coerce package:capability

Coerce the type in the context m to to. Example:

newtype MyInt = MyInt Int
newtype MyReader a = MyReader (Reader Int a)
deriving (HasReader "a" MyInt) via
Coerce MyInt (MonadReader (Reader Int))

Converts the HasReader "a" Int instance of MonadReader (Reader Int) to a HasReader "a" MyInt instance using Coercible Int MyInt.