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C++ PATCH for c++/71227 (error specializing friend)
- From: Jason Merrill <jason at redhat dot com>
- To: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 31 May 2016 11:38:19 -0400
- Subject: C++ PATCH for c++/71227 (error specializing friend)
- Authentication-results: sourceware.org; auth=none
My fix for 70522 caused us to reject this testcase as well. I think
that this is correct; I don't see any reason why lookup to find a
template to specialize should be treated differently from other normal
lookup. But we could be more helpful in the diagnostic, especially
since this breaks previously working code.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit fa370e284e8b04f85fb626b20919f52ef542748f
Author: Jason Merrill <jason@redhat.com>
Date: Wed May 25 16:10:24 2016 -0400
PR c++/71227
* pt.c (check_explicit_specialization): Give better diagnostic about
specializing a hidden friend.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index df3d634..a57da62 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -2807,12 +2807,22 @@ check_explicit_specialization (tree declarator,
/* Find the namespace binding, using the declaration
context. */
fns = lookup_qualified_name (CP_DECL_CONTEXT (decl), dname,
- false, true);
+ /*type*/false, /*complain*/true,
+ /*hidden*/true);
if (fns == error_mark_node || !is_overloaded_fn (fns))
{
error ("%qD is not a template function", dname);
fns = error_mark_node;
}
+ else if (remove_hidden_names (fns) == NULL_TREE)
+ {
+ tree fn = get_first_fn (fns);
+ if (pedwarn (DECL_SOURCE_LOCATION (decl), 0,
+ "friend declaration %qD is not visible to "
+ "explicit specialization", fn))
+ inform (DECL_SOURCE_LOCATION (fn),
+ "friend declaration here");
+ }
}
declarator = lookup_template_function (fns, NULL_TREE);
diff --git a/gcc/testsuite/g++.dg/template/friend62.C b/gcc/testsuite/g++.dg/template/friend62.C
new file mode 100644
index 0000000..c9796c4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/friend62.C
@@ -0,0 +1,16 @@
+// PR c++/71227
+// { dg-options "" }
+
+class A {
+ public:
+ template<typename T>
+ friend int f(int x, T v) { // { dg-message "declaration" }
+ return x + v;
+ }
+};
+
+
+template<>
+int f(int x, int v) { // { dg-warning "friend" }
+ return x + v;
+}