f-string string_parser.c regression: Assertion *str < end failed #93418

./python -c 'f"{i="'

(gdb) run -c 'f"{i="'
... the usual ...
python: ../gpshead/Parser/string_parser.c:806: fstring_find_expr: Assertion `*str < end' failed.

Program received signal SIGABRT, Aborted.
__GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:49
49      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) bt
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:49
#1  0x00007ffff7c86546 in __GI_abort () at abort.c:79
#2  0x00007ffff7c8642f in __assert_fail_base (fmt=0x7ffff7dfcdf8 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", 
    assertion=0x55555590ca64 "*str < end", file=0x55555590c3d0 "../gpshead/Parser/string_parser.c", line=806, function=<optimized out>)
    at assert.c:92
#3  0x00007ffff7c95222 in __GI___assert_fail (assertion=assertion@entry=0x55555590ca64 "*str < end", 
    file=file@entry=0x55555590c3d0 "../gpshead/Parser/string_parser.c", line=line@entry=806, 
    function=function@entry=0x55555590cc30 <__PRETTY_FUNCTION__.6> "fstring_find_expr") at assert.c:101
#4  0x00005555556af7f2 in fstring_find_expr (p=p@entry=0x7ffff7761840, str=str@entry=0x7fffffffcfe0, end=end@entry=0x7ffff773cd25 "\"", 
    raw=raw@entry=0, recurse_lvl=recurse_lvl@entry=0, expr_text=expr_text@entry=0x7fffffffcf50, expression=0x7fffffffcf58, 
    first_token=0x7ffff773ad40, t=0x7ffff773ad40, last_token=0x7ffff773ad40) at ../gpshead/Parser/string_parser.c:783
#5  0x00005555556af92e in fstring_find_literal_and_expr (p=p@entry=0x7ffff7761840, str=str@entry=0x7fffffffcfe0, 
    end=end@entry=0x7ffff773cd25 "\"", raw=raw@entry=0, recurse_lvl=recurse_lvl@entry=0, literal=literal@entry=0x7fffffffcf48, 
    expr_text=0x7fffffffcf50, expression=0x7fffffffcf58, first_token=0x7ffff773ad40, t=0x7ffff773ad40, last_token=0x7ffff773ad40)
    at ../gpshead/Parser/string_parser.c:917
#6  0x00005555556afb17 in _PyPegen_FstringParser_ConcatFstring (p=p@entry=0x7ffff7761840, state=state@entry=0x7fffffffcff0, 
    str=str@entry=0x7fffffffcfe0, end=0x7ffff773cd25 "\"", raw=0, recurse_lvl=recurse_lvl@entry=0, first_token=0x7ffff773ad40, t=0x7ffff773ad40, 
    last_token=0x7ffff773ad40) at ../gpshead/Parser/string_parser.c:1142
#7  0x00005555556480dd in _PyPegen_concatenate_strings (p=p@entry=0x7ffff7761840, strings=strings@entry=0x555555c43560)
    at ../gpshead/Parser/action_helpers.c:911
#8  0x0000555555652607 in strings_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:15467
#9  0x0000555555661df1 in atom_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:14273
#10 0x000055555567ac83 in t_primary_raw (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:18112
#11 0x000055555567afdf in t_primary_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:17902
#12 0x000055555567f196 in single_subscript_attribute_target_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:17791
#13 0x000055555567fbb0 in _tmp_12_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:24111
#14 0x0000555555699f99 in assignment_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:2241
#15 0x000055555569af35 in simple_stmt_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:1648
#16 0x000055555569c67e in simple_stmts_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:1543
#17 0x00005555556a2bfe in statement_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:1366
#18 0x00005555556a2e61 in _loop1_3_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:23542
#19 0x00005555556a3040 in statements_rule (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:1298
#20 0x00005555556aa782 in file_rule (p=0x7ffff7761840) at ../gpshead/Parser/parser.c:1057
#21 0x00005555556ad811 in _PyPegen_parse (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/parser.c:38559
#22 0x0000555555645162 in _PyPegen_run_parser (p=p@entry=0x7ffff7761840) at ../gpshead/Parser/pegen.c:817
#23 0x0000555555645445 in _PyPegen_run_parser_from_string (str=str@entry=0x7ffff788f8a0 "f\"{i=\"\n", start_rule=start_rule@entry=257, 
    filename_ob=filename_ob@entry='<string>', flags=flags@entry=0x7fffffffd628, arena=arena@entry=0x7ffff7787940)
    at ../gpshead/Parser/pegen.c:932
#24 0x00005555556afc7c in _PyParser_ASTFromString (str=str@entry=0x7ffff788f8a0 "f\"{i=\"\n", filename='<string>', mode=mode@entry=257, 
    flags=flags@entry=0x7fffffffd628, arena=arena@entry=0x7ffff7787940) at ../gpshead/Parser/peg_api.c:14
#25 0x000055555584fa0e in PyRun_StringFlags (str=str@entry=0x7ffff788f8a0 "f\"{i=\"\n", start=start@entry=257, 
    globals={'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <type at remote 0x555555bde730>, '__spec__': None, '__annotations__': {}, '__builtins__': <module at remote 0x7ffff7907350>}, 
    locals={'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <type at remote 0x555555bde730>, '__spec__': None, '__annotations__': {}, '__builtins__': <module at remote 0x7ffff7907350>}, flags=flags@entry=0x7fffffffd628) at ../gpshead/Python/pythonrun.c:1600
#26 0x000055555584fa8e in PyRun_SimpleStringFlags (command=0x7ffff788f8a0 "f\"{i=\"\n", flags=flags@entry=0x7fffffffd628)
    at ../gpshead/Python/pythonrun.c:486
#27 0x00005555558705a7 in pymain_run_command (command=<optimized out>) at ../gpshead/Modules/main.c:255

f'{i=}{i=}{i=}{i=}{i:m{i=}{i=}{i=}{i=}{h=}{i=}i{i=}{i=}{i=}{i=}{i=}{i=}{i=}{i=}{i=}{i:}{y5}{i=}{i=}{i=}{i='/{''x\ިr]\r\srr@\n\]\]\25}=}{i=}{i:}{i=}{i=}{i=}{E=XXXE,bqE=XX,E=bE,bqE}{i=}{i=}{i=}{}{i=}{i=}{i=}{i5}as{i=}Bi=}{i=}{i=}{i=}{i=}{i=}{i=}{i}}y}}}}}}}}}}}}}}6r\r\n\rrr\]srr@\n\r\]'\r\srr\]\r\r@\n\Y\r\.2n\]\r\r'\n\\r\n\r\]\r\srr@\n\]\]128r\r\n\rrr\]srr@\n\r\]\r\srr@\n\]\r\rx\ިr\srr@\n\r\]\r\srr@\n\]\r\n\]\r\r@\n\\r\n\r\]\r\srr@\n\]\]\0r\r\n\rrr\]srr@\n\r\]\r\srr@\n\]\r\rx\ިr\srr@\n\r\]\\r\]\r\srr@\n\]\r\\ddddddddddddddd\r\]\r\srr@\n\]\dddddddddddddddddd]\2r\]\r\r\~'