http://pubs.opengroup.org/onlinepubs/9699919799/utilities/sh.html
says:
If the shell is interactive:
SIGQUIT and SIGTERM signals shall be ignored.
If I type "foo", then Ctrl-\, then "bar", I get:
$ foo^\
$ bar
posh: bar: not found
which is wrong.
If I type "foo", then send a SIGQUIT or a SIGTERM with a "kill -QUIT"
or "kill -TERM" from another shell, then type "bar", I get:
$ foo
$ bar
posh: foobar: not found
The behavior is now OK except that a new prompt should not be
displayed when the SIGQUIT/SIGTERM signal is received.