HSCOLOUR is a basic option for all Haskell ports. But it is also an option for hs-hscolour itself which leads to a dependency loop (depends directly on itself) when building or upgrading hs-hscolour.
HSCOLOUR should be excluded from this port configuration. It results in annoyances, when it is set accidently set (or globally in /etc/make.conf).
That might be easily the case. We have fought with this one a lot back in the past, so I will need some time to think it over again.
Created attachment 167289 [details]
A proposed fix for the problem
I have created a patch for fixing this problem. It also makes it possible to have colorized documentation for HsColour itself, so the option does not have to excluded for that port (as it was done before).
Please, try it and get back on the results.
HSCOLOUR is gone now, so the problem should be solved.