segfault w/ localvar_inherit and associative array insert

[Grisha Levit]

shopt -s localvar_inherit
declare -A var
f() { declare var+=([0]=X); }; f

Segmentation fault: 11

* thread #1, stop reason = signal SIGSTOP
  * frame #0: 0x0000000107abb72f bash`hash_search + 47
    frame #1: 0x0000000107ac7324 bash`assoc_insert + 36
    frame #2: 0x0000000107ac6658 bash`assign_compound_array_list + 200
    frame #3: 0x0000000107aaac32 bash`do_assignment_internal + 1042
    frame #4: 0x0000000107ab2384 bash`expand_word_list_internal + 1348
    frame #5: 0x0000000107a87f41 bash`execute_command_internal + 10801
    frame #6: 0x0000000107a854a9 bash`execute_command + 137
    frame #7: 0x0000000107a86a14 bash`execute_command_internal + 5380
    frame #8: 0x0000000107a87043 bash`execute_command_internal + 6963
    frame #9: 0x0000000107a8ad2c bash`execute_function + 1628
    frame #10: 0x0000000107a88b38 bash`execute_command_internal + 13864
    frame #11: 0x0000000107a86a60 bash`execute_command_internal + 5456
    frame #12: 0x0000000107adfa1d bash`parse_and_execute + 877
    frame #13: 0x0000000107a70713 bash`run_one_command + 163
    frame #14: 0x0000000107a6f765 bash`main + 5301
    frame #15: 0x00007fff5d381015 libdyld.dylib`start + 1
    frame #16: 0x00007fff5d381015 libdyld.dylib`start + 1