[Bug libstdc++/95223] New: [11 regression] hash table checking failed: equal operator returns true for a pair of values with a different hash value

[dimhen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95223

            Bug ID: 95223
           Summary: [11 regression] hash table checking failed: equal
                    operator returns true for a pair of values with a
                    different hash value
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dimhen at gmail dot com
  Target Milestone: ---

r11-459 PASS
r11-495 FAIL

$ cat x.cpp
struct s { } a;
struct b;
#include <cstdarg>
#include <map>

$ g++ -std=c++98 x.cpp
hash table checking failed: equal operator returns true for a pair of values
with a different hash value
In file included from
/home/dimhen/arch-gcc/gcc_current/include/c++/11.0.0/map:60,
                 from x.cpp:4:
/home/dimhen/arch-gcc/gcc_current/include/c++/11.0.0/bits/stl_tree.h:2149:37:
internal compiler error: in hashtab_chk_error, at hash-table.c:137
 2149 |     _M_insert_unique(const _Val& __v)
      |                                     ^
0xab76f2 hashtab_chk_error()
        /home/dimhen/src/gcc_current/gcc/hash-table.c:137
0xc7b73d hash_table<spec_hasher, false, xcallocator>::verify(spec_entry*
const&, unsigned int)
        /home/dimhen/src/gcc_current/gcc/hash-table.h:1033
0xc7b889 hash_table<spec_hasher, false,
xcallocator>::find_with_hash(spec_entry* const&, unsigned int)
        /home/dimhen/src/gcc_current/gcc/hash-table.h:934
0xc62f0d lookup_template_class_1
        /home/dimhen/src/gcc_current/gcc/cp/pt.c:9776
0xc65213 lookup_template_class(tree_node*, tree_node*, tree_node*, tree_node*,
int, int)
        /home/dimhen/src/gcc_current/gcc/cp/pt.c:10115
0xc65213 tsubst_aggr_type
        /home/dimhen/src/gcc_current/gcc/cp/pt.c:13369
0xc5f7f1 maybe_update_decl_type(tree_node*, tree_node*)
        /home/dimhen/src/gcc_current/gcc/cp/pt.c:4858
0xc18263 cp_parser_init_declarator
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:20595
0xc1f8d4 cp_parser_single_declaration
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:29490
0xc1fa4b cp_parser_template_declaration_after_parameters
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:29062
0xc201a0 cp_parser_explicit_template_declaration
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:29328
0xc231e9 cp_parser_declaration
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:13388
0xc22dd2 cp_parser_toplevel_declaration
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:13467
0xc22dd2 cp_parser_declaration_seq_opt
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:13315
0xc22dd2 cp_parser_namespace_body
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:19723
0xc22dd2 cp_parser_namespace_definition
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:19701
0xc231d8 cp_parser_declaration
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:13419
0xc2381a cp_parser_translation_unit
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:4725
0xc2381a c_parse_file()
        /home/dimhen/src/gcc_current/gcc/cp/parser.c:43976
0xd384ab c_common_parse_file()
        /home/dimhen/src/gcc_current/gcc/c-family/c-opts.c:1190
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.