rnValBindsRHSGen trim bound_names (ValBindsIn mbinds sigs) = do
-- rename the sigs
- env <- getGblEnv
- traceRn (ptext (sLit "Rename sigs") <+> ppr (tcg_rdr_env env))
sigs' <- renameSigs (Just (mkNameSet bound_names)) okBindSig sigs
-- rename the RHSes
binds_w_dus <- mapBagM (rnBind (mkSigTvFn sigs') trim) mbinds
-- No scoped type variables for pattern bindings
; let fvs' = trim fvs
- ; fvs' `seq`
+ ; fvs' `seq` -- See Note [Free-variable space leak]
return (L loc (PatBind { pat_lhs = pat,
pat_rhs = grhss',
pat_rhs_ty = placeHolderType,
; checkPrecMatch inf plain_name matches'
- ; fvs' `seq`
+ ; fvs' `seq` -- See Note [Free-variable space leak]
return (L loc (FunBind { fun_id = name,
fun_infix = inf,
fun_matches = matches',
}
rnBind _ _ b = pprPanic "rnBind" (ppr b)
-
+
+{-
+Note [Free-variable space leak]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+We have
+ fvs' = trim fvs
+and we seq fvs' before turning it as part of a record.
+
+The reason is that trim is sometimes something like
+ \xs -> intersectNameSet (mkNameSet bound_names) xs
+and we don't want to retain the list bound_names. This showed up in
+trac ticket #1136.
+-}
+
---------------------
depAnalBinds :: Bag (LHsBind Name, [Name], Uses)
-> ([(RecFlag, LHsBinds Name)], DefUses)