+-- | all is_ok bndrs -> mkLams bndrs (fiExpr to_drop real_body)
+-- [July 01: I'm experiment with getting the full laziness
+-- pass to floats bindings out past big lambdas (instead of the simplifier)
+-- so I don't want the float-in pass to just push them right back in.
+-- I'm going to try just dumping all bindings outside lambdas.]