diff options
Diffstat (limited to 'compiler/GHC/Core/Lint.hs')
| -rw-r--r-- | compiler/GHC/Core/Lint.hs | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/compiler/GHC/Core/Lint.hs b/compiler/GHC/Core/Lint.hs index 3438f372fc..a5da50bd1d 100644 --- a/compiler/GHC/Core/Lint.hs +++ b/compiler/GHC/Core/Lint.hs @@ -2116,7 +2116,8 @@ lintCoercion co@(UnivCo prov r ty1 ty2) ; checkWarnL (not lev_poly2) (report "right-hand type is levity-polymorphic") ; when (not (lev_poly1 || lev_poly2)) $ - do { checkWarnL (reps1 `equalLength` reps2) + do { checkWarnL (reps1 `equalLength` reps2 || + is_core_prep_prov prov) (report "between values with different # of reps") ; zipWithM_ validateCoercion reps1 reps2 }} where @@ -2128,6 +2129,13 @@ lintCoercion co@(UnivCo prov r ty1 ty2) reps1 = typePrimRep t1 reps2 = typePrimRep t2 + -- CorePrep deliberately makes ill-kinded casts + -- e.g (case error @Int "blah" of {}) :: Int# + -- ==> (error @Int "blah") |> Unsafe Int Int# + -- See Note [Unsafe coercions] in GHC.Core.CoreToStg.Prep + is_core_prep_prov CorePrepProv = True + is_core_prep_prov _ = False + validateCoercion :: PrimRep -> PrimRep -> LintM () validateCoercion rep1 rep2 = do { platform <- targetPlatform <$> getDynFlags @@ -2158,6 +2166,7 @@ lintCoercion co@(UnivCo prov r ty1 ty2) ; return (ProofIrrelProv kco') } lint_prov _ _ prov@(PluginProv _) = return prov + lint_prov _ _ prov@CorePrepProv = return prov check_kinds kco k1 k2 = do { let Pair k1' k2' = coercionKind kco |