As noted in GHC Trac #13258, mono-traversable currently fails to build with GHC 8.2. This is because the validity checking for default type signatures tightened up in GHC 8.2 (see also GHC Trac #12918). In particular, GHC requires that the default type signature of a method must be the same as the non-default type signature, modulo constraints.
This PR fixes the default type signatures in Data.MonoTraversable to meet this criterion.
snoyberg
commented
7 years ago
As noted in GHC Trac #13258,
mono-traversablecurrently fails to build with GHC 8.2. This is because the validity checking for default type signatures tightened up in GHC 8.2 (see also GHC Trac #12918). In particular, GHC requires that the default type signature of a method must be the same as the non-default type signature, modulo constraints.This PR fixes the default type signatures in
Data.MonoTraversableto meet this criterion.