Wow, thanks! I wonder what's causing this...

I've forked the Kata here to add random tests, add a fixed test that tests signum, and some other improvements.

I've forked the Kata [here] to add random tests among other improvements.

I tried to run your solution without {-# LANGUAGE ImportQualifiedPost #-} and tests passed. You also need to change import Data.Traversable qualified as T to import qualified Data.Traversable as T

Still did not fix

Try to add {-# LANGUAGE Haskell2010 #-} and fix compilation errors. It seems the issue is because of lib used to validate imports. It fails if code is not a valid Haskell2010.

I'm having the same trouble as the user below me. My solution is correct and I'm not using any Lens imports but I'm getting the following error:
uncaught exception: IOException of type UserError
user error (Could not parse solution correctly)

I'm also getting this error but i DO have RankNTypes enabled..

Oh, Agda. Didn't realise the kata was available in multiple languages, sorry.

What?

language?

The open Language {{...}} line in the template should be made public so that the tests work.

I see. RankNTypes should be made available for TupleSections to work. The above error will occur when {-# LANGUAGE RankNTypes #-} is missing. Sorry for the stupid question.

How to avoid the following error on the test case Cannot use Control.Lens? I did not import anything that relates to Control.Lens.

uncaught exception: IOException of type UserError
user error (Could not parse solution correctly)

Also known as a difference list. If you're looking for hints, Hughes lists, when run, will not overwrite the list they take as an input.