diff --git a/Cargo.lock b/Cargo.lock
index ef6b0a5959f8c..4eafda94037c3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -65,6 +65,12 @@ dependencies = [
"rand_xorshift",
]
+[[package]]
+name = "allocator-api2"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4f263788a35611fba42eb41ff811c5d0360c58b97402570312a350736e2542e"
+
[[package]]
name = "ammonia"
version = "3.2.0"
@@ -1522,6 +1528,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "33ff8ae62cd3a9102e5637afc8452c55acf3844001bd5374e0b0bd7b6616c038"
dependencies = [
"ahash 0.8.2",
+]
+
+[[package]]
+name = "hashbrown"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c6201b9ff9fd90a5a3bac2e56a830d0caa509576f0e503818ee82c181b3437a"
+dependencies = [
+ "allocator-api2",
"compiler_builtins",
"rustc-std-workspace-alloc",
"rustc-std-workspace-core",
@@ -4633,7 +4648,7 @@ dependencies = [
"core",
"dlmalloc",
"fortanix-sgx-abi",
- "hashbrown 0.13.1",
+ "hashbrown 0.14.0",
"hermit-abi 0.3.0",
"libc",
"miniz_oxide",
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 7a297ea0d5f82..24d1cc8af82f5 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -4,7 +4,7 @@
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![feature(array_windows)]
-#![feature(drain_filter)]
+#![feature(extract_if)]
#![feature(if_let_guard)]
#![feature(let_chains)]
#![feature(never_type)]
@@ -1399,7 +1399,7 @@ impl HandlerInner {
!self.emitted_diagnostics.insert(diagnostic_hash)
};
- diagnostic.children.drain_filter(already_emitted_sub).for_each(|_| {});
+ diagnostic.children.extract_if(already_emitted_sub).for_each(|_| {});
self.emitter.emit_diagnostic(diagnostic);
if diagnostic.is_error() {
diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index 5cd2cd50c113c..d2a1b1c1a428e 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -59,8 +59,6 @@ This API is completely unstable and subject to change.
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![feature(box_patterns)]
#![feature(control_flow_enum)]
-#![feature(drain_filter)]
-#![feature(hash_drain_filter)]
#![feature(if_let_guard)]
#![feature(is_sorted)]
#![feature(iter_intersperse)]
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index 4a3e28ffce95b..bf8ad5faac482 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -753,20 +753,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
return;
}
- errors.drain_filter(|error| {
+ errors.retain(|error| {
let Error::Invalid(
provided_idx,
expected_idx,
Compatibility::Incompatible(Some(e)),
- ) = error else { return false };
+ ) = error else { return true };
let (provided_ty, provided_span) = provided_arg_tys[*provided_idx];
let trace =
mk_trace(provided_span, formal_and_expected_inputs[*expected_idx], provided_ty);
if !matches!(trace.cause.as_failure_code(*e), FailureCode::Error0308) {
self.err_ctxt().report_and_explain_type_error(trace, *e).emit();
- return true;
+ return false;
}
- false
+ true
});
// We're done if we found errors, but we already emitted them.
diff --git a/compiler/rustc_hir_typeck/src/lib.rs b/compiler/rustc_hir_typeck/src/lib.rs
index b97b55d8f7ee8..7a897778ff7af 100644
--- a/compiler/rustc_hir_typeck/src/lib.rs
+++ b/compiler/rustc_hir_typeck/src/lib.rs
@@ -5,7 +5,6 @@
#![feature(box_patterns)]
#![feature(min_specialization)]
#![feature(control_flow_enum)]
-#![feature(drain_filter)]
#![feature(option_as_slice)]
#![allow(rustc::potential_query_instability)]
#![recursion_limit = "256"]
diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
index 9f664d0f0c8e2..87373d9974357 100644
--- a/compiler/rustc_metadata/src/lib.rs
+++ b/compiler/rustc_metadata/src/lib.rs
@@ -1,6 +1,6 @@
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![feature(decl_macro)]
-#![feature(drain_filter)]
+#![feature(extract_if)]
#![feature(generators)]
#![feature(iter_from_generator)]
#![feature(let_chains)]
diff --git a/compiler/rustc_metadata/src/native_libs.rs b/compiler/rustc_metadata/src/native_libs.rs
index c83c47e722bf0..0dd7b11979168 100644
--- a/compiler/rustc_metadata/src/native_libs.rs
+++ b/compiler/rustc_metadata/src/native_libs.rs
@@ -425,7 +425,7 @@ impl<'tcx> Collector<'tcx> {
// can move them to the end of the list below.
