s/MatchCx/TypeCx/

compiler/rustc_pattern_analysis/src/constructor.rs

@@ -40,7 +40,7 @@
 //! - That have no non-trivial intersection with any of the constructors in the column (i.e. they're
 //!     each either disjoint with or covered by any given column constructor).
 //!
-//! We compute this in two steps: first [`MatchCx::ctors_for_ty`] determines the
+//! We compute this in two steps: first [`TypeCx::ctors_for_ty`] determines the
 //! set of all possible constructors for the type. Then [`ConstructorSet::split`] looks at the
 //! column of constructors and splits the set into groups accordingly. The precise invariants of
 //! [`ConstructorSet::split`] is described in [`SplitConstructorSet`].
@@ -136,7 +136,7 @@
 //! the algorithm can't distinguish them from a nonempty constructor. The only known case where this
 //! could happen is the `[..]` pattern on `[!; N]` with `N > 0` so we must take care to not emit it.
 //!
-//! This is all handled by [`MatchCx::ctors_for_ty`] and
+//! This is all handled by [`TypeCx::ctors_for_ty`] and
 //! [`ConstructorSet::split`]. The invariants of [`SplitConstructorSet`] are also of interest.
 //!
 //!
@@ -163,7 +163,7 @@ use self::MaybeInfiniteInt::*;
 use self::SliceKind::*;
 
 use crate::usefulness::PlaceCtxt;
-use crate::MatchCx;
+use crate::TypeCx;
 
 /// Whether we have seen a constructor in the column or not.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
@@ -643,7 +643,7 @@ impl OpaqueId {
 /// constructor. `Constructor::apply` reconstructs the pattern from a pair of `Constructor` and
 /// `Fields`.
 #[derive(Clone, Debug, PartialEq)]
-pub enum Constructor<Cx: MatchCx> {
+pub enum Constructor<Cx: TypeCx> {
     /// Tuples and structs.
     Struct,
     /// Enum variants.
@@ -685,7 +685,7 @@ pub enum Constructor<Cx: MatchCx> {
     Missing,
 }
 
-impl<Cx: MatchCx> Constructor<Cx> {
+impl<Cx: TypeCx> Constructor<Cx> {
     pub(crate) fn is_non_exhaustive(&self) -> bool {
         matches!(self, NonExhaustive)
     }
@@ -798,7 +798,7 @@ pub enum VariantVisibility {
 /// In terms of division of responsibility, [`ConstructorSet::split`] handles all of the
 /// `exhaustive_patterns` feature.
 #[derive(Debug)]
-pub enum ConstructorSet<Cx: MatchCx> {
+pub enum ConstructorSet<Cx: TypeCx> {
     /// The type is a tuple or struct. `empty` tracks whether the type is empty.
     Struct { empty: bool },
     /// This type has the following list of constructors. If `variants` is empty and
@@ -846,13 +846,13 @@ pub enum ConstructorSet<Cx: MatchCx> {
 /// of the `ConstructorSet` for the type, yet if we forgot to include them in `present` we would be
 /// ignoring any row with `Opaque`s in the algorithm. Hence the importance of point 4.
 #[derive(Debug)]
-pub(crate) struct SplitConstructorSet<Cx: MatchCx> {
+pub(crate) struct SplitConstructorSet<Cx: TypeCx> {
     pub(crate) present: SmallVec<[Constructor<Cx>; 1]>,
     pub(crate) missing: Vec<Constructor<Cx>>,
     pub(crate) missing_empty: Vec<Constructor<Cx>>,
 }
 
-impl<Cx: MatchCx> ConstructorSet<Cx> {
+impl<Cx: TypeCx> ConstructorSet<Cx> {
     /// This analyzes a column of constructors to 1/ determine which constructors of the type (if
     /// any) are missing; 2/ split constructors to handle non-trivial intersections e.g. on ranges
     /// or slices. This can get subtle; see [`SplitConstructorSet`] for details of this operation

compiler/rustc_pattern_analysis/src/lib.rs

@@ -49,16 +49,16 @@ impl<'a, T: ?Sized> Captures<'a> for T {}
 /// Context that provides type information about constructors.
 ///
 /// Most of the crate is parameterized on a type that implements this trait.
-pub trait MatchCx: Sized + Clone + fmt::Debug {
+pub trait TypeCx: Sized + Clone + fmt::Debug {
     /// The type of a pattern.
     type Ty: Copy + Clone + fmt::Debug; // FIXME: remove Copy
     /// The index of an enum variant.
     type VariantIdx: Clone + Idx;
     /// A string literal
     type StrLit: Clone + PartialEq + fmt::Debug;
-    /// Extra data to store on a match arm.
+    /// Extra data to store in a match arm.
     type ArmData: Copy + Clone + fmt::Debug;
-    /// Extra data to store on a pattern. `Default` needed when we create fictitious wildcard
+    /// Extra data to store in a pattern. `Default` needed when we create fictitious wildcard
     /// patterns during analysis.
     type PatData: Clone + Default;
 
