Stabilize `min_exhaustive_patterns`

4 files changed, 8 insertions, 23 deletions

diff --git a/compiler/rustc_pattern_analysis/src/lib.rs b/compiler/rustc_pattern_analysis/src/lib.rs
index a5c0b13c90b..e37fa072b6d 100644
--- a/compiler/rustc_pattern_analysis/src/lib.rs
+++ b/compiler/rustc_pattern_analysis/src/lib.rs
@@ -54,7 +54,6 @@ pub trait PatCx: Sized + fmt::Debug {
     type PatData: Clone;
 
     fn is_exhaustive_patterns_feature_on(&self) -> bool;
-    fn is_min_exhaustive_patterns_feature_on(&self) -> bool;
 
     /// The number of fields for this constructor.
     fn ctor_arity(&self, ctor: &Constructor<Self>, ty: &Self::Ty) -> usize;
diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs
index 6290aeb2523..25f7cc17c11 100644
--- a/compiler/rustc_pattern_analysis/src/rustc.rs
+++ b/compiler/rustc_pattern_analysis/src/rustc.rs
@@ -237,9 +237,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                         let tys = cx.variant_sub_tys(ty, variant).map(|(field, ty)| {
                             let is_visible =
                                 adt.is_enum() || field.vis.is_accessible_from(cx.module, cx.tcx);
-                            let is_uninhabited = (cx.tcx.features().exhaustive_patterns
-                                || cx.tcx.features().min_exhaustive_patterns)
-                                && cx.is_uninhabited(*ty);
+                            let is_uninhabited = cx.is_uninhabited(*ty);
                             let skip = is_uninhabited && (!is_visible || is_non_exhaustive);
                             (ty, PrivateUninhabitedField(skip))
                         });
@@ -925,9 +923,6 @@ impl<'p, 'tcx: 'p> PatCx for RustcPatCtxt<'p, 'tcx> {
     fn is_exhaustive_patterns_feature_on(&self) -> bool {
         self.tcx.features().exhaustive_patterns
     }
-    fn is_min_exhaustive_patterns_feature_on(&self) -> bool {
-        self.tcx.features().min_exhaustive_patterns
-    }
 
     fn ctor_arity(&self, ctor: &crate::constructor::Constructor<Self>, ty: &Self::Ty) -> usize {
         self.ctor_arity(ctor, *ty)
diff --git a/compiler/rustc_pattern_analysis/src/usefulness.rs b/compiler/rustc_pattern_analysis/src/usefulness.rs
index 9710c9e1303..6535afcc398 100644
--- a/compiler/rustc_pattern_analysis/src/usefulness.rs
+++ b/compiler/rustc_pattern_analysis/src/usefulness.rs
@@ -543,13 +543,11 @@
 //! recurse into subpatterns. That second part is done through [`PlaceValidity`], most notably
 //! [`PlaceValidity::specialize`].
 //!
-//! Having said all that, in practice we don't fully follow what's been presented in this section.
-//! Let's call "toplevel exception" the case where the match scrutinee itself has type `!` or
-//! `EmptyEnum`. First, on stable rust, we require `_` patterns for empty types in all cases apart
-//! from the toplevel exception. The `exhaustive_patterns` and `min_exaustive_patterns` allow
-//! omitting patterns in the cases described above. There's a final detail: in the toplevel
-//! exception or with the `exhaustive_patterns` feature, we ignore place validity when checking
-//! whether a pattern is required for exhaustiveness. I (Nadrieril) hope to deprecate this behavior.
+//! Having said all that, we don't fully follow what's been presented in this section. For
+//! backwards-compatibility, we ignore place validity when checking whether a pattern is required
+//! for exhaustiveness in two cases: when the `exhaustive_patterns` feature gate is on, or when the
+//! match scrutinee itself has type `!` or `EmptyEnum`. I (Nadrieril) hope to deprecate this
+//! exception.
 //!
 //!
 //!
@@ -953,13 +951,10 @@ impl<Cx: PatCx> PlaceInfo<Cx> {
             self.is_scrutinee && matches!(ctors_for_ty, ConstructorSet::NoConstructors);
         // Whether empty patterns are counted as useful or not. We only warn an empty arm unreachable if
         // it is guaranteed unreachable by the opsem (i.e. if the place is `known_valid`).
-        let empty_arms_are_unreachable = self.validity.is_known_valid()
-            && (is_toplevel_exception
-                || cx.is_exhaustive_patterns_feature_on()
-                || cx.is_min_exhaustive_patterns_feature_on());
+        let empty_arms_are_unreachable = self.validity.is_known_valid();
         // Whether empty patterns can be omitted for exhaustiveness. We ignore place validity in the
         // toplevel exception and `exhaustive_patterns` cases for backwards compatibility.
-        let can_omit_empty_arms = empty_arms_are_unreachable
+        let can_omit_empty_arms = self.validity.is_known_valid()
             || is_toplevel_exception
             || cx.is_exhaustive_patterns_feature_on();
 
diff --git a/compiler/rustc_pattern_analysis/tests/common/mod.rs b/compiler/rustc_pattern_analysis/tests/common/mod.rs
index 01a56eaa78f..ec0bcd43ad2 100644
--- a/compiler/rustc_pattern_analysis/tests/common/mod.rs
+++ b/compiler/rustc_pattern_analysis/tests/common/mod.rs
@@ -152,10 +152,6 @@ impl PatCx for Cx {
         false
     }
 
-    fn is_min_exhaustive_patterns_feature_on(&self) -> bool {
-        true
-    }
-
     fn ctor_arity(&self, ctor: &Constructor<Self>, ty: &Self::Ty) -> usize {
         ty.sub_tys(ctor).len()
     }