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Rollup merge of #120331 - Nadrieril:no-arena, r=compiler-errors

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pattern_analysis: use a plain `Vec` in `DeconstructedPat`

The use of an arena-allocated slice in `DeconstructedPat` dates to when we needed the arena anyway for lifetime reasons. Now that we don't, I'm thinking that if `thir::Pat` can use plain old `Vec`s, maybe so can I.

r? ```@ghost```
This commit is contained in:
Matthias Krüger 2024-02-06 22:45:40 +01:00 committed by GitHub
parent 3c52832375 f65fe3ba59
commit ce32d4862b
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GPG key ID: B5690EEEBB952194
7 changed files with 61 additions and 64 deletions
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3
compiler/rustc_mir_build/src/thir/pattern/check_match.rs
View file

@ -291,7 +291,7 @@ fn lower_pattern(
err = err.and(check_never_pattern(cx, pat));
});
err?;
Ok(cx.pattern_arena.alloc(cx.lower_pat(pat)))
Ok(self.pattern_arena.alloc(cx.lower_pat(pat)))
}
}
@ -388,7 +388,6 @@ fn new_cx(
typeck_results: self.typeck_results,
param_env: self.param_env,
module: self.tcx.parent_module(self.lint_level).to_def_id(),
pattern_arena: self.pattern_arena,
dropless_arena: self.dropless_arena,
match_lint_level: self.lint_level,
whole_match_span,

5
compiler/rustc_pattern_analysis/src/errors.rs
View file

@ -23,7 +23,10 @@ pub fn new<'p>(
span: Span,
cx: &RustcMatchCheckCtxt<'p, 'tcx>,
witnesses: Vec<WitnessPat<'p, 'tcx>>,
) -> Self {
) -> Self
where
'tcx: 'p,
{
let witness_1 = cx.hoist_witness_pat(witnesses.get(0).unwrap());
Self {
span,

8
compiler/rustc_pattern_analysis/src/lib.rs
View file

@ -119,7 +119,7 @@ fn ctor_sub_tys<'a>(
/// `DeconstructedPat`. Only invoqued when `pat.ctor()` is `Struct | Variant(_) | UnionField`.
fn write_variant_name(
f: &mut fmt::Formatter<'_>,
pat: &crate::pat::DeconstructedPat<'_, Self>,
pat: &crate::pat::DeconstructedPat<Self>,
) -> fmt::Result;
/// Raise a bug.
@ -130,9 +130,9 @@ fn write_variant_name(
/// The default implementation does nothing.
fn lint_overlapping_range_endpoints(
&self,
_pat: &DeconstructedPat<'_, Self>,
_pat: &DeconstructedPat<Self>,
_overlaps_on: IntRange,
_overlaps_with: &[&DeconstructedPat<'_, Self>],
_overlaps_with: &[&DeconstructedPat<Self>],
) {
}
}
@ -140,7 +140,7 @@ fn lint_overlapping_range_endpoints(
/// The arm of a match expression.
#[derive(Debug)]
pub struct MatchArm<'p, Cx: TypeCx> {
pub pat: &'p DeconstructedPat<'p, Cx>,
pub pat: &'p DeconstructedPat<Cx>,
pub has_guard: bool,
pub arm_data: Cx::ArmData,
}

