match_co: needs more cases

I made some strictifying changes and started getting this msg from ghc: match_co: needs more cases vector-0.10.0.1:Data.Vector.Generic.Mutable.MVector{tc r46} (Sym <(vector-0.10.0.1:Data.Vector.TFCo:R:MutableVector{tc r45})>) It's not just TimeVectorStorable.Sample (which is indeed stored in Data.Vectors), we also have some mysterious compiler-generated symbols: match_co: needs more cases vector-0.10.0.1:Data.Vector.Generic.Mutable.MVector{tc rQA} (Sym <(vector-0.10.0.1:Data.Vector.TFCo:R:MutableVector{tc rQz})>) I assume this is harmless, but I didn't see any other references to this error on the web or on the ghc trac so maybe it's new?