tidyUnfolding tidy_env
              unf@(CoreUnfolding { uf_tmpl = unf_rhs, uf_src = src })
              unf_from_rhs
  | isStableSource src
  = unf { uf_tmpl = tidyExpr tidy_env unf_rhs }    -- Preserves OccInfo
  | otherwise
  = unf_from_rhs
tidyUnfolding tidy_env
              unf@(CoreUnfolding { uf_tmpl = unf_rhs, uf_src = src })
              unf_from_rhs
  | isStableSource src
  = unf { uf_tmpl = tidyExpr tidy_env unf_rhs }    -- Preserves OccInfo
  | otherwise
  = unf_from_rhs
tidyUnfolding tidy_env
              unf@(CoreUnfolding { uf_tmpl = unf_rhs, uf_src = src })
              unf_from_rhs
  | isStableSource src
  = unf { uf_tmpl = tidyExpr tidy_env unf_rhs }    -- Preserves OccInfo
  | otherwise
  = unf_from_rhs