Command line argument is being converted to bytes for some reason

I'm on Windows (sadly)

And the latest haskell-mode seems broken. The command-line argument `--ghc-option=-ferror-spans` when starting up a new 'cabal-repl' process is being converted to byte code for some reason.

Stepping through the debugger, it seems the error is introduced when `haskell-process-compute-process-log-and-command` in haskell-process.el returns:

`( "cabal" "repl" 45 45 103 104 99 45 111 112 116 105 111 110 61 45 102 101 114 114 111 114 45 115 112 97 110 115)`

This then leads to emacs to report:

`Wrong type argument: stringp, 45`

when attempting to load a file.

No idea why this is happening.