The following works:

$ stack new foo
$ cd foo
$ stack exec bash

However, the following does not:

$ stack exec -- bash
/nix/store/gb2dwphbdjk56h0lbbyma32rlid022ad-bash-4.3-p42/bin/bash: --extra-lib-dirs=/nix/store/gf16fp2wxbfq0c6r7j6386gkk4r3aqdr-apache-maven-3.3.3/lib : option non valable

The problem seems to be that if you use -- to delimit arguments passed to the subcommand, Stack for some reason passes extra arguments to the subcommand, which it of course fails to recognize. Without -- this seems to work fine.