[Bug c++/93869] [10 Regression] ICE in contains_struct_check with -Wmismatched-tags upon redundant typename

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93869

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
This patch https://gcc.gnu.org/ml/gcc-patches/2020-02/msg01183.html does not
fix it.  I think the fix is to check class_key earlier in the function:

--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -30987,6 +30987,13 @@ cp_parser_check_class_key (cp_parser *parser,
location_t key_loc,
   if (!warn_mismatched_tags && !warn_redundant_tags)
     return;

+  /* Only consider the true class-keys below and ignore typename_type,
+     etc. that are not C++ class-keys.  */
+  if (class_key != class_type
+      && class_key != record_type
+      && class_key != union_type)
+    return;
+
   tree type_decl = TYPE_MAIN_DECL (type);
   tree name = DECL_NAME (type_decl);
   /* Look up the NAME to see if it unambiguously refers to the TYPE
@@ -30995,13 +31002,6 @@ cp_parser_check_class_key (cp_parser *parser,
location_t key_loc,
   tree decl = cp_parser_lookup_name_simple (parser, name, input_location);
   pop_deferring_access_checks ();

-  /* Only consider the true class-keys below and ignore typename_type,
-     etc. that are not C++ class-keys.  */
-  if (class_key != class_type
-      && class_key != record_type
-      && class_key != union_type)
-    return;
-
   /* The class-key is redundant for uses of the CLASS_TYPE that are
      neither definitions of it nor declarations, and for which name
      lookup returns just the type itself.  */


Martin, do you want me to post it?  (I can wait until your patch above is
committed if you don't want any conflicts.)