I setted `haskell-process-type` to 'ghci.
I evaluated a simple haskell src block, but it reports I need have a `*haskell*` inferior. Then I executed command [M-x run-haskell].
Then I get error:

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  expand-file-name(nil)
  locate-dominating-file(nil "cabal.sandbox.config")
  haskell-process-type()
  haskell-program-name-with-args()
  inferior-haskell-start-process()
  inferior-haskell-process()
  run-haskell()
  funcall-interactively(run-haskell)
  call-interactively(run-haskell record nil)
  command-execute(run-haskell record)
  #f(compiled-function (cmd) #<bytecode 0x244f2f9>)("run-haskell")
  ivy-call()
  ivy-read("M-x " [special-lispy-clone
  ....
  counsel-M-x()
  funcall-interactively(counsel-M-x)
  call-interactively(counsel-M-x nil nil)
  command-execute(counsel-M-x)

[stardiviner]           <Hack this world!>      GPG key ID: 47C32433
IRC(freeenode): stardiviner                     Twitter:  @numbchild
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Blog: http://stardiviner.github.io/

On Wed, Nov 15, 2017 at 11:35 PM, Nick Dokos <ndokos@gmail.com> wrote:
"numbchild@gmail.com" <numbchild@gmail.com> writes:

> I checked out your answer, I have meet all your said requirements. GHCi, inf-haskell (after I installed package haskell-mode) and setting `haskell-program-name`, I found there is no
> `defcustom` variable option named `haskell-program-name` at all.

You probably need to set haskell-process-type to ghci. If that works, please let me know and I'll update the answer on SO.

>
> [stardiviner]           <Hack this world!>      GPG key ID: 47C32433
> IRC(freeenode): stardiviner                     Twitter:  @numbchild
> Key fingerprint = 9BAA 92BC CDDD B9EF 3B36  CB99 B8C4 B8E5 47C3 2433
> Blog: http://stardiviner.github.io/
>
> On Wed, Nov 15, 2017 at 9:17 PM, numbchild@gmail.com <numbchild@gmail.com> wrote:
>
>     I required `(require 'inf-haskell)` But have not found the command `inf-haskell` to start inferior process.
>
>     [stardiviner]           <Hack this world!>      GPG key ID: 47C32433
>     IRC(freeenode): stardiviner                     Twitter:  @numbchild
>     Key fingerprint = 9BAA 92BC CDDD B9EF 3B36  CB99 B8C4 B8E5 47C3 2433
>     Blog: http://stardiviner.github.io/
>
>     On Mon, Nov 13, 2017 at 11:43 PM, Nick Dokos <ndokos@gmail.com> wrote:
>
>         stardiviner <numbchild@gmail.com> writes:
>
>         > When I execute the following Haskell src block:
>         >
>         > ```
>         >
>         > #+BEGIN_SRC haskell :session :tangle "Data/Code/hello_world.hs"
>         > main :: IO ()
>         > main = do
>         >   putStrLn "Hello, World!"
>         > #+END_SRC
>         >
>         > ```
>         >
>         > It reports error:
>         >
>         > ```
>         >
>         > Debugger entered--Lisp error: (file-missing "Cannot open load file" "No
>         > such file or directory" "inf-haskell")
>         >   require(inf-haskell)
>
>         See my answer to this SO question:
>
>           https://stackoverflow.com/questions/42081379/how-to-set-up-org-babel-for-haskell-with-stack
>
>         for some details on setting up the environment.
>
>         --
>         Nick
>

--
Nick