[PR86747] tsubst friend tpl ctxt before looking it up for dupes

When a member template is redeclared as a friend, we enter the context
of the member before looking it up, and then we check that the decls
are compatible.  However, when the member template references template
types of the enclosing context, say an enclosing template class, the
compare fails because the friend decl is already tsubsted, whereas the
looked up name isn't.

The problem is that the enclosing context is taken from the friend
declaration before tsubsting it, so we look up in the context of the
generic template instead of that of the tsubsted one we're
specializing.  The solution is to tsubst the enclosing context when
it's a non-namespace scope.

for  gcc/cp/ChangeLog

	PR c++/86747
	* pt.c (tsubst_friend_class): Enter tsubsted class context.

for  gcc/testsuite/ChangeLog

	PR c++/86747
	* g++.dg/pr86747.C: New.

From-SVN: r266875

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 727f2d4..e092c44 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,8 @@
 2018-12-06  Alexandre Oliva <aoliva@redhat.com>
 
+       PR c++/86747
+       * pt.c (tsubst_friend_class): Enter tsubsted class context.
+
        PR c++/86397
        * except.c (build_noexcept_spec): Resolve nondependent
        expressions.

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 90fb3ae..8560e58 100644 (file)
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -10558,7 +10558,10 @@ tsubst_friend_class (tree friend_tmpl, tree args)
   if (TREE_CODE (context) == NAMESPACE_DECL)
     push_nested_namespace (context);
   else
-    push_nested_class (context);
+    {
+      context = tsubst (context, args, tf_error, NULL_TREE);
+      push_nested_class (context);
+    }
 
   tmpl = lookup_name_real (DECL_NAME (friend_tmpl), /*prefer_type=*/false,
                           /*non_class=*/false, /*block_p=*/false,

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index eddb457..1871663 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2018-12-06  Alexandre Oliva <aoliva@redhat.com>
 
+       PR c++/86747
+       * g++.dg/pr86747.C: New.
+
        PR c++/86397
        * g++.dg/cpp0x/pr86397-1.C: New.
        * g++.dg/cpp0x/pr86397-2.C: New.

diff --git a/gcc/testsuite/g++.dg/pr86747.C b/gcc/testsuite/g++.dg/pr86747.C
new file mode 100644 (file)
index 0000000..5b0a0bb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr86747.C
@@ -0,0 +1,8 @@
+// { dg-do compile }
+
+template <typename T> class A {
+  template <void (A::*p)()> class C; // #1
+  template <void (A::*q)()> friend class C; // #2
+};
+
+A<double> a;