@@ -86,24 +86,24 @@ pub trait MatchCx: Sized + Clone + fmt::Debug {
 
 /// Context that provides information global to a match.
 #[derive(Clone)]
-pub struct MatchCtxt<'a, 'p, Cx: MatchCx> {
+pub struct MatchCtxt<'a, 'p, Cx: TypeCx> {
     /// The context for type information.
     pub tycx: &'a Cx,
     /// An arena to store the wildcards we produce during analysis.
     pub wildcard_arena: &'a TypedArena<DeconstructedPat<'p, Cx>>,
 }
 
-impl<'a, 'p, Cx: MatchCx> Copy for MatchCtxt<'a, 'p, Cx> {}
+impl<'a, 'p, Cx: TypeCx> Copy for MatchCtxt<'a, 'p, Cx> {}
 
 /// The arm of a match expression.
 #[derive(Clone, Debug)]
-pub struct MatchArm<'p, Cx: MatchCx> {
+pub struct MatchArm<'p, Cx: TypeCx> {
     pub pat: &'p DeconstructedPat<'p, Cx>,
     pub has_guard: bool,
     pub arm_data: Cx::ArmData,
 }
 
-impl<'p, Cx: MatchCx> Copy for MatchArm<'p, Cx> {}
+impl<'p, Cx: TypeCx> Copy for MatchArm<'p, Cx> {}
 
 /// The entrypoint for this crate. Computes whether a match is exhaustive and which of its arms are
 /// useful, and runs some lints.

compiler/rustc_pattern_analysis/src/lints.rs

@@ -15,7 +15,7 @@ use crate::rustc::{
     Constructor, DeconstructedPat, MatchArm, MatchCtxt, PlaceCtxt, RustcMatchCheckCtxt,
     SplitConstructorSet, WitnessPat,
 };
-use crate::MatchCx;
+use crate::TypeCx;
 
 /// A column of patterns in the matrix, where a column is the intuitive notion of "subpatterns that
 /// inspect the same subvalue/place".

compiler/rustc_pattern_analysis/src/pat.rs

@@ -7,7 +7,7 @@ use smallvec::{smallvec, SmallVec};
 
 use crate::constructor::{Constructor, Slice, SliceKind};
 use crate::usefulness::PlaceCtxt;
-use crate::{Captures, MatchCx};
+use crate::{Captures, TypeCx};
 
 use self::Constructor::*;
 
@@ -22,7 +22,7 @@ use self::Constructor::*;
 /// This happens if a private or `non_exhaustive` field is uninhabited, because the code mustn't
 /// observe that it is uninhabited. In that case that field is not included in `fields`. Care must
 /// be taken when converting to/from `thir::Pat`.
-pub struct DeconstructedPat<'p, Cx: MatchCx> {
+pub struct DeconstructedPat<'p, Cx: TypeCx> {
     ctor: Constructor<Cx>,
     fields: &'p [DeconstructedPat<'p, Cx>],
     ty: Cx::Ty,
@@ -31,7 +31,7 @@ pub struct DeconstructedPat<'p, Cx: MatchCx> {
     useful: Cell<bool>,
 }
 
-impl<'p, Cx: MatchCx> DeconstructedPat<'p, Cx> {
+impl<'p, Cx: TypeCx> DeconstructedPat<'p, Cx> {
     pub fn wildcard(ty: Cx::Ty, data: Cx::PatData) -> Self {
         Self::new(Wildcard, &[], ty, data)
     }
@@ -152,7 +152,7 @@ impl<'p, Cx: MatchCx> DeconstructedPat<'p, Cx> {
 
