I would like to use the [asdf-haskell](https://github.com/vic/asdf-haskell) tool. I have installed [asdf-vm](https://github.com/asdf-vm/asdf), and I have installed `asdf-haskell`.

I have installed `ghc-8.4.3` and `ghc-8.6.5` by running `asdf install haskell 8.4.3` and `asdf install haskell 8.6.5`. The installs seemed to have worked, at least on the "asdf side". The contents of my directory `~/.asdf/installs/haskell` are as expected

However, when I am in a stack project, and I run `stack test`, stack goes ahead and downloads `ghc-8.6.5` again into the `~/.stack`. I was expecting it to use what was already downloaded to the `~/.asdf` directory. What am I doing wrong here?