My ghci version is 8.4.3
I tried
stack install QuickCheck
Something was installed. But when I input import Test.QuickCheck
, it tells Could not find module ‘Test.QuickCheck’
again. How can I fix it?
Firstly, stack install
is not recommended for installing executables or libraries. Instead, there's a couple of things you can do to use the QuickCheck
library:
QuickCheck
in a command such as stack ghci
or stack ghc
, you can add it as a --package
option e.g. to run a REPL to play around with QuickCheck
you can use stack ghci --package QuickCheck
and then write import Test.QuickCheck
.QuickCheck
, then you can run stack ghc --package QuickCheck -- MyProgram.hs
(using the --package
option from the last bullet point). Alternately, you can use stack
's scripting functionality and include a line such as this at the top of your program:
-- stack --resolver lts-12.18 script --package QuickCheck
QuickCheck
in a large project, then add it as a dependency in your my-program.cabal
or project.yaml
file.The same guidance applies to any package you may want to use.