Re: [PATCH] Fix PR c++/61537

[Adam Butcher <adam at jessamine dot co dot uk>]

	* parser.c (cp_parser_elaborated_type_specifier): Only consider template
	parameter lists outside of function parameter scope.

	* g++.dg/template/pr61537.C: New testcase.
---
 gcc/cp/parser.c                         | 31 ++++++++++++++++++++++---------
 gcc/testsuite/g++.dg/template/pr61537.C | 23 +++++++++++++++++++++++
 2 files changed, 45 insertions(+), 9 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/template/pr61537.C

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 41200a0..c440c99 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -15081,6 +15081,18 @@ cp_parser_elaborated_type_specifier (cp_parser* parser,
 	return cp_parser_make_typename_type (parser, parser->scope,
 					     identifier,
 					     token->location);
+
+      /* Template parameter lists apply only if we are not within a
+	 function parameter list.  */
+      bool template_parm_lists_apply
+	  = parser->num_template_parameter_lists;
+      if (template_parm_lists_apply)
+	for (cp_binding_level *s = current_binding_level;
+	     s && s->kind != sk_template_parms;
+	     s = s->level_chain)
+	  if (s->kind == sk_function_parms)
+	    template_parm_lists_apply = false;
+
       /* Look up a qualified name in the usual way.  */
       if (parser->scope)
 	{
@@ -15123,7 +15135,7 @@ cp_parser_elaborated_type_specifier (cp_parser* parser,
 
 	  decl = (cp_parser_maybe_treat_template_as_class
 		  (decl, /*tag_name_p=*/is_friend
-			 && parser->num_template_parameter_lists));
+			 && template_parm_lists_apply));
 
 	  if (TREE_CODE (decl) != TYPE_DECL)
 	    {
@@ -15136,9 +15148,9 @@ cp_parser_elaborated_type_specifier (cp_parser* parser,
 
 	  if (TREE_CODE (TREE_TYPE (decl)) != TYPENAME_TYPE)
             {
-              bool allow_template = (parser->num_template_parameter_lists
-		                      || DECL_SELF_REFERENCE_P (decl));
-              type = check_elaborated_type_specifier (tag_type, decl, 
+              bool allow_template = (template_parm_lists_apply
+		                     || DECL_SELF_REFERENCE_P (decl));
+              type = check_elaborated_type_specifier (tag_type, decl,
                                                       allow_template);
 
               if (type == error_mark_node)
@@ -15224,15 +15236,16 @@ cp_parser_elaborated_type_specifier (cp_parser* parser,
 	    ts = ts_global;
 
 	  template_p =
-	    (parser->num_template_parameter_lists
+	    (template_parm_lists_apply
 	     && (cp_parser_next_token_starts_class_definition_p (parser)
 		 || cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON)));
 	  /* An unqualified name was used to reference this type, so
 	     there were no qualifying templates.  */
-	  if (!cp_parser_check_template_parameters (parser,
-						    /*num_templates=*/0,
-						    token->location,
-						    /*declarator=*/NULL))
+	  if (template_parm_lists_apply
+	      && !cp_parser_check_template_parameters (parser,
+						       /*num_templates=*/0,
+						       token->location,
+						       /*declarator=*/NULL))
 	    return error_mark_node;
 	  type = xref_tag (tag_type, identifier, ts, template_p);
 	}
diff --git a/gcc/testsuite/g++.dg/template/pr61537.C b/gcc/testsuite/g++.dg/template/pr61537.C
new file mode 100644
index 0000000..12aaf58
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/pr61537.C
@@ -0,0 +1,23 @@
+// PR c++/61537
+// { dg-do compile }
+
+struct A {};
+
+template <typename T>
+struct B
+{
+  template <typename U>
+  void f(U, struct A);
+};
+
+template <typename T>
+template <typename U>
+void B<T>::f(U, struct A)
+{
+}
+
+int main()
+{
+  B<char> b;
+  b.f(42, A());
+}
-- 
2.0.0