[bison crash] Assertion failure abort with src/muscle-tab.c:323

Hello, this is Ahcheong Lee
I'm currently working on a new fuzzing technique, and I found some crashes
on GNU bison3.5.2.
For ease of maintenance, I'll send one crash by one by email.

There was an assertion failure in src/muscle-tab.c:323
string_decode: Assertion *(value) == '[''
You can reproduce it with the following command:
./bison <attached file>

This is call stack info:
bison: src/muscle-tab.c:323: string_decode: Assertion `*(value) == '[''
failed.

Program received signal SIGABRT, Aborted.
0x00007ffff7a42428 in __GI_raise (sig=sig@entry=6) at
../sysdeps/unix/sysv/linux/raise.c:54
54      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) bt
#0  0x00007ffff7a42428 in __GI_raise (sig=sig@entry=6) at
../sysdeps/unix/sysv/linux/raise.c:54
#1  0x00007ffff7a4402a in __GI_abort () at abort.c:89
#2  0x00007ffff7a3abd7 in __assert_fail_base (fmt=<optimized out>,
assertion=assertion@entry=0x470044 "*(value) == '['",
    file=file@entry=0x470002 "src/muscle-tab.c", line=line@entry=323,
function=function@entry=0x470800 <__PRETTY_FUNCTION__.5179> "string_decode")
    at assert.c:92
#3  0x00007ffff7a3ac82 in __GI___assert_fail (assertion=0x470044 "*(value)
== '['", file=0x470002 "src/muscle-tab.c", line=323,
    function=0x470800 <__PRETTY_FUNCTION__.5179> "string_decode") at
assert.c:101
#4  0x000000000041ab10 in string_decode (key=0x69ec30
"percent_define(lr.default-reduction)") at src/muscle-tab.c:323
#5  0x000000000041dab5 in muscle_percent_define_check_values
(values=0x4738b0 <values+48>) at src/muscle-tab.c:732
#6  0x0000000000436a14 in prepare_percent_define_front_end_variables () at
src/reader.c:750
#7  0x0000000000436982 in reader (gram=0x691bb0 "./bison_assertion_value")
at src/reader.c:719
#8  0x0000000000417e3d in main (argc=2, argv=0x7fffffffe368) at
src/main.c:104


Thank you,
Ahcheong Lee
---------------------------------------------
Ahcheong Lee, Master's student
School of Computing, KAIST
Room# 2438, E3-1, KAIST
373-1 Guseong-dong, Yuseong-gu
Daejeon, South Korea 34141
Phone : 010-7350-3811
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