32
compiler/rustc_pattern_analysis/src/pat.rs
View file

@ -6,7 +6,7 @@
use smallvec::{smallvec, SmallVec};
use crate::constructor::{Constructor, Slice, SliceKind};
use crate::{Captures, TypeCx};
use crate::TypeCx;
use self::Constructor::*;
@ -21,9 +21,9 @@
/// 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: TypeCx> {
pub struct DeconstructedPat<Cx: TypeCx> {
ctor: Constructor<Cx>,
fields: &'p [DeconstructedPat<'p, Cx>],
fields: Vec<DeconstructedPat<Cx>>,
ty: Cx::Ty,
/// Extra data to store in a pattern. `None` if the pattern is a wildcard that does not
/// correspond to a user-supplied pattern.
@ -32,14 +32,20 @@ pub struct DeconstructedPat<'p, Cx: TypeCx> {
useful: Cell<bool>,
}
impl<'p, Cx: TypeCx> DeconstructedPat<'p, Cx> {
impl<Cx: TypeCx> DeconstructedPat<Cx> {
pub fn wildcard(ty: Cx::Ty) -> Self {
DeconstructedPat { ctor: Wildcard, fields: &[], ty, data: None, useful: Cell::new(false) }
DeconstructedPat {
ctor: Wildcard,
fields: Vec::new(),
ty,
data: None,
useful: Cell::new(false),
}
}
pub fn new(
ctor: Constructor<Cx>,
fields: &'p [DeconstructedPat<'p, Cx>],
fields: Vec<DeconstructedPat<Cx>>,
ty: Cx::Ty,
data: Cx::PatData,
) -> Self {
@ -62,17 +68,17 @@ pub fn data(&self) -> Option<&Cx::PatData> {
self.data.as_ref()
}
pub fn iter_fields(&self) -> impl Iterator<Item = &'p DeconstructedPat<'p, Cx>> + Captures<'_> {
pub fn iter_fields<'a>(&'a self) -> impl Iterator<Item = &'a DeconstructedPat<Cx>> {
self.fields.iter()
}
/// Specialize this pattern with a constructor.
/// `other_ctor` can be different from `self.ctor`, but must be covered by it.
pub(crate) fn specialize(
&self,
pub(crate) fn specialize<'a>(
&'a self,
other_ctor: &Constructor<Cx>,
ctor_arity: usize,
) -> SmallVec<[PatOrWild<'p, Cx>; 2]> {
) -> SmallVec<[PatOrWild<'a, Cx>; 2]> {
let wildcard_sub_tys = || (0..ctor_arity).map(|_| PatOrWild::Wild).collect();
match (&self.ctor, other_ctor) {
// Return a wildcard for each field of `other_ctor`.
@ -139,7 +145,7 @@ fn collect_redundant_subpatterns<'a>(&'a self, subpats: &mut Vec<&'a Self>) {
}
/// This is best effort and not good enough for a `Display` impl.
impl<'p, Cx: TypeCx> fmt::Debug for DeconstructedPat<'p, Cx> {
impl<Cx: TypeCx> fmt::Debug for DeconstructedPat<Cx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let pat = self;
let mut first = true;
@ -221,7 +227,7 @@ pub(crate) enum PatOrWild<'p, Cx: TypeCx> {
/// A non-user-provided wildcard, created during specialization.
Wild,
/// A user-provided pattern.
Pat(&'p DeconstructedPat<'p, Cx>),
Pat(&'p DeconstructedPat<Cx>),
}
impl<'p, Cx: TypeCx> Clone for PatOrWild<'p, Cx> {
@ -236,7 +242,7 @@ fn clone(&self) -> Self {
impl<'p, Cx: TypeCx> Copy for PatOrWild<'p, Cx> {}
impl<'p, Cx: TypeCx> PatOrWild<'p, Cx> {
pub(crate) fn as_pat(&self) -> Option<&'p DeconstructedPat<'p, Cx>> {
pub(crate) fn as_pat(&self) -> Option<&'p DeconstructedPat<Cx>> {
match self {
PatOrWild::Wild => None,
PatOrWild::Pat(pat) => Some(pat),

4
compiler/rustc_pattern_analysis/src/pat_column.rs
View file

@ -13,7 +13,7 @@
#[derive(Debug)]
pub struct PatternColumn<'p, Cx: TypeCx> {
/// This must not contain an or-pattern. `expand_and_push` takes care to expand them.
patterns: Vec<&'p DeconstructedPat<'p, Cx>>,
patterns: Vec<&'p DeconstructedPat<Cx>>,
}
impl<'p, Cx: TypeCx> PatternColumn<'p, Cx> {
@ -41,7 +41,7 @@ fn expand_and_push(&mut self, pat: PatOrWild<'p, Cx>) {
pub fn head_ty(&self) -> Option<&Cx::Ty> {
self.patterns.first().map(|pat| pat.ty())
}
pub fn iter<'a>(&'a self) -> impl Iterator<Item = &'p DeconstructedPat<'p, Cx>> + Captures<'a> {
pub fn iter<'a>(&'a self) -> impl Iterator<Item = &'p DeconstructedPat<Cx>> + Captures<'a> {
self.patterns.iter().copied()
}

