It's possible that returning Nothing was the right thing to do here,
but the comment and variable name indicated that it was written for
implicit parameters, so make it a panic for now just in case.
-lookupPred ip_pred = return Nothing -- Implicit parameters
+lookupPred (IParam {}) = return Nothing -- Implicit parameters
+lookupPred (EqPred {}) = panic "lookupPred EqPred"
record_dfun_usage dfun_id
= do { hsc_env <- getTopEnv
record_dfun_usage dfun_id
= do { hsc_env <- getTopEnv