polysemy-plugin on 8.6 - Polysemy

dep/polysemy/polysemy-plugin/src/Polysemy/Plugin/Fundep/Stuff.hs:10:1-25: error:
    Could not load module ‘FastString’
    It is a member of the hidden package ‘ghc-8.6.5’.
    You can run ‘:set -package ghc’ to expose it.
    (Note: this unloads all the modules in the current scope.)
    Use -v to see a list of the files searched for.
   |
10 | import FastString (fsLit)
   | ^^^^^^^^^^^^^^^^^^^^^^^^^
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