Is there a simple way to load extra packages to ghci when invoked via cabal repl?

cabal repl --ghc-option='-package xyz'

This will load the package you are calling cabal repl from and the package xyz.

To do that after the fact, i.e. when you're already in the REPL and want to load an extra helper module from another package:

GHCi> :set -package xyz
GHCi> :m +XYZ.Module.You.Suddenly.Need

When I needed QuickCheck library in scope of ghci I tried

cabal repl --ghc-option='-package QuickCheck'

and it didn't work at all.

The following saved my day

cabal repl --build-depends "QuickCheck >= 2.14"

This is only tangential. I searched for how to do with stack repl. With Stack you do:

stack repl --package xyz

Here repl is synonymous with ghci.