let mut existing = self
.libs
- .drain_filter(|lib| {
+ .extract_if(|lib| {
if lib.name.as_str() == passed_lib.name {
// FIXME: This whole logic is questionable, whether modifiers are
// involved or not, library reordering and kind overriding without
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index 0d6c2eba06c89..1b125e8e26dbc 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -54,7 +54,7 @@
#![feature(try_reserve_kind)]
#![feature(nonzero_ops)]
#![feature(decl_macro)]
-#![feature(drain_filter)]
+#![feature(extract_if)]
#![feature(intra_doc_pointers)]
#![feature(yeet_expr)]
#![feature(result_option_inspect)]
diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs
index 9c91b7784032d..9c948dba1e438 100644
--- a/compiler/rustc_middle/src/ty/diagnostics.rs
+++ b/compiler/rustc_middle/src/ty/diagnostics.rs
@@ -237,7 +237,7 @@ pub fn suggest_constraining_type_params<'a>(
{
let mut sized_constraints =
- constraints.drain_filter(|(_, def_id)| *def_id == tcx.lang_items().sized_trait());
+ constraints.extract_if(|(_, def_id)| *def_id == tcx.lang_items().sized_trait());
if let Some((constraint, def_id)) = sized_constraints.next() {
applicability = Applicability::MaybeIncorrect;
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 7d9f6c38e36a4..9c8c0ea0be004 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -2,7 +2,6 @@
#![deny(rustc::untranslatable_diagnostic)]
#![deny(rustc::diagnostic_outside_of_impl)]
#![feature(box_patterns)]
-#![feature(drain_filter)]
#![feature(is_sorted)]
#![feature(let_chains)]
#![feature(map_try_insert)]
diff --git a/compiler/rustc_mir_transform/src/sroa.rs b/compiler/rustc_mir_transform/src/sroa.rs
index e4b3b8b926213..881a1547c5245 100644
--- a/compiler/rustc_mir_transform/src/sroa.rs
+++ b/compiler/rustc_mir_transform/src/sroa.rs
@@ -436,13 +436,12 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
VarDebugInfoContents::Composite { ty: _, ref mut fragments } => {
let mut new_fragments = Vec::new();
debug!(?fragments);
- fragments
- .drain_filter(|fragment| {
- if let Some(repl) =
+ fragments.retain_mut(|fragment| {
+ if let Some(repl) =
self.replacements.replace_place(self.tcx, fragment.contents.as_ref())
{
fragment.contents = repl;
- false
+ true
} else if let Some(local) = fragment.contents.as_local()
&& let Some(frg) = self.gather_debug_info_fragments(local)
{
@@ -450,12 +449,11 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
f.projection.splice(0..0, fragment.projection.iter().copied());
f
}));
- true
- } else {
false
+ } else {
+ true
}
- })
- .for_each(drop);
+ });
debug!(?fragments);
debug!(?new_fragments);
fragments.extend(new_fragments);
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index ca811c9ed7d98..e42b2df1a5ab8 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -2494,7 +2494,7 @@ fn show_candidates(
for path_strings in [&mut accessible_path_strings, &mut inaccessible_path_strings] {
path_strings.sort_by(|a, b| a.0.cmp(&b.0));
let core_path_strings =
- path_strings.drain_filter(|p| p.0.starts_with("core::")).collect::<Vec<_>>();
+ path_strings.extract_if(|p| p.0.starts_with("core::")).collect::<Vec<_>>();
path_strings.extend(core_path_strings);
path_strings.dedup_by(|a, b| a.0 == b.0);
}
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 2f9759a668bbe..e4b01ef2b1710 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -496,7 +496,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
// Try to filter out intrinsics candidates, as long as we have
// some other candidates to suggest.
let intrinsic_candidates: Vec<_> = candidates
- .drain_filter(|sugg| {
+ .extract_if(|sugg| {
let path = path_names_to_string(&sugg.path);
path.starts_with("core::intrinsics::") || path.starts_with("std::intrinsics::")
})
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index db97039b907c4..82b333fee28b8 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -9,7 +9,7 @@
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![feature(assert_matches)]
#![feature(box_patterns)]
-#![feature(drain_filter)]
+#![feature(extract_if)]
#![feature(if_let_guard)]
#![feature(iter_intersperse)]
#![feature(let_chains)]
diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs
index ed3994be98796..56d37d58de752 100644
--- a/compiler/rustc_trait_selection/src/lib.rs
+++ b/compiler/rustc_trait_selection/src/lib.rs
@@ -14,8 +14,7 @@
#![feature(associated_type_bounds)]
#![feature(box_patterns)]
#![feature(control_flow_enum)]
-#![feature(drain_filter)]
-#![feature(hash_drain_filter)]
+#![feature(extract_if)]
#![feature(let_chains)]
#![feature(if_let_guard)]
#![feature(never_type)]
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index c2f94cb638566..37d27fcee7c4f 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -354,7 +354,7 @@ pub fn normalize_param_env_or_error<'tcx>(
// This works fairly well because trait matching does not actually care about param-env
// TypeOutlives predicates - these are normally used by regionck.
let outlives_predicates: Vec<_> = predicates
- .drain_filter(|predicate| {
+ .extract_if(|predicate| {
matches!(
predicate.kind().skip_binder(),
ty::PredicateKind::Clause(ty::Clause::TypeOutlives(..))