69
compiler/rustc_pattern_analysis/src/rustc.rs
View file

@ -1,8 +1,7 @@
use smallvec::SmallVec;
use std::fmt;
use std::iter::once;
use rustc_arena::{DroplessArena, TypedArena};
use rustc_arena::DroplessArena;
use rustc_hir::def_id::DefId;
use rustc_hir::HirId;
use rustc_index::{Idx, IndexVec};
@ -27,8 +26,7 @@
pub type Constructor<'p, 'tcx> = crate::constructor::Constructor<RustcMatchCheckCtxt<'p, 'tcx>>;
pub type ConstructorSet<'p, 'tcx> =
crate::constructor::ConstructorSet<RustcMatchCheckCtxt<'p, 'tcx>>;
pub type DeconstructedPat<'p, 'tcx> =
crate::pat::DeconstructedPat<'p, RustcMatchCheckCtxt<'p, 'tcx>>;
pub type DeconstructedPat<'p, 'tcx> = crate::pat::DeconstructedPat<RustcMatchCheckCtxt<'p, 'tcx>>;
pub type MatchArm<'p, 'tcx> = crate::MatchArm<'p, RustcMatchCheckCtxt<'p, 'tcx>>;
pub type Usefulness<'p, 'tcx> = crate::usefulness::Usefulness<'p, RustcMatchCheckCtxt<'p, 'tcx>>;
pub type UsefulnessReport<'p, 'tcx> =
@ -64,7 +62,7 @@ pub fn inner(self) -> Ty<'tcx> {
}
#[derive(Clone)]
pub struct RustcMatchCheckCtxt<'p, 'tcx> {
pub struct RustcMatchCheckCtxt<'p, 'tcx: 'p> {
pub tcx: TyCtxt<'tcx>,
pub typeck_results: &'tcx ty::TypeckResults<'tcx>,
/// The module in which the match occurs. This is necessary for
@ -74,8 +72,6 @@ pub struct RustcMatchCheckCtxt<'p, 'tcx> {
/// outside its module and should not be matchable with an empty match statement.
pub module: DefId,
pub param_env: ty::ParamEnv<'tcx>,
/// To allocate lowered patterns
pub pattern_arena: &'p TypedArena<DeconstructedPat<'p, 'tcx>>,
/// To allocate the result of `self.ctor_sub_tys()`
pub dropless_arena: &'p DroplessArena,
/// Lint level at the match.
@ -91,13 +87,13 @@ pub struct RustcMatchCheckCtxt<'p, 'tcx> {
pub known_valid_scrutinee: bool,
}
impl<'p, 'tcx> fmt::Debug for RustcMatchCheckCtxt<'p, 'tcx> {
impl<'p, 'tcx: 'p> fmt::Debug for RustcMatchCheckCtxt<'p, 'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("RustcMatchCheckCtxt").finish()
}
}
impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> {
impl<'p, 'tcx: 'p> RustcMatchCheckCtxt<'p, 'tcx> {
/// Type inference occasionally gives us opaque types in places where corresponding patterns
/// have more specific types. To avoid inconsistencies as well as detect opaque uninhabited
/// types, we use the corresponding concrete type if possible.
@ -459,21 +455,20 @@ pub(crate) fn lower_pat_range_bdy(
/// Note: the input patterns must have been lowered through
/// `rustc_mir_build::thir::pattern::check_match::MatchVisitor::lower_pattern`.
pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
let singleton = |pat| std::slice::from_ref(self.pattern_arena.alloc(pat));
let cx = self;
let ty = cx.reveal_opaque_ty(pat.ty);
let ctor;
let fields: &[_];
let mut fields: Vec<_>;
match &pat.kind {
PatKind::AscribeUserType { subpattern, .. }
| PatKind::InlineConstant { subpattern, .. } => return self.lower_pat(subpattern),
PatKind::Binding { subpattern: Some(subpat), .. } => return self.lower_pat(subpat),
PatKind::Binding { subpattern: None, .. } | PatKind::Wild => {
ctor = Wildcard;
fields = &[];
