Commit d9903544 authored by Simon Peyton Jones's avatar Simon Peyton Jones
Browse files

Improve the runRW magic in CorePrep

Instead of substituting, just augment the environment.
Less code, more efficient.

And the previous version had a bogus in-scope set which
triggered a WARNING
parent 6ec236b5
......@@ -516,15 +516,11 @@ cpeRhsE env (Var f `App` _{-type-} `App` arg)
| f `hasKey` lazyIdKey -- Replace (lazy a) by a
= cpeRhsE env arg -- See Note [lazyId magic] in MkId
cpeRhsE env (Var f `App` _{-levity-} `App` _{-type-} `App` arg)
cpeRhsE env (Var f `App` _levity `App` _type `App` arg)
-- See Note [runRW magic] in MkId
| f `hasKey` runRWKey -- Replace (runRW# f) by (f realWorld#),
= case arg of -- beta reducing if possible
Lam s body -> cpeRhsE env (substExpr (text "runRW#") subst body)
where subst = extendIdSubst emptySubst s (Var realWorldPrimId)
-- XXX I think we can use emptySubst here
-- because realWorldPrimId is a global variable
-- and so cannot be bound by a lambda in body
Lam s body -> cpeRhsE (extendCorePrepEnv env s realWorldPrimId) body
_ -> cpeRhsE env (arg `App` Var realWorldPrimId)
cpeRhsE env expr@(App {}) = cpeApp env expr
......@@ -1161,12 +1157,12 @@ allLazyNested is_rec (Floats IfUnboxedOk _) = isNonRec is_rec
-- The environment
-- ---------------------------------------------------------------------------
data CorePrepEnv = CPE {
cpe_dynFlags :: DynFlags,
cpe_env :: (IdEnv Id), -- Clone local Ids
cpe_mkIntegerId :: Id,
cpe_integerSDataCon :: Maybe DataCon
data CorePrepEnv
= CPE { cpe_dynFlags :: DynFlags
, cpe_env :: IdEnv Id -- Clone local Ids
, cpe_mkIntegerId :: Id
, cpe_integerSDataCon :: Maybe DataCon
lookupMkIntegerName :: DynFlags -> HscEnv -> IO Id
lookupMkIntegerName dflags hsc_env
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