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 563cc257e0349..0a1e971f268e3 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -1170,11 +1170,11 @@ fn opt_normalize_projection_type<'a, 'b, 'tcx>(
};
let mut deduped: SsoHashSet<_> = Default::default();
- result.obligations.drain_filter(|projected_obligation| {
+ result.obligations.retain(|projected_obligation| {
if !deduped.insert(projected_obligation.clone()) {
- return true;
+ return false;
}
- false
+ true
});
if use_cache {
diff --git a/compiler/rustc_traits/src/lib.rs b/compiler/rustc_traits/src/lib.rs
index 907e2d39c518f..590d0bd0e42e1 100644
--- a/compiler/rustc_traits/src/lib.rs
+++ b/compiler/rustc_traits/src/lib.rs
@@ -4,7 +4,6 @@
#![deny(rustc::untranslatable_diagnostic)]
#![deny(rustc::diagnostic_outside_of_impl)]
#![feature(let_chains)]
-#![feature(drain_filter)]
#![recursion_limit = "256"]
#[macro_use]
diff --git a/library/alloc/benches/btree/map.rs b/library/alloc/benches/btree/map.rs
index ec1b0a8eba039..7d236647750d0 100644
--- a/library/alloc/benches/btree/map.rs
+++ b/library/alloc/benches/btree/map.rs
@@ -385,7 +385,7 @@ pub fn clone_slim_100_and_clear(b: &mut Bencher) {
#[bench]
pub fn clone_slim_100_and_drain_all(b: &mut Bencher) {
let src = slim_map(100);
- b.iter(|| src.clone().drain_filter(|_, _| true).count())
+ b.iter(|| src.clone().extract_if(|_, _| true).count())
}
#[bench]
@@ -393,7 +393,7 @@ pub fn clone_slim_100_and_drain_half(b: &mut Bencher) {
let src = slim_map(100);
b.iter(|| {
let mut map = src.clone();
- assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 100 / 2);
+ assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 100 / 2);
assert_eq!(map.len(), 100 / 2);
})
}
@@ -456,7 +456,7 @@ pub fn clone_slim_10k_and_clear(b: &mut Bencher) {
#[bench]
pub fn clone_slim_10k_and_drain_all(b: &mut Bencher) {
let src = slim_map(10_000);
- b.iter(|| src.clone().drain_filter(|_, _| true).count())
+ b.iter(|| src.clone().extract_if(|_, _| true).count())
}
#[bench]
@@ -464,7 +464,7 @@ pub fn clone_slim_10k_and_drain_half(b: &mut Bencher) {
let src = slim_map(10_000);
b.iter(|| {
let mut map = src.clone();
- assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 10_000 / 2);
+ assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 10_000 / 2);
assert_eq!(map.len(), 10_000 / 2);
})
}
@@ -527,7 +527,7 @@ pub fn clone_fat_val_100_and_clear(b: &mut Bencher) {
#[bench]
pub fn clone_fat_val_100_and_drain_all(b: &mut Bencher) {
let src = fat_val_map(100);
- b.iter(|| src.clone().drain_filter(|_, _| true).count())
+ b.iter(|| src.clone().extract_if(|_, _| true).count())
}
#[bench]
@@ -535,7 +535,7 @@ pub fn clone_fat_val_100_and_drain_half(b: &mut Bencher) {
let src = fat_val_map(100);
b.iter(|| {
let mut map = src.clone();
- assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 100 / 2);
+ assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 100 / 2);
assert_eq!(map.len(), 100 / 2);
})
}
diff --git a/library/alloc/benches/btree/set.rs b/library/alloc/benches/btree/set.rs
index 3f4b0e0f14af7..09d72c7206469 100644
--- a/library/alloc/benches/btree/set.rs
+++ b/library/alloc/benches/btree/set.rs
@@ -69,7 +69,7 @@ pub fn clone_100_and_clear(b: &mut Bencher) {
#[bench]
pub fn clone_100_and_drain_all(b: &mut Bencher) {
let src = slim_set(100);
- b.iter(|| src.clone().drain_filter(|_| true).count())
+ b.iter(|| src.clone().extract_if(|_| true).count())
}
#[bench]
@@ -77,7 +77,7 @@ pub fn clone_100_and_drain_half(b: &mut Bencher) {
let src = slim_set(100);
b.iter(|| {
let mut set = src.clone();
- assert_eq!(set.drain_filter(|i| i % 2 == 0).count(), 100 / 2);
+ assert_eq!(set.extract_if(|i| i % 2 == 0).count(), 100 / 2);
assert_eq!(set.len(), 100 / 2);
})
}
@@ -140,7 +140,7 @@ pub fn clone_10k_and_clear(b: &mut Bencher) {
#[bench]
pub fn clone_10k_and_drain_all(b: &mut Bencher) {
let src = slim_set(10_000);
- b.iter(|| src.clone().drain_filter(|_| true).count())
+ b.iter(|| src.clone().extract_if(|_| true).count())
}
#[bench]
@@ -148,7 +148,7 @@ pub fn clone_10k_and_drain_half(b: &mut Bencher) {
let src = slim_set(10_000);
b.iter(|| {
let mut set = src.clone();
- assert_eq!(set.drain_filter(|i| i % 2 == 0).count(), 10_000 / 2);
+ assert_eq!(set.extract_if(|i| i % 2 == 0).count(), 10_000 / 2);
assert_eq!(set.len(), 10_000 / 2);
})
}
diff --git a/library/alloc/benches/lib.rs b/library/alloc/benches/lib.rs
index b25d63d835b54..638f343fb244b 100644
--- a/library/alloc/benches/lib.rs
+++ b/library/alloc/benches/lib.rs
@@ -1,7 +1,7 @@
// Disabling on android for the time being
// See https://github.com/rust-lang/rust/issues/73535#event-3477699747
#![cfg(not(target_os = "android"))]
-#![feature(btree_drain_filter)]
+#![feature(btree_extract_if)]
#![feature(iter_next_chunk)]
#![feature(repr_simd)]
#![feature(slice_partition_dedup)]
diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index 1f8a1ecba6e67..ff908ec12ec86 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -1132,7 +1132,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
K: Ord,
F: FnMut(&K, &mut V) -> bool,
{
- self.drain_filter(|k, v| !f(k, v));
+ self.extract_if(|k, v| !f(k, v)).for_each(drop);
}
/// Moves all elements from `other` into `self`, leaving `other` empty.
@@ -1395,40 +1395,37 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
/// The iterator also lets you mutate the value of each element in the
/// closure, regardless of whether you choose to keep or remove it.
///
- /// If the iterator is only partially consumed or not consumed at all, each
- /// of the remaining elements is still subjected to the closure, which may
- /// change its value and, by returning `true`, have the element removed and
- /// dropped.
+ /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
+ /// or the iteration short-circuits, then the remaining elements will be retained.
+ /// Use [`retain`] with a negated predicate if you do not need the returned iterator.
///
- /// It is unspecified how many more elements will be subjected to the
- /// closure if a panic occurs in the closure, or a panic occurs while
- /// dropping an element, or if the `DrainFilter` value is leaked.
