+ struct B { static void f() { } };
+ A<B::f> a; // { dg-error "linkage" "" { target c++14_down } }
+}
--
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