diff options
Diffstat (limited to 'compiler/coreSyn/CoreSubst.hs')
| -rw-r--r-- | compiler/coreSyn/CoreSubst.hs | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/compiler/coreSyn/CoreSubst.hs b/compiler/coreSyn/CoreSubst.hs index 73be490edb..d98536caec 100644 --- a/compiler/coreSyn/CoreSubst.hs +++ b/compiler/coreSyn/CoreSubst.hs @@ -502,7 +502,7 @@ substIdBndr _doc rec_subst subst@(Subst in_scope env tvs cvs) old_id old_ty = idType old_id no_type_change = (isEmptyVarEnv tvs && isEmptyVarEnv cvs) || - isEmptyVarSet (tyCoVarsOfType old_ty) + noFreeVarsOfType old_ty -- new_id has the right IdInfo -- The lazy-set is because we're in a loop here, with @@ -622,7 +622,7 @@ substCo subst co = Coercion.substCo (getTCvSubst subst) co substIdType :: Subst -> Id -> Id substIdType subst@(Subst _ _ tv_env cv_env) id - | (isEmptyVarEnv tv_env && isEmptyVarEnv cv_env) || isEmptyVarSet (tyCoVarsOfType old_ty) = id + | (isEmptyVarEnv tv_env && isEmptyVarEnv cv_env) || noFreeVarsOfType old_ty = id | otherwise = setIdType id (substTy subst old_ty) -- The tyCoVarsOfType is cheaper than it looks -- because we cache the free tyvars of the type @@ -1058,7 +1058,12 @@ maybe_substitute subst b r , isAlwaysActive (idInlineActivation b) -- Note [Inline prag in simplOpt] , not (isStableUnfolding (idUnfolding b)) , not (isExportedId b) - , not (isUnliftedType (idType b)) || exprOkForSpeculation r + , let id_ty = idType b + -- A levity-polymorphic id? Impossible you say? + -- See Note [Levity polymorphism invariants] in CoreSyn + -- Ah, but it *is* possible in the compulsory unfolding of unsafeCoerce# + -- This check prevents the isUnliftedType check from panicking. + , isTypeLevPoly id_ty || not (isUnliftedType (idType b)) || exprOkForSpeculation r = Just (extendIdSubst subst b r) | otherwise |