lookupInstEnv: "#ifdef DEBUG"-protect trace code
that got included in prev. commit.
(I'm guessing it either should be removed or moved
into the ASSERT, but I'll let the original committer
decide which).
Nothing -> find rest
Just _ -> NoMatch (any_match rest)
Just (subst, leftovers) -> ASSERT( null leftovers )
+#ifdef DEBUG
pprTrace "lookupInst" (vcat [text "look:" <+> ppr key_cls <+> ppr key_tys,
text "found:" <+> ppr dfun_id,
text "env:" <+> ppr (classInstEnv env key_cls)]) $
+#endif
FoundInst subst dfun_id
any_match rest = or [ maybeToBool (matchTys tvs tpl key_tys)