+ /// [`retain`]: BTreeMap::retain
///
/// # Examples
///
/// Splitting a map into even and odd keys, reusing the original map:
///
/// ```
- /// #![feature(btree_drain_filter)]
+ /// #![feature(btree_extract_if)]
/// use std::collections::BTreeMap;
///
/// let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
- /// let evens: BTreeMap<_, _> = map.drain_filter(|k, _v| k % 2 == 0).collect();
+ /// let evens: BTreeMap<_, _> = map.extract_if(|k, _v| k % 2 == 0).collect();
/// let odds = map;
/// assert_eq!(evens.keys().copied().collect::<Vec<_>>(), [0, 2, 4, 6]);
/// assert_eq!(odds.keys().copied().collect::<Vec<_>>(), [1, 3, 5, 7]);
/// ```
- #[unstable(feature = "btree_drain_filter", issue = "70530")]
- pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, K, V, F, A>
+ #[unstable(feature = "btree_extract_if", issue = "70530")]
+ pub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, K, V, F, A>
where
K: Ord,
F: FnMut(&K, &mut V) -> bool,
{
- let (inner, alloc) = self.drain_filter_inner();
- DrainFilter { pred, inner, alloc }
+ let (inner, alloc) = self.extract_if_inner();
+ ExtractIf { pred, inner, alloc }
}
- pub(super) fn drain_filter_inner(&mut self) -> (DrainFilterInner<'_, K, V>, A)
+ pub(super) fn extract_if_inner(&mut self) -> (ExtractIfInner<'_, K, V>, A)
where
K: Ord,
{
@@ -1436,7 +1433,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
let (root, dormant_root) = DormantMutRef::new(root);
let front = root.borrow_mut().first_leaf_edge();
(
- DrainFilterInner {
+ ExtractIfInner {
length: &mut self.length,
dormant_root: Some(dormant_root),
cur_leaf_edge: Some(front),
@@ -1445,7 +1442,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
)
} else {
(
- DrainFilterInner {
+ ExtractIfInner {
length: &mut self.length,
dormant_root: None,
cur_leaf_edge: None,
@@ -1899,9 +1896,10 @@ impl<K, V> Default for Values<'_, K, V> {
}
}
-/// An iterator produced by calling `drain_filter` on BTreeMap.
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-pub struct DrainFilter<
+/// An iterator produced by calling `extract_if` on BTreeMap.
+#[unstable(feature = "btree_extract_if", issue = "70530")]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+pub struct ExtractIf<
'a,
K,
V,
@@ -1911,13 +1909,13 @@ pub struct DrainFilter<
F: 'a + FnMut(&K, &mut V) -> bool,
{
pred: F,
- inner: DrainFilterInner<'a, K, V>,
+ inner: ExtractIfInner<'a, K, V>,
/// The BTreeMap will outlive this IntoIter so we don't care about drop order for `alloc`.
alloc: A,
}
-/// Most of the implementation of DrainFilter are generic over the type
-/// of the predicate, thus also serving for BTreeSet::DrainFilter.
-pub(super) struct DrainFilterInner<'a, K, V> {
+/// Most of the implementation of ExtractIf are generic over the type
+/// of the predicate, thus also serving for BTreeSet::ExtractIf.
+pub(super) struct ExtractIfInner<'a, K, V> {
/// Reference to the length field in the borrowed map, updated live.
length: &'a mut usize,
/// Buried reference to the root field in the borrowed map.
@@ -1929,30 +1927,20 @@ pub(super) struct DrainFilterInner<'a, K, V> {
cur_leaf_edge: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>>,
}
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-impl<K, V, F, A: Allocator + Clone> Drop for DrainFilter<'_, K, V, F, A>
-where
- F: FnMut(&K, &mut V) -> bool,
-{
- fn drop(&mut self) {
- self.for_each(drop);
- }
-}
-
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-impl<K, V, F> fmt::Debug for DrainFilter<'_, K, V, F>
+#[unstable(feature = "btree_extract_if", issue = "70530")]
+impl<K, V, F> fmt::Debug for ExtractIf<'_, K, V, F>
where
K: fmt::Debug,
V: fmt::Debug,
F: FnMut(&K, &mut V) -> bool,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- f.debug_tuple("DrainFilter").field(&self.inner.peek()).finish()
+ f.debug_tuple("ExtractIf").field(&self.inner.peek()).finish()
}
}
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-impl<K, V, F, A: Allocator + Clone> Iterator for DrainFilter<'_, K, V, F, A>
+#[unstable(feature = "btree_extract_if", issue = "70530")]
+impl<K, V, F, A: Allocator + Clone> Iterator for ExtractIf<'_, K, V, F, A>
where
F: FnMut(&K, &mut V) -> bool,
{
@@ -1967,14 +1955,14 @@ where
}
}
-impl<'a, K, V> DrainFilterInner<'a, K, V> {
+impl<'a, K, V> ExtractIfInner<'a, K, V> {
/// Allow Debug implementations to predict the next element.
pub(super) fn peek(&self) -> Option<(&K, &V)> {
let edge = self.cur_leaf_edge.as_ref()?;
edge.reborrow().next_kv().ok().map(Handle::into_kv)
}
- /// Implementation of a typical `DrainFilter::next` method, given the predicate.
+ /// Implementation of a typical `ExtractIf::next` method, given the predicate.
pub(super) fn next<F, A: Allocator + Clone>(&mut self, pred: &mut F, alloc: A) -> Option<(K, V)>
where
F: FnMut(&K, &mut V) -> bool,
@@ -2001,7 +1989,7 @@ impl<'a, K, V> DrainFilterInner<'a, K, V> {
None
}
- /// Implementation of a typical `DrainFilter::size_hint` method.
