Hello, I am looking at this task https://ghc.haskell.org/trac/ghc/ticket/10789 https://ghc.haskell.org/trac/ghc/ticket/10789 and need some help on implementing it. With the help of @int_index I found the place in TcErrors.hs where the error printing occurs and I think the check that I need to add will look similar to this one https://github.com/ghc/ghc/blob/master/compiler/typecheck/TcErrors.hs#L1935 https://github.com/ghc/ghc/blob/master/compiler/typecheck/TcErrors.hs#L1935. So I guess that we need to check if one of the kinds of two types we are comparing defaults to * (or Type if you will) and then add new warning that will be more descriptive as to why the failure happened. Maybe there is a way to check if what we are comparing are actually type families so that would make the job easier I guess. Richard Eisenberg offered some help on this but I am not sure how to grab hold of him so I'd appreciate any help I could get. Thanks, Sasa