s/PatCtxt/PlaceCtxt/

compiler/rustc_pattern_analysis/src/constructor.rs

@@ -162,7 +162,7 @@ use self::Constructor::*;
 use self::MaybeInfiniteInt::*;
 use self::SliceKind::*;
 
-use crate::usefulness::PatCtxt;
+use crate::usefulness::PlaceCtxt;
 use crate::MatchCx;
 
 /// Whether we have seen a constructor in the column or not.
@@ -717,7 +717,7 @@ impl<Cx: MatchCx> Constructor<Cx> {
 
     /// The number of fields for this constructor. This must be kept in sync with
     /// `Fields::wildcards`.
-    pub(crate) fn arity(&self, pcx: &PatCtxt<'_, '_, Cx>) -> usize {
+    pub(crate) fn arity(&self, pcx: &PlaceCtxt<'_, '_, Cx>) -> usize {
         pcx.cx.ctor_arity(self, pcx.ty)
     }
 
@@ -726,7 +726,7 @@ impl<Cx: MatchCx> Constructor<Cx> {
     /// this checks for inclusion.
     // We inline because this has a single call site in `Matrix::specialize_constructor`.
     #[inline]
-    pub(crate) fn is_covered_by<'p>(&self, pcx: &PatCtxt<'_, 'p, Cx>, other: &Self) -> bool {
+    pub(crate) fn is_covered_by<'p>(&self, pcx: &PlaceCtxt<'_, 'p, Cx>, other: &Self) -> bool {
         match (self, other) {
             (Wildcard, _) => pcx
                 .cx
@@ -859,7 +859,7 @@ impl<Cx: MatchCx> ConstructorSet<Cx> {
     #[instrument(level = "debug", skip(self, pcx, ctors), ret)]
     pub(crate) fn split<'a>(
         &self,
-        pcx: &PatCtxt<'_, '_, Cx>,
+        pcx: &PlaceCtxt<'_, '_, Cx>,
         ctors: impl Iterator<Item = &'a Constructor<Cx>> + Clone,
     ) -> SplitConstructorSet<Cx>
     where
@@ -1008,7 +1008,7 @@ impl<Cx: MatchCx> ConstructorSet<Cx> {
         // In the absence of the `exhaustive_patterns` feature however, we don't count nested empty
         // types as empty. Only non-nested `!` or `enum Foo {}` are considered empty.
         if !pcx.cx.is_exhaustive_patterns_feature_on()
-            && !(pcx.is_top_level && matches!(self, Self::NoConstructors))
+            && !(pcx.is_scrutinee && matches!(self, Self::NoConstructors))
         {
             // Treat all missing constructors as nonempty.
             // This clears `missing_empty`.

compiler/rustc_pattern_analysis/src/lints.rs

@@ -13,7 +13,7 @@ use crate::errors::{
     OverlappingRangeEndpoints, Uncovered,
 };
 use crate::rustc::{
-    Constructor, DeconstructedPat, MatchArm, PatCtxt, RustcMatchCheckCtxt, SplitConstructorSet,
+    Constructor, DeconstructedPat, MatchArm, PlaceCtxt, RustcMatchCheckCtxt, SplitConstructorSet,
     WitnessPat,
 };
 use crate::MatchCx;
@@ -68,7 +68,7 @@ impl<'a, 'p, 'tcx> PatternColumn<'a, 'p, 'tcx> {
     }
 
     /// Do constructor splitting on the constructors of the column.
-    fn analyze_ctors(&self, pcx: &PatCtxt<'_, 'p, 'tcx>) -> SplitConstructorSet<'p, 'tcx> {
+    fn analyze_ctors(&self, pcx: &PlaceCtxt<'_, 'p, 'tcx>) -> SplitConstructorSet<'p, 'tcx> {
         let column_ctors = self.patterns.iter().map(|p| p.ctor());
         pcx.cx.ctors_for_ty(pcx.ty).split(pcx, column_ctors)
     }
@@ -84,7 +84,7 @@ impl<'a, 'p, 'tcx> PatternColumn<'a, 'p, 'tcx> {
     /// which may change the lengths.
     fn specialize(
         &self,
-        pcx: &PatCtxt<'a, 'p, 'tcx>,
+        pcx: &PlaceCtxt<'a, 'p, 'tcx>,
         ctor: &Constructor<'p, 'tcx>,
     ) -> Vec<PatternColumn<'a, 'p, 'tcx>> {
         let arity = ctor.arity(pcx);
@@ -130,7 +130,7 @@ fn collect_nonexhaustive_missing_variants<'a, 'p, 'tcx>(
     let Some(ty) = column.head_ty() else {
         return Vec::new();
     };
-    let pcx = &PatCtxt::new_dummy(cx, ty, wildcard_arena);
+    let pcx = &PlaceCtxt::new_dummy(cx, ty, wildcard_arena);
 