+ /// Implementation of a typical `ExtractIf::size_hint` method.
pub(super) fn size_hint(&self) -> (usize, Option<usize>) {
// In most of the btree iterators, `self.length` is the number of elements
// yet to be visited. Here, it includes elements that were visited and that
@@ -2011,8 +1999,8 @@ impl<'a, K, V> DrainFilterInner<'a, K, V> {
}
}
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-impl<K, V, F> FusedIterator for DrainFilter<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {}
+#[unstable(feature = "btree_extract_if", issue = "70530")]
+impl<K, V, F> FusedIterator for ExtractIf<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {}
#[stable(feature = "btree_range", since = "1.17.0")]
impl<'a, K, V> Iterator for Range<'a, K, V> {
diff --git a/library/alloc/src/collections/btree/map/tests.rs b/library/alloc/src/collections/btree/map/tests.rs
index 8efd9a03ad09f..8681cfcd61757 100644
--- a/library/alloc/src/collections/btree/map/tests.rs
+++ b/library/alloc/src/collections/btree/map/tests.rs
@@ -941,13 +941,13 @@ fn test_retain() {
assert_eq!(map[&6], 60);
}
-mod test_drain_filter {
+mod test_extract_if {
use super::*;
#[test]
fn empty() {
let mut map: BTreeMap<i32, i32> = BTreeMap::new();
- map.drain_filter(|_, _| unreachable!("there's nothing to decide on"));
+ map.extract_if(|_, _| unreachable!("there's nothing to decide on")).for_each(drop);
assert_eq!(map.height(), None);
map.check();
}
@@ -957,7 +957,7 @@ mod test_drain_filter {
fn consumed_keeping_all() {
let pairs = (0..3).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
- assert!(map.drain_filter(|_, _| false).eq(iter::empty()));
+ assert!(map.extract_if(|_, _| false).eq(iter::empty()));
map.check();
}
@@ -966,7 +966,7 @@ mod test_drain_filter {
fn consumed_removing_all() {
let pairs = (0..3).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs.clone());
- assert!(map.drain_filter(|_, _| true).eq(pairs));
+ assert!(map.extract_if(|_, _| true).eq(pairs));
assert!(map.is_empty());
map.check();
}
@@ -977,7 +977,7 @@ mod test_drain_filter {
let pairs = (0..3).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
assert!(
- map.drain_filter(|_, v| {
+ map.extract_if(|_, v| {
*v += 6;
false
})
@@ -994,7 +994,7 @@ mod test_drain_filter {
let pairs = (0..3).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
assert!(
- map.drain_filter(|_, v| {
+ map.extract_if(|_, v| {
*v += 6;
true
})
@@ -1008,7 +1008,7 @@ mod test_drain_filter {
fn underfull_keeping_all() {
let pairs = (0..3).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
- map.drain_filter(|_, _| false);
+ map.extract_if(|_, _| false).for_each(drop);
assert!(map.keys().copied().eq(0..3));
map.check();
}
@@ -1018,7 +1018,7 @@ mod test_drain_filter {
let pairs = (0..3).map(|i| (i, i));
for doomed in 0..3 {
let mut map = BTreeMap::from_iter(pairs.clone());
- map.drain_filter(|i, _| *i == doomed);
+ map.extract_if(|i, _| *i == doomed).for_each(drop);
assert_eq!(map.len(), 2);
map.check();
}
@@ -1029,7 +1029,7 @@ mod test_drain_filter {
let pairs = (0..3).map(|i| (i, i));
for sacred in 0..3 {
let mut map = BTreeMap::from_iter(pairs.clone());
- map.drain_filter(|i, _| *i != sacred);
+ map.extract_if(|i, _| *i != sacred).for_each(drop);
assert!(map.keys().copied().eq(sacred..=sacred));
map.check();
}
@@ -1039,7 +1039,7 @@ mod test_drain_filter {
fn underfull_removing_all() {
let pairs = (0..3).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
- map.drain_filter(|_, _| true);
+ map.extract_if(|_, _| true).for_each(drop);
assert!(map.is_empty());
map.check();
}
@@ -1048,7 +1048,7 @@ mod test_drain_filter {
fn height_0_keeping_all() {
let pairs = (0..node::CAPACITY).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
- map.drain_filter(|_, _| false);
+ map.extract_if(|_, _| false).for_each(drop);
assert!(map.keys().copied().eq(0..node::CAPACITY));
map.check();
}
@@ -1058,7 +1058,7 @@ mod test_drain_filter {
let pairs = (0..node::CAPACITY).map(|i| (i, i));
for doomed in 0..node::CAPACITY {
let mut map = BTreeMap::from_iter(pairs.clone());
- map.drain_filter(|i, _| *i == doomed);
+ map.extract_if(|i, _| *i == doomed).for_each(drop);
assert_eq!(map.len(), node::CAPACITY - 1);
map.check();
}
@@ -1069,7 +1069,7 @@ mod test_drain_filter {
let pairs = (0..node::CAPACITY).map(|i| (i, i));
for sacred in 0..node::CAPACITY {
let mut map = BTreeMap::from_iter(pairs.clone());
- map.drain_filter(|i, _| *i != sacred);
+ map.extract_if(|i, _| *i != sacred).for_each(drop);
assert!(map.keys().copied().eq(sacred..=sacred));
map.check();
}
@@ -1079,7 +1079,7 @@ mod test_drain_filter {
fn height_0_removing_all() {
let pairs = (0..node::CAPACITY).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
