[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 727f2d4f909f2cdd7207e044bef3477fdb7ff452..e092c4490f55f0254efe17df41ff7baedf591dfd 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 90fb3aee82d4ad94b1109ad4e2ea4c10fde46241..8560e588593397950d6eedafc3e199d58a24864c 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 eddb4576e0fde25fd5af1d60cf5e2b6c66b16f82..1871663415ed9d8093c0be2424bbfff7a13081ce 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;