c++: is_specialization_of_friend confusion [PR109923]
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Commit Message
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk?
-- >8 --
The check for a non-template member function of a class template in
is_specialization_of_friend is overbroad, and accidentally holds for a
non-template hidden friend too, which causes the predicate to return
true for
decl = void non_templ_friend(A<int>, A<void>)
friend_decl = void non_templ_friend(A<void>, A<void>)
This patch refines the check appropriately.
PR c++/109923
gcc/cp/ChangeLog:
* pt.cc (is_specialization_of_friend): Fix overbroad check for
a non-template member function of a class template.
gcc/testsuite/ChangeLog:
* g++.dg/template/friend79.C: New test.
---
gcc/cp/pt.cc | 1 +
gcc/testsuite/g++.dg/template/friend79.C | 20 ++++++++++++++++++++
2 files changed, 21 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/template/friend79.C
Comments
On 6/2/23 10:29, Patrick Palka wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk?
OK.
> -- >8 --
>
> The check for a non-template member function of a class template in
> is_specialization_of_friend is overbroad, and accidentally holds for a
> non-template hidden friend too, which causes the predicate to return
> true for
>
> decl = void non_templ_friend(A<int>, A<void>)
> friend_decl = void non_templ_friend(A<void>, A<void>)
>
> This patch refines the check appropriately.
>
> PR c++/109923
>
> gcc/cp/ChangeLog:
>
> * pt.cc (is_specialization_of_friend): Fix overbroad check for
> a non-template member function of a class template.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/template/friend79.C: New test.
> ---
> gcc/cp/pt.cc | 1 +
> gcc/testsuite/g++.dg/template/friend79.C | 20 ++++++++++++++++++++
> 2 files changed, 21 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/template/friend79.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 7c2a5647665..a15d1d062c6 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -1319,6 +1319,7 @@ is_specialization_of_friend (tree decl, tree friend_decl)
> of a template class, we want to check if DECL is a specialization
> if this. */
> if (TREE_CODE (friend_decl) == FUNCTION_DECL
> + && DECL_CLASS_SCOPE_P (friend_decl)
> && DECL_TEMPLATE_INFO (friend_decl)
> && !DECL_USE_TEMPLATE (friend_decl))
> {
> diff --git a/gcc/testsuite/g++.dg/template/friend79.C b/gcc/testsuite/g++.dg/template/friend79.C
> new file mode 100644
> index 00000000000..cd2030df019
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/template/friend79.C
> @@ -0,0 +1,20 @@
> +// PR c++/109923
> +
> +template<class T>
> +struct A {
> +private:
> + int x;
> +
> +public:
> + A() : x(0) { }
> +
> + friend void non_templ_friend(A val, A<void> weird) {
> + val.x++; // always works
> + weird.x++; // { dg-error "private" } should only work when T=void
> + }
> +};
> +
> +int main() {
> + non_templ_friend(A<void>(), A<void>()); // { dg-bogus "" }
> + non_templ_friend(A<int>(), A<void>()); // { dg-message "required from here" }
> +}
@@ -1319,6 +1319,7 @@ is_specialization_of_friend (tree decl, tree friend_decl)
of a template class, we want to check if DECL is a specialization
if this. */
if (TREE_CODE (friend_decl) == FUNCTION_DECL
+ && DECL_CLASS_SCOPE_P (friend_decl)
&& DECL_TEMPLATE_INFO (friend_decl)
&& !DECL_USE_TEMPLATE (friend_decl))
{
new file mode 100644
@@ -0,0 +1,20 @@
+// PR c++/109923
+
+template<class T>
+struct A {
+private:
+ int x;
+
+public:
+ A() : x(0) { }
+
+ friend void non_templ_friend(A val, A<void> weird) {
+ val.x++; // always works
+ weird.x++; // { dg-error "private" } should only work when T=void
+ }
+};
+
+int main() {
+ non_templ_friend(A<void>(), A<void>()); // { dg-bogus "" }
+ non_templ_friend(A<int>(), A<void>()); // { dg-message "required from here" }
+}