- map.drain_filter(|_, _| true);
+ map.extract_if(|_, _| true).for_each(drop);
assert!(map.is_empty());
map.check();
}
@@ -1087,7 +1087,7 @@ mod test_drain_filter {
#[test]
fn height_0_keeping_half() {
let mut map = BTreeMap::from_iter((0..16).map(|i| (i, i)));
- assert_eq!(map.drain_filter(|i, _| *i % 2 == 0).count(), 8);
+ assert_eq!(map.extract_if(|i, _| *i % 2 == 0).count(), 8);
assert_eq!(map.len(), 8);
map.check();
}
@@ -1096,7 +1096,7 @@ mod test_drain_filter {
fn height_1_removing_all() {
let pairs = (0..MIN_INSERTS_HEIGHT_1).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
- map.drain_filter(|_, _| true);
+ map.extract_if(|_, _| true).for_each(drop);
assert!(map.is_empty());
map.check();
}
@@ -1106,7 +1106,7 @@ mod test_drain_filter {
let pairs = (0..MIN_INSERTS_HEIGHT_1).map(|i| (i, i));
for doomed in 0..MIN_INSERTS_HEIGHT_1 {
let mut map = BTreeMap::from_iter(pairs.clone());
- map.drain_filter(|i, _| *i == doomed);
+ map.extract_if(|i, _| *i == doomed).for_each(drop);
assert_eq!(map.len(), MIN_INSERTS_HEIGHT_1 - 1);
map.check();
}
@@ -1117,7 +1117,7 @@ mod test_drain_filter {
let pairs = (0..MIN_INSERTS_HEIGHT_1).map(|i| (i, i));
for sacred in 0..MIN_INSERTS_HEIGHT_1 {
let mut map = BTreeMap::from_iter(pairs.clone());
- map.drain_filter(|i, _| *i != sacred);
+ map.extract_if(|i, _| *i != sacred).for_each(drop);
assert!(map.keys().copied().eq(sacred..=sacred));
map.check();
}
@@ -1128,7 +1128,7 @@ mod test_drain_filter {
let pairs = (0..MIN_INSERTS_HEIGHT_2).map(|i| (i, i));
for doomed in (0..MIN_INSERTS_HEIGHT_2).step_by(12) {
let mut map = BTreeMap::from_iter(pairs.clone());
- map.drain_filter(|i, _| *i == doomed);
+ map.extract_if(|i, _| *i == doomed).for_each(drop);
assert_eq!(map.len(), MIN_INSERTS_HEIGHT_2 - 1);
map.check();
}
@@ -1139,7 +1139,7 @@ mod test_drain_filter {
let pairs = (0..MIN_INSERTS_HEIGHT_2).map(|i| (i, i));
for sacred in (0..MIN_INSERTS_HEIGHT_2).step_by(12) {
let mut map = BTreeMap::from_iter(pairs.clone());
- map.drain_filter(|i, _| *i != sacred);
+ map.extract_if(|i, _| *i != sacred).for_each(drop);
assert!(map.keys().copied().eq(sacred..=sacred));
map.check();
}
@@ -1149,7 +1149,7 @@ mod test_drain_filter {
fn height_2_removing_all() {
let pairs = (0..MIN_INSERTS_HEIGHT_2).map(|i| (i, i));
let mut map = BTreeMap::from_iter(pairs);
- map.drain_filter(|_, _| true);
+ map.extract_if(|_, _| true).for_each(drop);
assert!(map.is_empty());
map.check();
}
@@ -1165,7 +1165,8 @@ mod test_drain_filter {
map.insert(b.spawn(Panic::InDrop), ());
map.insert(c.spawn(Panic::Never), ());
- catch_unwind(move || drop(map.drain_filter(|dummy, _| dummy.query(true)))).unwrap_err();
+ catch_unwind(move || map.extract_if(|dummy, _| dummy.query(true)).for_each(drop))
+ .unwrap_err();
assert_eq!(a.queried(), 1);
assert_eq!(b.queried(), 1);
@@ -1186,8 +1187,10 @@ mod test_drain_filter {
map.insert(b.spawn(Panic::InQuery), ());
map.insert(c.spawn(Panic::InQuery), ());
- catch_unwind(AssertUnwindSafe(|| drop(map.drain_filter(|dummy, _| dummy.query(true)))))
- .unwrap_err();
+ catch_unwind(AssertUnwindSafe(|| {
+ map.extract_if(|dummy, _| dummy.query(true)).for_each(drop)
+ }))
+ .unwrap_err();
assert_eq!(a.queried(), 1);
assert_eq!(b.queried(), 1);
@@ -1214,7 +1217,7 @@ mod test_drain_filter {
map.insert(c.spawn(Panic::InQuery), ());
{
- let mut it = map.drain_filter(|dummy, _| dummy.query(true));
+ let mut it = map.extract_if(|dummy, _| dummy.query(true));
catch_unwind(AssertUnwindSafe(|| while it.next().is_some() {})).unwrap_err();
// Iterator behaviour after a panic is explicitly unspecified,
// so this is just the current implementation:
@@ -1657,8 +1660,8 @@ fn assert_sync() {
v.into_values()
}
- fn drain_filter<T: Sync + Ord>(v: &mut BTreeMap<T, T>) -> impl Sync + '_ {
- v.drain_filter(|_, _| false)
+ fn extract_if<T: Sync + Ord>(v: &mut BTreeMap<T, T>) -> impl Sync + '_ {
+ v.extract_if(|_, _| false)
}
fn iter<T: Sync>(v: &BTreeMap<T, T>) -> impl Sync + '_ {
@@ -1726,8 +1729,8 @@ fn assert_send() {
v.into_values()
}
- fn drain_filter<T: Send + Ord>(v: &mut BTreeMap<T, T>) -> impl Send + '_ {
- v.drain_filter(|_, _| false)
+ fn extract_if<T: Send + Ord>(v: &mut BTreeMap<T, T>) -> impl Send + '_ {
+ v.extract_if(|_, _| false)
}
fn iter<T: Send + Sync>(v: &BTreeMap<T, T>) -> impl Send + '_ {
diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index 940fa30afb80f..c4461040b20d7 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -999,7 +999,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
T: Ord,
F: FnMut(&T) -> bool,
{
- self.drain_filter(|v| !f(v));
+ self.extract_if(|v| !f(v)).for_each(drop);
}
/// Moves all elements from `other` into `self`, leaving `other` empty.