 /// This is mostly copied from the `Pat` impl. This is best effort and not good enough for a
 /// `Display` impl.
-impl<'p, Cx: MatchCx> fmt::Debug for DeconstructedPat<'p, Cx> {
+impl<'p, Cx: TypeCx> fmt::Debug for DeconstructedPat<'p, Cx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         Cx::debug_pat(f, self)
     }
@@ -161,13 +161,13 @@ impl<'p, Cx: MatchCx> fmt::Debug for DeconstructedPat<'p, Cx> {
 /// Same idea as `DeconstructedPat`, except this is a fictitious pattern built up for diagnostics
 /// purposes. As such they don't use interning and can be cloned.
 #[derive(Debug, Clone)]
-pub struct WitnessPat<Cx: MatchCx> {
+pub struct WitnessPat<Cx: TypeCx> {
     ctor: Constructor<Cx>,
     pub(crate) fields: Vec<WitnessPat<Cx>>,
     ty: Cx::Ty,
 }
 
-impl<Cx: MatchCx> WitnessPat<Cx> {
+impl<Cx: TypeCx> WitnessPat<Cx> {
     pub(crate) fn new(ctor: Constructor<Cx>, fields: Vec<Self>, ty: Cx::Ty) -> Self {
         Self { ctor, fields, ty }
     }

compiler/rustc_pattern_analysis/src/rustc.rs

@@ -20,7 +20,7 @@ use smallvec::SmallVec;
 use crate::constructor::{
     IntRange, MaybeInfiniteInt, OpaqueId, RangeEnd, Slice, SliceKind, VariantVisibility,
 };
-use crate::MatchCx;
+use crate::TypeCx;
 
 use crate::constructor::Constructor::*;
 
@@ -863,7 +863,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> {
     }
 }
 
-impl<'p, 'tcx> MatchCx for RustcMatchCheckCtxt<'p, 'tcx> {
+impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> {
     type Ty = Ty<'tcx>;
     type VariantIdx = VariantIdx;
     type StrLit = Const<'tcx>;

compiler/rustc_pattern_analysis/src/usefulness.rs

@@ -242,7 +242,7 @@
 //! Therefore `usefulness(tp_1, tp_2, tq)` returns the single witness-tuple `[Variant2(Some(true), 0)]`.
 //!
 //!
-//! Computing the set of constructors for a type is done in [`MatchCx::ctors_for_ty`]. See
+//! Computing the set of constructors for a type is done in [`TypeCx::ctors_for_ty`]. See
 //! the following sections for more accurate versions of the algorithm and corresponding links.
 //!
 //!
@@ -557,7 +557,7 @@ use std::fmt;
 
 use crate::constructor::{Constructor, ConstructorSet};
 use crate::pat::{DeconstructedPat, WitnessPat};
-use crate::{Captures, MatchArm, MatchCtxt, MatchCx, TypedArena};
+use crate::{Captures, MatchArm, MatchCtxt, TypeCx, TypedArena};
 
 use self::ValidityConstraint::*;
 
@@ -570,7 +570,7 @@ pub fn ensure_sufficient_stack<R>(f: impl FnOnce() -> R) -> R {
 
 /// Context that provides information local to a place under investigation.
 #[derive(Clone)]
-pub(crate) struct PlaceCtxt<'a, 'p, Cx: MatchCx> {
+pub(crate) struct PlaceCtxt<'a, 'p, Cx: TypeCx> {
     pub(crate) mcx: MatchCtxt<'a, 'p, Cx>,
     /// Type of the place under investigation.
     pub(crate) ty: Cx::Ty,
@@ -578,7 +578,7 @@ pub(crate) struct PlaceCtxt<'a, 'p, Cx: MatchCx> {
     pub(crate) is_scrutinee: bool,
 }
 
-impl<'a, 'p, Cx: MatchCx> PlaceCtxt<'a, 'p, Cx> {
+impl<'a, 'p, Cx: TypeCx> 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(mcx: MatchCtxt<'a, 'p, Cx>, ty: Cx::Ty) -> Self {
@@ -596,9 +596,9 @@ impl<'a, 'p, Cx: MatchCx> PlaceCtxt<'a, 'p, Cx> {
     }
 }
 
-impl<'a, 'p, Cx: MatchCx> Copy for PlaceCtxt<'a, 'p, Cx> {}
+impl<'a, 'p, Cx: TypeCx> Copy for PlaceCtxt<'a, 'p, Cx> {}
 
