Doesn't work on spacemacs

[Osager]

I am on Windows 10

haskell-emacs-init seems to run successfully
but when i evaluate (Matrix.identity 3) in the scratch
I get
Debugger entered--Lisp error: (void-function Matrix.identity)

[knupfer]

Hm, how did you install haskell-emacs? No errors occured?
I'm not familiar with spacemacs, but what happens if you evaluate (setq debug-on-error t) and reinstall haskell-emacs?
Have you already tried M-x package-install ?