Started with r8 before 20180525 :


$ cat z1.cc
struct {
  struct {
    operator int ();
    int a;
  };
  operator int;
};


$ g++-11-20201122 -c z1.cc
z1.cc:6:12: internal compiler error: tree check: expected overload, have function_decl in get_class_binding_direct, at cp/name-lookup.c:1332
    6 |   operator int
      |            ^~~
0x6520ba tree_check_failed(tree_node const*, char const*, int, char const*, ...)
        ../../gcc/tree.c:9810
0x7fad5a tree_check(tree_node*, char const*, int, char const*, tree_code)
        ../../gcc/tree.h:3317
0x7fad5a get_class_binding_direct(tree_node*, tree_node*, bool)
        ../../gcc/cp/name-lookup.c:1332
0x8ea66b lookup_field_r
        ../../gcc/cp/search.c:978
0x8e904e dfs_walk_all(tree_node*, tree_node* (*)(tree_node*, void*), tree_node* (*)(tree_node*, void*), void*)
        ../../gcc/cp/search.c:1408
0x8e91fc lookup_member(tree_node*, tree_node*, int, bool, int, access_failure_info*)
        ../../gcc/cp/search.c:1121
0x8e95a0 lookup_fnfields(tree_node*, tree_node*, int, int)
        ../../gcc/cp/search.c:1327
0x80aada lookup_name_1
        ../../gcc/cp/name-lookup.c:6587
0x80aada lookup_name(tree_node*, LOOK_where, LOOK_want)
        ../../gcc/cp/name-lookup.c:6665
0x811255 lookup_name(tree_node*, LOOK_want)
        ../../gcc/cp/name-lookup.h:294
0x811255 cp_parser_lookup_name
        ../../gcc/cp/parser.c:28864
0x818615 cp_parser_diagnose_invalid_type_name
        ../../gcc/cp/parser.c:3365
0x84a063 cp_parser_parse_and_diagnose_invalid_type_name
        ../../gcc/cp/parser.c:3619
0x860367 cp_parser_member_declaration
        ../../gcc/cp/parser.c:25456
0x82f722 cp_parser_member_specification_opt
        ../../gcc/cp/parser.c:25306
0x82f722 cp_parser_class_specifier_1
        ../../gcc/cp/parser.c:24395
0x832159 cp_parser_class_specifier
        ../../gcc/cp/parser.c:24706
0x832159 cp_parser_type_specifier
        ../../gcc/cp/parser.c:17962
0x832d86 cp_parser_decl_specifier_seq
        ../../gcc/cp/parser.c:14584
0x8339f1 cp_parser_simple_declaration
        ../../gcc/cp/parser.c:13841