fields = vec![];
}
PatKind::Deref { subpattern } => {
fields = singleton(self.lower_pat(subpattern));
fields = vec![self.lower_pat(subpattern)];
ctor = match ty.kind() {
// This is a box pattern.
ty::Adt(adt, ..) if adt.is_box() => Struct,
@ -485,15 +480,14 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
match ty.kind() {
ty::Tuple(fs) => {
ctor = Struct;
let mut wilds: SmallVec<[_; 2]> = fs
fields = fs
.iter()
.map(|ty| cx.reveal_opaque_ty(ty))
.map(|ty| DeconstructedPat::wildcard(ty))
.collect();
for pat in subpatterns {
wilds[pat.field.index()] = self.lower_pat(&pat.pattern);
fields[pat.field.index()] = self.lower_pat(&pat.pattern);
}
fields = cx.pattern_arena.alloc_from_iter(wilds);
}
ty::Adt(adt, args) if adt.is_box() => {
// The only legal patterns of type `Box` (outside `std`) are `_` and box
@ -515,7 +509,7 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
DeconstructedPat::wildcard(self.reveal_opaque_ty(args.type_at(0)))
};
ctor = Struct;
fields = singleton(pat);
fields = vec![pat];
}
ty::Adt(adt, _) => {
ctor = match pat.kind {
@ -535,14 +529,12 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
ty
},
);
let mut wilds: SmallVec<[_; 2]> =
tys.map(|ty| DeconstructedPat::wildcard(ty)).collect();
fields = tys.map(|ty| DeconstructedPat::wildcard(ty)).collect();
for pat in subpatterns {
if let Some(i) = field_id_to_id[pat.field.index()] {
wilds[i] = self.lower_pat(&pat.pattern);
fields[i] = self.lower_pat(&pat.pattern);
}
}
fields = cx.pattern_arena.alloc_from_iter(wilds);
}
_ => bug!("pattern has unexpected type: pat: {:?}, ty: {:?}", pat, ty),
}
@ -554,7 +546,7 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
Some(b) => Bool(b),
None => Opaque(OpaqueId::new()),
};
fields = &[];
fields = vec![];
}
ty::Char | ty::Int(_) | ty::Uint(_) => {
ctor = match value.try_eval_bits(cx.tcx, cx.param_env) {
@ -570,7 +562,7 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
}
None => Opaque(OpaqueId::new()),
};
fields = &[];
fields = vec![];
}
ty::Float(ty::FloatTy::F32) => {
ctor = match value.try_eval_bits(cx.tcx, cx.param_env) {
@ -581,7 +573,7 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
}
None => Opaque(OpaqueId::new()),
};
fields = &[];
fields = vec![];
}
ty::Float(ty::FloatTy::F64) => {
ctor = match value.try_eval_bits(cx.tcx, cx.param_env) {
@ -592,7 +584,7 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
}
None => Opaque(OpaqueId::new()),
};
fields = &[];
fields = vec![];
}
ty::Ref(_, t, _) if t.is_str() => {
// We want a `&str` constant to behave like a `Deref` pattern, to be compatible
@ -603,16 +595,16 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
// subfields.
// Note: `t` is `str`, not `&str`.
let ty = self.reveal_opaque_ty(*t);
let subpattern = DeconstructedPat::new(Str(*value), &[], ty, pat);
let subpattern = DeconstructedPat::new(Str(*value), Vec::new(), ty, pat);
ctor = Ref;
fields = singleton(subpattern)
fields = vec![subpattern]
}
// All constants that can be structurally matched have already been expanded
// into the corresponding `Pat`s by `const_to_pat`. Constants that remain are
