+ hsSigsFVs sigs `plusFV`
+ dm_fvs
+ where
+ dm_fvs = case maybe_meths of
+ Nothing -> mkFVs [v | ClassOpSig _ (DefMeth v) _ _ <- sigs]
+ -- No method bindings, so this class decl comes from an interface file,
+ -- So we want to treat the default-method names as free (they should
+ -- be defined somewhere else). [In source code this is not so; the class
+ -- decl will bind whatever default-methods are necessary.]
+ Just _ -> emptyFVs -- Source code, so the default methods
+ -- are *bound* not *free*