     let set = column.analyze_ctors(pcx);
     if set.present.is_empty() {
@@ -232,7 +232,7 @@ pub(crate) fn lint_overlapping_range_endpoints<'a, 'p, 'tcx>(
     let Some(ty) = column.head_ty() else {
         return;
     };
-    let pcx = &PatCtxt::new_dummy(cx, ty, wildcard_arena);
+    let pcx = &PlaceCtxt::new_dummy(cx, ty, wildcard_arena);
 
     let set = column.analyze_ctors(pcx);
 

compiler/rustc_pattern_analysis/src/pat.rs

@@ -6,7 +6,7 @@ use std::fmt;
 use smallvec::{smallvec, SmallVec};
 
 use crate::constructor::{Constructor, Slice, SliceKind};
-use crate::usefulness::PatCtxt;
+use crate::usefulness::PlaceCtxt;
 use crate::{Captures, MatchCx};
 
 use self::Constructor::*;
@@ -77,7 +77,7 @@ impl<'p, Cx: MatchCx> DeconstructedPat<'p, Cx> {
     /// `other_ctor` can be different from `self.ctor`, but must be covered by it.
     pub(crate) fn specialize<'a>(
         &self,
-        pcx: &PatCtxt<'a, 'p, Cx>,
+        pcx: &PlaceCtxt<'a, 'p, Cx>,
         other_ctor: &Constructor<Cx>,
     ) -> SmallVec<[&'a DeconstructedPat<'p, Cx>; 2]> {
         let wildcard_sub_tys = || {
@@ -178,7 +178,7 @@ impl<Cx: MatchCx> WitnessPat<Cx> {
     /// Construct a pattern that matches everything that starts with this constructor.
     /// For example, if `ctor` is a `Constructor::Variant` for `Option::Some`, we get the pattern
     /// `Some(_)`.
-    pub(crate) fn wild_from_ctor(pcx: &PatCtxt<'_, '_, Cx>, ctor: Constructor<Cx>) -> Self {
+    pub(crate) fn wild_from_ctor(pcx: &PlaceCtxt<'_, '_, Cx>, ctor: Constructor<Cx>) -> Self {
         let field_tys = pcx.cx.ctor_sub_tys(&ctor, pcx.ty);
         let fields = field_tys.iter().map(|ty| Self::wildcard(*ty)).collect();
         Self::new(ctor, fields, pcx.ty)

compiler/rustc_pattern_analysis/src/rustc.rs

@@ -31,8 +31,8 @@ pub type ConstructorSet<'p, 'tcx> =
 pub type DeconstructedPat<'p, 'tcx> =
     crate::pat::DeconstructedPat<'p, RustcMatchCheckCtxt<'p, 'tcx>>;
 pub type MatchArm<'p, 'tcx> = crate::MatchArm<'p, RustcMatchCheckCtxt<'p, 'tcx>>;
-pub(crate) type PatCtxt<'a, 'p, 'tcx> =
-    crate::usefulness::PatCtxt<'a, 'p, RustcMatchCheckCtxt<'p, 'tcx>>;
+pub(crate) type PlaceCtxt<'a, 'p, 'tcx> =
+    crate::usefulness::PlaceCtxt<'a, 'p, RustcMatchCheckCtxt<'p, 'tcx>>;
 pub(crate) type SplitConstructorSet<'p, 'tcx> =
     crate::constructor::SplitConstructorSet<RustcMatchCheckCtxt<'p, 'tcx>>;
 pub type Usefulness<'p, 'tcx> = crate::usefulness::Usefulness<'p, RustcMatchCheckCtxt<'p, 'tcx>>;

compiler/rustc_pattern_analysis/src/usefulness.rs

@@ -575,35 +575,35 @@ pub fn ensure_sufficient_stack<R>(f: impl FnOnce() -> R) -> R {
     f()
 }
 
+/// Context that provides information local to a place under investigation.
 #[derive(Clone)]
-pub(crate) struct PatCtxt<'a, 'p, Cx: MatchCx> {
+pub(crate) struct PlaceCtxt<'a, 'p, Cx: MatchCx> {
     pub(crate) cx: &'a Cx,
-    /// Type of the current column under investigation.
-    pub(crate) ty: Cx::Ty,
-    /// Whether the current pattern is the whole pattern as found in a match arm, or if it's a
-    /// subpattern.
-    pub(crate) is_top_level: bool,
     /// An arena to store the wildcards we produce during analysis.
     pub(crate) wildcard_arena: &'a TypedArena<DeconstructedPat<'p, Cx>>,
+    /// Type of the place under investigation.
+    pub(crate) ty: Cx::Ty,
+    /// Whether the place is the original scrutinee place, as opposed to a subplace of it.
+    pub(crate) is_scrutinee: bool,
 }
 
