- ; let (bndrs, body) = collectBinders (occurAnalyseExpr ds_spec_expr)
- -- The occurrence-analysis does two things
- -- (a) identifies unused binders: Note [Unused spec binders]
- -- (b) sorts dict bindings into NonRecs
- -- so they can be inlined by decomposeRuleLhs
- mb_lhs = decomposeRuleLhs body
+ ; case (decomposeRuleLhs ds_spec_expr) of {
+ Nothing -> do { warnDs decomp_msg; return Nothing } ;