@@ -1084,36 +1084,33 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
/// yielded. If the closure returns `false`, or panics, the element remains
/// in the set and will not be yielded.
///
- /// If the iterator is only partially consumed or not consumed at all, each
- /// of the remaining elements is still subjected to the closure and removed
- /// and dropped if it returns `true`.
- ///
- /// It is unspecified how many more elements will be subjected to the
- /// closure if a panic occurs in the closure, or if a panic occurs while
- /// dropping an element, or if the `DrainFilter` itself is leaked.
+ /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
+ /// or the iteration short-circuits, then the remaining elements will be retained.
+ /// Use [`retain`] with a negated predicate if you do not need the returned iterator.
///
+ /// [`retain`]: BTreeSet::retain
/// # Examples
///
/// Splitting a set into even and odd values, reusing the original set:
///
/// ```
- /// #![feature(btree_drain_filter)]
+ /// #![feature(btree_extract_if)]
/// use std::collections::BTreeSet;
///
/// let mut set: BTreeSet<i32> = (0..8).collect();
- /// let evens: BTreeSet<_> = set.drain_filter(|v| v % 2 == 0).collect();
+ /// let evens: BTreeSet<_> = set.extract_if(|v| v % 2 == 0).collect();
/// let odds = set;
/// assert_eq!(evens.into_iter().collect::<Vec<_>>(), vec![0, 2, 4, 6]);
/// assert_eq!(odds.into_iter().collect::<Vec<_>>(), vec![1, 3, 5, 7]);
/// ```
- #[unstable(feature = "btree_drain_filter", issue = "70530")]
- pub fn drain_filter<'a, F>(&'a mut self, pred: F) -> DrainFilter<'a, T, F, A>
+ #[unstable(feature = "btree_extract_if", issue = "70530")]
+ pub fn extract_if<'a, F>(&'a mut self, pred: F) -> ExtractIf<'a, T, F, A>
where
T: Ord,
F: 'a + FnMut(&T) -> bool,
{
- let (inner, alloc) = self.map.drain_filter_inner();
- DrainFilter { pred, inner, alloc }
+ let (inner, alloc) = self.map.extract_if_inner();
+ ExtractIf { pred, inner, alloc }
}
/// Gets an iterator that visits the elements in the `BTreeSet` in ascending
@@ -1275,9 +1272,10 @@ impl<'a, T, A: Allocator + Clone> IntoIterator for &'a BTreeSet<T, A> {
}
}
-/// An iterator produced by calling `drain_filter` on BTreeSet.
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-pub struct DrainFilter<
+/// An iterator produced by calling `extract_if` on BTreeSet.
+#[unstable(feature = "btree_extract_if", issue = "70530")]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+pub struct ExtractIf<
'a,
T,
F,
@@ -1287,34 +1285,24 @@ pub struct DrainFilter<
F: 'a + FnMut(&T) -> bool,
{
pred: F,
- inner: super::map::DrainFilterInner<'a, T, SetValZST>,
+ inner: super::map::ExtractIfInner<'a, T, SetValZST>,
/// The BTreeMap will outlive this IntoIter so we don't care about drop order for `alloc`.
alloc: A,
}
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-impl<T, F, A: Allocator + Clone> Drop for DrainFilter<'_, T, F, A>
-where
- F: FnMut(&T) -> bool,
-{
- fn drop(&mut self) {
- self.for_each(drop);
- }
-}
-
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-impl<T, F, A: Allocator + Clone> fmt::Debug for DrainFilter<'_, T, F, A>
+#[unstable(feature = "btree_extract_if", issue = "70530")]
+impl<T, F, A: Allocator + Clone> fmt::Debug for ExtractIf<'_, T, F, A>
where
T: fmt::Debug,
F: FnMut(&T) -> bool,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- f.debug_tuple("DrainFilter").field(&self.inner.peek().map(|(k, _)| k)).finish()
+ f.debug_tuple("ExtractIf").field(&self.inner.peek().map(|(k, _)| k)).finish()
}
}
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-impl<'a, T, F, A: Allocator + Clone> Iterator for DrainFilter<'_, T, F, A>
+#[unstable(feature = "btree_extract_if", issue = "70530")]
+impl<'a, T, F, A: Allocator + Clone> Iterator for ExtractIf<'_, T, F, A>
where
F: 'a + FnMut(&T) -> bool,
{
@@ -1331,11 +1319,8 @@ where
}
}
-#[unstable(feature = "btree_drain_filter", issue = "70530")]
-impl<T, F, A: Allocator + Clone> FusedIterator for DrainFilter<'_, T, F, A> where
- F: FnMut(&T) -> bool
-{
-}
+#[unstable(feature = "btree_extract_if", issue = "70530")]
+impl<T, F, A: Allocator + Clone> FusedIterator for ExtractIf<'_, T, F, A> where F: FnMut(&T) -> bool {}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T: Ord, A: Allocator + Clone> Extend<T> for BTreeSet<T, A> {
diff --git a/library/alloc/src/collections/btree/set/tests.rs b/library/alloc/src/collections/btree/set/tests.rs
index 8eb730f4aaffc..e05bf0e20036d 100644
--- a/library/alloc/src/collections/btree/set/tests.rs
+++ b/library/alloc/src/collections/btree/set/tests.rs
