From: Jason Merrill <jason@redhat.com>
Date: Wed, 7 Apr 2021 19:38:07 +0000 (-0400)
Subject: c++: base template friend [PR52625]
X-Git-Tag: basepoints/gcc-12~223
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b40d45cb1930e9aa8a1f9a6a8728fd47ebeeaaac;p=thirdparty%2Fgcc.git

c++: base template friend [PR52625]

Here we were mistakenly treating the injected-class-name as a partial
specialization.

gcc/cp/ChangeLog:

	PR c++/52625
	* pt.c (maybe_process_partial_specialization): Check
	DECL_SELF_REFERENCE_P.

gcc/testsuite/ChangeLog:

	PR c++/52625
	* g++.dg/template/friend70.C: New test.
---

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index a08d08d28340..dee802121e5d 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -984,6 +984,10 @@ maybe_process_partial_specialization (tree type)
   if (CLASS_TYPE_P (type) && CLASSTYPE_LAMBDA_EXPR (type))
     return type;
 
+  /* An injected-class-name is not a specialization.  */
+  if (DECL_SELF_REFERENCE_P (TYPE_NAME (type)))
+    return type;
+
   if (TREE_CODE (type) == BOUND_TEMPLATE_TEMPLATE_PARM)
     {
       error ("name of class shadows template template parameter %qD",
diff --git a/gcc/testsuite/g++.dg/template/friend70.C b/gcc/testsuite/g++.dg/template/friend70.C
new file mode 100644
index 000000000000..54965486f795
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/friend70.C
@@ -0,0 +1,9 @@
+// PR c++/52625
+
+template<class>
+class base {};
+
+class derived : public base<derived>
+{
+  template<class> friend class base;
+};