diff options
Diffstat (limited to 'compiler/GHC/Core/TyCo/Compare.hs')
| -rw-r--r-- | compiler/GHC/Core/TyCo/Compare.hs | 30 |
1 files changed, 8 insertions, 22 deletions
diff --git a/compiler/GHC/Core/TyCo/Compare.hs b/compiler/GHC/Core/TyCo/Compare.hs index 4ef9d04eb8..a86c03d628 100644 --- a/compiler/GHC/Core/TyCo/Compare.hs +++ b/compiler/GHC/Core/TyCo/Compare.hs @@ -16,7 +16,7 @@ module GHC.Core.TyCo.Compare ( tcEqTyConApps, -- * Visiblity comparision - eqForAllVis, cmpForAllVis + eqForAllVis, ) where @@ -171,10 +171,9 @@ tc_eq_type keep_syns vis_only orig_ty1 orig_ty2 go _ (LitTy lit1) (LitTy lit2) = lit1 == lit2 - go env (ForAllTy (Bndr tv1 vis1) ty1) - (ForAllTy (Bndr tv2 vis2) ty2) - = vis1 `eqForAllVis` vis2 - && (vis_only || go env (varType tv1) (varType tv2)) + go env (ForAllTy (Bndr tv1 _) ty1) + (ForAllTy (Bndr tv2 _) ty2) + = (vis_only || go env (varType tv1) (varType tv2)) && go (rnBndr2 env tv1 tv2) ty1 ty2 -- Make sure we handle all FunTy cases since falling through to the @@ -224,7 +223,6 @@ tc_eq_type keep_syns vis_only orig_ty1 orig_ty2 {-# INLINE tc_eq_type #-} -- See Note [Specialising tc_eq_type]. - -- | Do these denote the same level of visibility? 'Required' -- arguments are visible, others are not. So this function -- equates 'Specified' and 'Inferred'. Used for printing. @@ -235,17 +233,6 @@ eqForAllVis Required Required = True eqForAllVis (Invisible _) (Invisible _) = True eqForAllVis _ _ = False --- | Do these denote the same level of visibility? 'Required' --- arguments are visible, others are not. So this function --- equates 'Specified' and 'Inferred'. Used for printing. -cmpForAllVis :: ForAllTyFlag -> ForAllTyFlag -> Ordering --- See Note [ForAllTy and type equality] --- If you change this, see IMPORTANT NOTE in the above Note -cmpForAllVis Required Required = EQ -cmpForAllVis Required (Invisible {}) = LT -cmpForAllVis (Invisible _) Required = GT -cmpForAllVis (Invisible _) (Invisible _) = EQ - {- Note [ForAllTy and type equality] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -253,7 +240,7 @@ When we compare (ForAllTy (Bndr tv1 vis1) ty1) and (ForAllTy (Bndr tv2 vis2) ty2) what should we do about `vis1` vs `vis2`. -First, we always compare with `eqForAllVis` and `cmpForAllVis`. +First, we always compare with `eqForAllVis`. But what decision do we make? Should GHC type-check the following program (adapted from #15740)? @@ -513,10 +500,9 @@ nonDetCmpTypeX env orig_t1 orig_t2 = go env (TyVarTy tv1) (TyVarTy tv2) = liftOrdering $ rnOccL env tv1 `nonDetCmpVar` rnOccR env tv2 - go env (ForAllTy (Bndr tv1 vis1) t1) (ForAllTy (Bndr tv2 vis2) t2) - = liftOrdering (vis1 `cmpForAllVis` vis2) - `thenCmpTy` go env (varType tv1) (varType tv2) - `thenCmpTy` go (rnBndr2 env tv1 tv2) t1 t2 + go env (ForAllTy (Bndr tv1 _) t1) (ForAllTy (Bndr tv2 _) t2) + = go env (varType tv1) (varType tv2) + `thenCmpTy` go (rnBndr2 env tv1 tv2) t1 t2 -- See Note [Equality on AppTys] go env (AppTy s1 t1) ty2 |