-impl<'a, 'p, Cx: MatchCx> fmt::Debug for PlaceCtxt<'a, 'p, Cx> {
+impl<'a, 'p, Cx: TypeCx> fmt::Debug for PlaceCtxt<'a, 'p, Cx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("PlaceCtxt").field("ty", &self.ty).finish()
     }
@@ -644,7 +644,7 @@ impl ValidityConstraint {
     ///
     /// Pending further opsem decisions, the current behavior is: validity is preserved, except
     /// inside `&` and union fields where validity is reset to `MaybeInvalid`.
-    fn specialize<Cx: MatchCx>(self, ctor: &Constructor<Cx>) -> Self {
+    fn specialize<Cx: TypeCx>(self, ctor: &Constructor<Cx>) -> Self {
         // We preserve validity except when we go inside a reference or a union field.
         if matches!(ctor, Constructor::Ref | Constructor::UnionField) {
             // Validity of `x: &T` does not imply validity of `*x: T`.
@@ -671,12 +671,12 @@ impl fmt::Display for ValidityConstraint {
 // - 'p coming from the input
 // - Cx global compilation context
 #[derive(Clone)]
-struct PatStack<'a, 'p, Cx: MatchCx> {
+struct PatStack<'a, 'p, Cx: TypeCx> {
     // Rows of len 1 are very common, which is why `SmallVec[_; 2]` works well.
     pats: SmallVec<[&'a DeconstructedPat<'p, Cx>; 2]>,
 }
 
-impl<'a, 'p, Cx: MatchCx> PatStack<'a, 'p, Cx> {
+impl<'a, 'p, Cx: TypeCx> PatStack<'a, 'p, Cx> {
     fn from_pattern(pat: &'a DeconstructedPat<'p, Cx>) -> Self {
         PatStack { pats: smallvec![pat] }
     }
@@ -722,7 +722,7 @@ impl<'a, 'p, Cx: MatchCx> PatStack<'a, 'p, Cx> {
     }
 }
 
-impl<'a, 'p, Cx: MatchCx> fmt::Debug for PatStack<'a, 'p, Cx> {
+impl<'a, 'p, Cx: TypeCx> fmt::Debug for PatStack<'a, 'p, Cx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // We pretty-print similarly to the `Debug` impl of `Matrix`.
         write!(f, "+")?;
@@ -735,7 +735,7 @@ impl<'a, 'p, Cx: MatchCx> fmt::Debug for PatStack<'a, 'p, Cx> {
 
 /// A row of the matrix.
 #[derive(Clone)]
-struct MatrixRow<'a, 'p, Cx: MatchCx> {
+struct MatrixRow<'a, 'p, Cx: TypeCx> {
     // The patterns in the row.
     pats: PatStack<'a, 'p, Cx>,
     /// Whether the original arm had a guard. This is inherited when specializing.
@@ -750,7 +750,7 @@ struct MatrixRow<'a, 'p, Cx: MatchCx> {
     useful: bool,
 }
 
-impl<'a, 'p, Cx: MatchCx> MatrixRow<'a, 'p, Cx> {
+impl<'a, 'p, Cx: TypeCx> MatrixRow<'a, 'p, Cx> {
     fn is_empty(&self) -> bool {
         self.pats.is_empty()
     }
@@ -795,7 +795,7 @@ impl<'a, 'p, Cx: MatchCx> MatrixRow<'a, 'p, Cx> {
     }
 }
 
-impl<'a, 'p, Cx: MatchCx> fmt::Debug for MatrixRow<'a, 'p, Cx> {
+impl<'a, 'p, Cx: TypeCx> fmt::Debug for MatrixRow<'a, 'p, Cx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.pats.fmt(f)
     }
@@ -812,7 +812,7 @@ impl<'a, 'p, Cx: MatchCx> fmt::Debug for MatrixRow<'a, 'p, Cx> {
 /// specializing `(,)` and `Some` on a pattern of type `(Option<u32>, bool)`, the first column of
 /// the matrix will correspond to `scrutinee.0.Some.0` and the second column to `scrutinee.1`.
 #[derive(Clone)]
-struct Matrix<'a, 'p, Cx: MatchCx> {
+struct Matrix<'a, 'p, Cx: TypeCx> {
     /// Vector of rows. The rows must form a rectangular 2D array. Moreover, all the patterns of
     /// each column must have the same type. Each column corresponds to a place within the
     /// scrutinee.
@@ -824,7 +824,7 @@ struct Matrix<'a, 'p, Cx: MatchCx> {
     place_validity: SmallVec<[ValidityConstraint; 2]>,
 }
 
