bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Limit the use of PlaceCtxt

Browse source
This commit is contained in:
Nadrieril 2024-01-24 21:16:57 +01:00
parent 0b2579a1b6
commit cb0e8c508c
6 changed files with 42 additions and 52 deletions
Download patch file Download diff file Expand all files Collapse all files

34
compiler/rustc_pattern_analysis/src/usefulness.rs
View file

@ -731,20 +731,19 @@ pub fn ensure_sufficient_stack<R>(f: impl FnOnce() -> R) -> R {
}
/// Context that provides information local to a place under investigation.
pub(crate) struct PlaceCtxt<'a, Cx: TypeCx> {
pub(crate) mcx: MatchCtxt<'a, Cx>,
struct PlaceCtxt<'a, Cx: TypeCx> {
mcx: MatchCtxt<'a, Cx>,
/// Type of the place under investigation.
pub(crate) ty: &'a Cx::Ty,
ty: &'a Cx::Ty,
}
impl<'a, Cx: TypeCx> Copy for PlaceCtxt<'a, Cx> {}
impl<'a, Cx: TypeCx> Clone for PlaceCtxt<'a, Cx> {
fn clone(&self) -> Self {
Self { mcx: self.mcx, ty: self.ty }
}
}
impl<'a, Cx: TypeCx> Copy for PlaceCtxt<'a, Cx> {}
impl<'a, Cx: TypeCx> fmt::Debug for PlaceCtxt<'a, Cx> {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("PlaceCtxt").field("ty", self.ty).finish()
@ -752,24 +751,21 @@ impl<'a, Cx: TypeCx> fmt::Debug for PlaceCtxt<'a, Cx> {
}
impl<'a, Cx: TypeCx> PlaceCtxt<'a, 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, Cx>, ty: &'a Cx::Ty) -> Self {
PlaceCtxt { mcx, ty }
}
pub(crate) fn ctor_arity(&self, ctor: &Constructor<Cx>) -> usize {
fn ctor_arity(&self, ctor: &Constructor<Cx>) -> usize {
self.mcx.tycx.ctor_arity(ctor, self.ty)
}
pub(crate) fn ctor_sub_tys(
fn ctor_sub_tys(
&'a self,
ctor: &'a Constructor<Cx>,
) -> impl Iterator<Item = Cx::Ty> + ExactSizeIterator + Captures<'a> {
self.mcx.tycx.ctor_sub_tys(ctor, self.ty)
}
pub(crate) fn ctors_for_ty(&self) -> Result<ConstructorSet<Cx>, Cx::Error> {
fn ctors_for_ty(&self) -> Result<ConstructorSet<Cx>, Cx::Error> {
self.mcx.tycx.ctors_for_ty(self.ty)
}
fn wild_from_ctor(&self, ctor: Constructor<Cx>) -> WitnessPat<Cx> {
WitnessPat::wild_from_ctor(self.mcx.tycx, ctor, self.ty.clone())
}
}
/// Serves two purposes:
@ -1089,7 +1085,7 @@ impl<'p, Cx: TypeCx> Matrix<'p, Cx> {
wildcard_row_is_relevant: self.wildcard_row_is_relevant && ctor_is_relevant,
};
for (i, row) in self.rows().enumerate() {
if ctor.is_covered_by(pcx, row.head().ctor()) {
if ctor.is_covered_by(pcx.mcx.tycx, row.head().ctor()) {
let new_row = row.pop_head_constructor(ctor, arity, ctor_is_relevant, i);
matrix.expand_and_push(new_row);
}
@ -1240,7 +1236,7 @@ impl<Cx: TypeCx> WitnessStack<Cx> {
/// ```
fn apply_constructor(&mut self, pcx: &PlaceCtxt<'_, Cx>, ctor: &Constructor<Cx>) {
let len = self.0.len();
let arity = ctor.arity(pcx);
let arity = pcx.ctor_arity(ctor);
let fields = self.0.drain((len - arity)..).rev().collect();
let pat = WitnessPat::new(ctor.clone(), fields, pcx.ty.clone());
self.0.push(pat);
@ -1315,20 +1311,20 @@ impl<Cx: TypeCx> WitnessMatrix<Cx> {
*self = Self::empty();
} else if !report_individual_missing_ctors {
// Report `_` as missing.
let pat = WitnessPat::wild_from_ctor(pcx, Constructor::Wildcard);
let pat = pcx.wild_from_ctor(Constructor::Wildcard);
self.push_pattern(pat);
} else if missing_ctors.iter().any(|c| c.is_non_exhaustive()) {
// We need to report a `_` anyway, so listing other constructors would be redundant.
// `NonExhaustive` is displayed as `_` just like `Wildcard`, but it will be picked
// up by diagnostics to add a note about why `_` is required here.
let pat = WitnessPat::wild_from_ctor(pcx, Constructor::NonExhaustive);
let pat = pcx.wild_from_ctor(Constructor::NonExhaustive);
self.push_pattern(pat);
} else {
// For each missing constructor `c`, we add a `c(_, _, _)` witness appropriately
// filled with wildcards.
let mut ret = Self::empty();
for ctor in missing_ctors {
let pat = WitnessPat::wild_from_ctor(pcx, ctor.clone());
let pat = pcx.wild_from_ctor(ctor.clone());
// Clone `self` and add `c(_, _, _)` to each of its witnesses.
let mut wit_matrix = self.clone();
wit_matrix.push_pattern(pat);