[PR c++/85634] Fix tsubst ICE

https://gcc.gnu.org/ml/gcc-patches/2018-06/msg01274.html
	PR c++/85634
	* friend.c (add_friend): Keep lookup sets of tempate sets.

	PR c++/85634
	* g++.dg/lookup/pr85634-2.C: New.

From-SVN: r261817

gcc/cp/ChangeLog

+2018-06-20  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/85634
+	* friend.c (add_friend): Keep lookup sets of tempate sets.
+
 2018-06-20  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* decl.c (grokfndecl): Add const cp_decl_specifier_seq* parameter;

gcc/cp/friend.c

@@ -173,6 +173,12 @@ add_friend (tree type, tree decl, bool complain)
   if (decl == error_mark_node)
     return;
 
+  if (TREE_CODE (decl) == FUNCTION_DECL
+      && DECL_TEMPLATE_INSTANTIATION (decl))
+    /* We'll have parsed this as a declaration, and therefore not
+       marked the lookup set for keeping.  Do that now.  */
+    lookup_keep (DECL_TI_TEMPLATE (decl));
+
   typedecl = TYPE_MAIN_DECL (type);
   list = DECL_FRIENDLIST (typedecl);
   name = DECL_NAME (decl);

gcc/testsuite/ChangeLog

+2018-06-20  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/85634
+	* g++.dg/lookup/pr85634-2.C: New.
+
 2018-06-20  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* g++.dg/template/friend65.C: New.

gcc/testsuite/g++.dg/lookup/pr85634-2.C

+// PR c++/85634
+
+namespace bsl {
+  template <class T> void frob (const T *);
+}
+
+using namespace bsl;
+
+template<class VALUE> void frob (const VALUE &);
+
+template <typename T>
+struct TPL {
+  friend void frob <T> (const T &);
+};
+
+TPL<int> x;