-impl<'a, 'p, Cx: MatchCx> Matrix<'a, 'p, Cx> {
+impl<'a, 'p, Cx: TypeCx> Matrix<'a, 'p, Cx> {
     /// Pushes a new row to the matrix. If the row starts with an or-pattern, this recursively
     /// expands it. Internal method, prefer [`Matrix::new`].
     fn expand_and_push(&mut self, row: MatrixRow<'a, 'p, Cx>) {
@@ -942,7 +942,7 @@ impl<'a, 'p, Cx: MatchCx> Matrix<'a, 'p, Cx> {
 /// + _     + [_, _, tail @ ..] +
 /// | ✓     | ?                 | // column validity
 /// ```
-impl<'a, 'p, Cx: MatchCx> fmt::Debug for Matrix<'a, 'p, Cx> {
+impl<'a, 'p, Cx: TypeCx> fmt::Debug for Matrix<'a, 'p, Cx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "\n")?;
 
@@ -1033,9 +1033,9 @@ impl<'a, 'p, Cx: MatchCx> fmt::Debug for Matrix<'a, 'p, Cx> {
 ///
 /// See the top of the file for more detailed explanations and examples.
 #[derive(Debug, Clone)]
-struct WitnessStack<Cx: MatchCx>(Vec<WitnessPat<Cx>>);
+struct WitnessStack<Cx: TypeCx>(Vec<WitnessPat<Cx>>);
 
-impl<Cx: MatchCx> WitnessStack<Cx> {
+impl<Cx: TypeCx> WitnessStack<Cx> {
     /// Asserts that the witness contains a single pattern, and returns it.
     fn single_pattern(self) -> WitnessPat<Cx> {
         assert_eq!(self.0.len(), 1);
@@ -1080,9 +1080,9 @@ impl<Cx: MatchCx> WitnessStack<Cx> {
 /// Just as the `Matrix` starts with a single column, by the end of the algorithm, this has a single
 /// column, which contains the patterns that are missing for the match to be exhaustive.
 #[derive(Debug, Clone)]
-struct WitnessMatrix<Cx: MatchCx>(Vec<WitnessStack<Cx>>);
+struct WitnessMatrix<Cx: TypeCx>(Vec<WitnessStack<Cx>>);
 
-impl<Cx: MatchCx> WitnessMatrix<Cx> {
+impl<Cx: TypeCx> WitnessMatrix<Cx> {
     /// New matrix with no witnesses.
     fn empty() -> Self {
         WitnessMatrix(vec![])
@@ -1174,7 +1174,7 @@ impl<Cx: MatchCx> WitnessMatrix<Cx> {
 ///     (using `apply_constructor` and by updating `row.useful` for each parent row).
 /// This is all explained at the top of the file.
 #[instrument(level = "debug", skip(mcx, is_top_level), ret)]
-fn compute_exhaustiveness_and_usefulness<'a, 'p, Cx: MatchCx>(
+fn compute_exhaustiveness_and_usefulness<'a, 'p, Cx: TypeCx>(
     mcx: MatchCtxt<'a, 'p, Cx>,
     matrix: &mut Matrix<'a, 'p, Cx>,
     is_top_level: bool,
@@ -1283,7 +1283,7 @@ fn compute_exhaustiveness_and_usefulness<'a, 'p, Cx: MatchCx>(
 
 /// Indicates whether or not a given arm is useful.
 #[derive(Clone, Debug)]
-pub enum Usefulness<'p, Cx: MatchCx> {
+pub enum Usefulness<'p, Cx: TypeCx> {
     /// The arm is useful. This additionally carries a set of or-pattern branches that have been
     /// found to be redundant despite the overall arm being useful. Used only in the presence of
     /// or-patterns, otherwise it stays empty.
@@ -1294,7 +1294,7 @@ pub enum Usefulness<'p, Cx: MatchCx> {
 }
 
 /// The output of checking a match for exhaustiveness and arm usefulness.
-pub struct UsefulnessReport<'p, Cx: MatchCx> {
+pub struct UsefulnessReport<'p, Cx: TypeCx> {
     /// For each arm of the input, whether that arm is useful after the arms above it.
     pub arm_usefulness: Vec<(MatchArm<'p, Cx>, Usefulness<'p, Cx>)>,
     /// If the match is exhaustive, this is empty. If not, this contains witnesses for the lack of
@@ -1304,7 +1304,7 @@ pub struct UsefulnessReport<'p, Cx: MatchCx> {
 
 /// Computes whether a match is exhaustive and which of its arms are useful.
 #[instrument(skip(cx, arms), level = "debug")]
-pub fn compute_match_usefulness<'p, Cx: MatchCx>(
+pub fn compute_match_usefulness<'p, Cx: TypeCx>(
     cx: MatchCtxt<'_, 'p, Cx>,
     arms: &[MatchArm<'p, Cx>],
     scrut_ty: Cx::Ty,