For emacs users such as myself, a common typo is to use
the emacs "literal next" keystroke (^Q) in the shell,
with default stty(1) settings this is a terminal "start",
to resume from a suspend / "stop" (^S) .
I believe a terminal "start" without any preceding "stop"
should be ignored by the shell, as it is by ksh and
previous bash versions (eg. bash-3.2.39 ).

However, now with :
  GNU bash, version 4.0.35(3)-release (x86_64-unknown-linux-gnu)

inadvertently using the "^Q" keystroke when preceded by an escape "\\" character causes bash heap corruption and to crash,
as shown by this "gdb" session :

$ gdb ./bash
...
This GDB was configured as "x86_64-gnu-linux".
...
(gdb) start -i -
Temporary breakpoint 1 at 0x41c720: file ../shell.c, line 349.
Starting program: /usr/src/bash-4.0/x86_64/bash -i -

Temporary breakpoint 1, main (argc=3, argv=0x7fffffffecb8, env=0x7fffffffecd8) at ../shell.c:349
349     {
(gdb) c
Continuing.
[ root@jvdspc:/usr/src/bash-4.0/x86_64 18:29:35 501:1 ]
$ echo '\ \
#          ^-- here I had keyed '^Q<TAB>'
#     (when I should have keyed '^V<TAB>' ! )
# but this should not happen! :
malloc: unknown:0: assertion botched
free: start and end chunk sizes differ
last command: . ~/clean.env
Aborting...
Program received signal SIGABRT, Aborted.
0x00007ffff78b419e in *__GI_raise (sig=<value optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:67
67        int res = INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);
(gdb) where
#0  0x00007ffff78b419e in *__GI_raise (sig=<value optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:67
#1  0x00007ffff78b5610 in *__GI_abort () at abort.c:92
#2  0x0000000000439244 in programming_error (format=0x7097e8 ". ~/clean.env") at ../error.c:175
#3  0x00000000004a18a1 in internal_free (mem=0x6e15e8, file=0x0, line=0, flags=<value optimized out>) at ../../../lib/malloc/malloc.c:902
#4  0x0000000000486f91 in rl_filename_completion_function (text=<value optimized out>, state=21877) at ../../../lib/readline/complete.c:2137
#5  0x00000000004875f3 in rl_completion_matches (text=0x6e15c8 "\\ \\", entry_function=<value optimized out>) at ../../../lib/readline/complete.c:1887
#6  0x0000000000488978 in rl_complete_internal (what_to_do=9) at ../../../lib/readline/complete.c:1746
#7  0x0000000000480c4b in _rl_dispatch_subseq (key=9, map=0x6d42a0, got_subseq=0) at ../../../lib/readline/readline.c:769
#8  0x00000000004813b7 in readline_internal_char () at ../../../lib/readline/readline.c:548
#9  0x00000000004817ad in readline_internal_charloop (prompt=<value optimized out>) at ../../../lib/readline/readline.c:575
#10 readline_internal (prompt=<value optimized out>) at ../../../lib/readline/readline.c:589
#11 readline (prompt=<value optimized out>) at ../../../lib/readline/readline.c:338
#12 0x00000000004208a7 in yy_readline_get () at ../parse.y:1314
#13 0x000000000041fcde in yy_getc (remove_quoted_newline=1) at ../parse.y:1247
#14 shell_getc (remove_quoted_newline=1) at ../parse.y:2096
#15 0x0000000000422dca in read_token (command=<value optimized out>) at ../parse.y:2730
#16 0x0000000000425c1e in yylex () at ../parse.y:2362
#17 yyparse () at y.tab.c:2010
#18 0x000000000041dbaa in parse_command () at ../eval.c:228
#19 0x000000000041dc76 in read_command () at ../eval.c:272
#20 0x000000000041deb4 in reader_loop () at ../eval.c:137
#21 0x000000000041d5d3 in main (argc=<value optimized out>, argv=<value optimized out>, env=<value optimized out>) at ../shell.c:741
(gdb)