-impl<'a, 'p, Cx: MatchCx> PatCtxt<'a, 'p, Cx> {
-    /// A `PatCtxt` when code other than `is_useful` needs one.
+impl<'a, 'p, Cx: MatchCx> PlaceCtxt<'a, 'p, Cx> {
+    /// A `PlaceCtxt` when code other than `is_useful` needs one.
     #[cfg_attr(not(feature = "rustc"), allow(dead_code))]
     pub(crate) fn new_dummy(
         cx: &'a Cx,
         ty: Cx::Ty,
         wildcard_arena: &'a TypedArena<DeconstructedPat<'p, Cx>>,
     ) -> Self {
-        PatCtxt { cx, ty, is_top_level: false, wildcard_arena }
+        PlaceCtxt { cx, ty, is_scrutinee: false, wildcard_arena }
     }
 }
 
-impl<'a, 'p, Cx: MatchCx> Copy for PatCtxt<'a, 'p, Cx> {}
+impl<'a, 'p, Cx: MatchCx> Copy for PlaceCtxt<'a, 'p, Cx> {}
 
-impl<'a, 'p, Cx: MatchCx> fmt::Debug for PatCtxt<'a, 'p, Cx> {
+impl<'a, 'p, Cx: MatchCx> fmt::Debug for PlaceCtxt<'a, 'p, Cx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("PatCtxt").field("ty", &self.ty).finish()
+        f.debug_struct("PlaceCtxt").field("ty", &self.ty).finish()
     }
 }
 
@@ -714,7 +714,7 @@ impl<'a, 'p, Cx: MatchCx> PatStack<'a, 'p, Cx> {
     /// Only call if `ctor.is_covered_by(self.head().ctor())` is true.
     fn pop_head_constructor(
         &self,
-        pcx: &PatCtxt<'a, 'p, Cx>,
+        pcx: &PlaceCtxt<'a, 'p, Cx>,
         ctor: &Constructor<Cx>,
     ) -> PatStack<'a, 'p, Cx> {
         // We pop the head pattern and push the new fields extracted from the arguments of
@@ -785,7 +785,7 @@ impl<'a, 'p, Cx: MatchCx> MatrixRow<'a, 'p, Cx> {
     /// Only call if `ctor.is_covered_by(self.head().ctor())` is true.
     fn pop_head_constructor(
         &self,
-        pcx: &PatCtxt<'a, 'p, Cx>,
+        pcx: &PlaceCtxt<'a, 'p, Cx>,
         ctor: &Constructor<Cx>,
         parent_row: usize,
     ) -> MatrixRow<'a, 'p, Cx> {
@@ -914,7 +914,7 @@ impl<'a, 'p, Cx: MatchCx> Matrix<'a, 'p, Cx> {
     /// This computes `specialize(ctor, self)`. See top of the file for explanations.
     fn specialize_constructor(
         &self,
-        pcx: &PatCtxt<'a, 'p, Cx>,
+        pcx: &PlaceCtxt<'a, 'p, Cx>,
         ctor: &Constructor<Cx>,
     ) -> Matrix<'a, 'p, Cx> {
         let wildcard_row = self.wildcard_row.pop_head_constructor(pcx, ctor);
@@ -1064,7 +1064,7 @@ impl<Cx: MatchCx> WitnessStack<Cx> {
     /// pats: [(false, "foo"), _, true]
     /// result: [Enum::Variant { a: (false, "foo"), b: _ }, true]
     /// ```
-    fn apply_constructor(&mut self, pcx: &PatCtxt<'_, '_, Cx>, ctor: &Constructor<Cx>) {
+    fn apply_constructor(&mut self, pcx: &PlaceCtxt<'_, '_, Cx>, ctor: &Constructor<Cx>) {
         let len = self.0.len();
         let arity = ctor.arity(pcx);
         let fields = self.0.drain((len - arity)..).rev().collect();
@@ -1114,7 +1114,7 @@ impl<Cx: MatchCx> WitnessMatrix<Cx> {
     /// Reverses specialization by `ctor`. See the section on `unspecialize` at the top of the file.
     fn apply_constructor(
         &mut self,
-        pcx: &PatCtxt<'_, '_, Cx>,
+        pcx: &PlaceCtxt<'_, '_, Cx>,
         missing_ctors: &[Constructor<Cx>],
         ctor: &Constructor<Cx>,
         report_individual_missing_ctors: bool,
@@ -1202,7 +1202,7 @@ fn compute_exhaustiveness_and_usefulness<'a, 'p, Cx: MatchCx>(
     };
 
     debug!("ty: {ty:?}");
-    let pcx = &PatCtxt { cx, ty, is_top_level, wildcard_arena };
+    let pcx = &PlaceCtxt { cx, ty, is_scrutinee: is_top_level, wildcard_arena };
 
     // Whether the place/column we are inspecting is known to contain valid data.
     let place_validity = matrix.place_validity[0];