// opaque.
_ => {
ctor = Opaque(OpaqueId::new());
fields = &[];
fields = vec![];
}
}
}
@ -649,7 +641,7 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
}
_ => bug!("invalid type for range pattern: {}", ty.inner()),
};
fields = &[];
fields = vec![];
}
PatKind::Array { prefix, slice, suffix } | PatKind::Slice { prefix, slice, suffix } => {
let array_len = match ty.kind() {
@ -665,26 +657,23 @@ pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> {
SliceKind::FixedLen(prefix.len() + suffix.len())
};
ctor = Slice(Slice::new(array_len, kind));
fields = cx.pattern_arena.alloc_from_iter(
prefix.iter().chain(suffix.iter()).map(|p| self.lower_pat(&*p)),
)
fields = prefix.iter().chain(suffix.iter()).map(|p| self.lower_pat(&*p)).collect();
}
PatKind::Or { .. } => {
ctor = Or;
let pats = expand_or_pat(pat);
fields =
cx.pattern_arena.alloc_from_iter(pats.into_iter().map(|p| self.lower_pat(p)))
fields = pats.into_iter().map(|p| self.lower_pat(p)).collect();
}
PatKind::Never => {
// A never pattern matches all the values of its type (namely none). Moreover it
// must be compatible with other constructors, since we can use `!` on a type like
// `Result<!, !>` which has other constructors. Hence we lower it as a wildcard.
ctor = Wildcard;
fields = &[];
fields = vec![];
}
PatKind::Error(_) => {
ctor = Opaque(OpaqueId::new());
fields = &[];
fields = vec![];
}
}
DeconstructedPat::new(ctor, fields, ty, pat)
@ -855,7 +844,7 @@ pub fn hoist_witness_pat(&self, pat: &WitnessPat<'p, 'tcx>) -> Pat<'tcx> {
}
}
impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> {
impl<'p, 'tcx: 'p> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> {
type Ty = RevealedTy<'tcx>;
type Error = ErrorGuaranteed;
type VariantIdx = VariantIdx;
@ -889,7 +878,7 @@ fn ctors_for_ty(
fn write_variant_name(
f: &mut fmt::Formatter<'_>,
pat: &crate::pat::DeconstructedPat<'_, Self>,
pat: &crate::pat::DeconstructedPat<Self>,
) -> fmt::Result {
if let ty::Adt(adt, _) = pat.ty().kind() {
if adt.is_box() {
@ -908,9 +897,9 @@ fn bug(&self, fmt: fmt::Arguments<'_>) -> Self::Error {
fn lint_overlapping_range_endpoints(
&self,
pat: &crate::pat::DeconstructedPat<'_, Self>,
pat: &crate::pat::DeconstructedPat<Self>,
overlaps_on: IntRange,
overlaps_with: &[&crate::pat::DeconstructedPat<'_, Self>],
overlaps_with: &[&crate::pat::DeconstructedPat<Self>],
) {
let overlap_as_pat = self.hoist_pat_range(&overlaps_on, *pat.ty());
let overlaps: Vec<_> = overlaps_with

4
compiler/rustc_pattern_analysis/src/usefulness.rs
View file

@ -848,7 +848,7 @@ fn clone(&self) -> Self {
}
impl<'p, Cx: TypeCx> PatStack<'p, Cx> {
fn from_pattern(pat: &'p DeconstructedPat<'p, Cx>) -> Self {
fn from_pattern(pat: &'p DeconstructedPat<Cx>) -> Self {
PatStack { pats: smallvec![PatOrWild::Pat(pat)], relevant: true }
}
@ -1575,7 +1575,7 @@ 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.
Useful(Vec<&'p DeconstructedPat<'p, Cx>>),
Useful(Vec<&'p DeconstructedPat<Cx>>),
/// The arm is redundant and can be removed without changing the behavior of the match
/// expression.
Redundant,