I'm on nixos and due to stack's integration with Nix/Nixos the following command is very slow:

```
time stack ghc
ghc: no input files
Usage: For basic information, try the `--help' option.
stack ghc  1.14s user 0.13s system 95% cpu 1.324 total

```

This means after a few keystrokes the emacs editor hangs... So I usually uninstall stack to remove it from the `$PATH`.

How can I disable this, to avoid this really frustrating delay?

In the messages:

```
haskell-stack-ghc: Flycheck checker haskell-stack-ghc returned non-zero exit code 1,

```

I have tried adding:

```
(add-to-list '(flycheck-disabled-checkers '(haskell-stack-ghc)))

```

to my init file, but there was no change in behavior.