@@ -366,19 +366,19 @@ fn test_retain() {
}
#[test]
-fn test_drain_filter() {
+fn test_extract_if() {
let mut x = BTreeSet::from([1]);
let mut y = BTreeSet::from([1]);
- x.drain_filter(|_| true);
- y.drain_filter(|_| false);
+ x.extract_if(|_| true).for_each(drop);
+ y.extract_if(|_| false).for_each(drop);
assert_eq!(x.len(), 0);
assert_eq!(y.len(), 1);
}
#[test]
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
-fn test_drain_filter_drop_panic_leak() {
+fn test_extract_if_drop_panic_leak() {
let a = CrashTestDummy::new(0);
let b = CrashTestDummy::new(1);
let c = CrashTestDummy::new(2);
@@ -387,7 +387,7 @@ fn test_drain_filter_drop_panic_leak() {
set.insert(b.spawn(Panic::InDrop));
set.insert(c.spawn(Panic::Never));
- catch_unwind(move || drop(set.drain_filter(|dummy| dummy.query(true)))).ok();
+ catch_unwind(move || set.extract_if(|dummy| dummy.query(true)).for_each(drop)).ok();
assert_eq!(a.queried(), 1);
assert_eq!(b.queried(), 1);
@@ -399,7 +399,7 @@ fn test_drain_filter_drop_panic_leak() {
#[test]
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
-fn test_drain_filter_pred_panic_leak() {
+fn test_extract_if_pred_panic_leak() {
let a = CrashTestDummy::new(0);
let b = CrashTestDummy::new(1);
let c = CrashTestDummy::new(2);
@@ -408,7 +408,8 @@ fn test_drain_filter_pred_panic_leak() {
set.insert(b.spawn(Panic::InQuery));
set.insert(c.spawn(Panic::InQuery));
- catch_unwind(AssertUnwindSafe(|| drop(set.drain_filter(|dummy| dummy.query(true))))).ok();
+ catch_unwind(AssertUnwindSafe(|| set.extract_if(|dummy| dummy.query(true)).for_each(drop)))
+ .ok();
assert_eq!(a.queried(), 1);
assert_eq!(b.queried(), 1);
@@ -605,8 +606,8 @@ fn assert_sync() {
v.range(..)
}
- fn drain_filter<T: Sync + Ord>(v: &mut BTreeSet<T>) -> impl Sync + '_ {
- v.drain_filter(|_| false)
+ fn extract_if<T: Sync + Ord>(v: &mut BTreeSet<T>) -> impl Sync + '_ {
+ v.extract_if(|_| false)
}
fn difference<T: Sync + Ord>(v: &BTreeSet<T>) -> impl Sync + '_ {
@@ -644,8 +645,8 @@ fn assert_send() {
v.range(..)
}
- fn drain_filter<T: Send + Ord>(v: &mut BTreeSet<T>) -> impl Send + '_ {
- v.drain_filter(|_| false)
+ fn extract_if<T: Send + Ord>(v: &mut BTreeSet<T>) -> impl Send + '_ {
+ v.extract_if(|_| false)
}
fn difference<T: Send + Sync + Ord>(v: &BTreeSet<T>) -> impl Send + '_ {
diff --git a/library/alloc/src/collections/linked_list.rs b/library/alloc/src/collections/linked_list.rs
index 4cd34ac2fa74f..052edf453f679 100644
--- a/library/alloc/src/collections/linked_list.rs
+++ b/library/alloc/src/collections/linked_list.rs
@@ -1030,7 +1030,11 @@ impl<T, A: Allocator> LinkedList<T, A> {
/// If the closure returns false, the element will remain in the list and will not be yielded
/// by the iterator.
///
- /// Note that `drain_filter` lets you mutate every element in the filter closure, regardless of
+ /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
+ /// or the iteration short-circuits, then the remaining elements will be retained.
+ /// Use `extract_if().for_each(drop)` if you do not need the returned iterator.
+ ///
+ /// Note that `extract_if` lets you mutate every element in the filter closure, regardless of
/// whether you choose to keep or remove it.
///
/// # Examples
@@ -1038,20 +1042,20 @@ impl<T, A: Allocator> LinkedList<T, A> {
/// Splitting a list into evens and odds, reusing the original list:
///
/// ```
- /// #![feature(drain_filter)]
+ /// #![feature(extract_if)]
/// use std::collections::LinkedList;
///
/// let mut numbers: LinkedList<u32> = LinkedList::new();
/// numbers.extend(&[1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15]);
///
- /// let evens = numbers.drain_filter(|x| *x % 2 == 0).collect::<LinkedList<_>>();
+ /// let evens = numbers.extract_if(|x| *x % 2 == 0).collect::<LinkedList<_>>();
/// let odds = numbers;
///
/// assert_eq!(evens.into_iter().collect::<Vec<_>>(), vec![2, 4, 6, 8, 14]);
/// assert_eq!(odds.into_iter().collect::<Vec<_>>(), vec![1, 3, 5, 9, 11, 13, 15]);
/// ```
- #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
- pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<'_, T, F, A>
+ #[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+ pub fn extract_if<F>(&mut self, filter: F) -> ExtractIf<'_, T, F, A>
where
F: FnMut(&mut T) -> bool,
{
@@ -1059,7 +1063,7 @@ impl<T, A: Allocator> LinkedList<T, A> {
let it = self.head;
let old_len = self.len;
- DrainFilter { list: self, it, pred: filter, idx: 0, old_len }
+ ExtractIf { list: self, it, pred: filter, idx: 0, old_len }
}
}
@@ -1803,9 +1807,10 @@ impl<'a, T, A: Allocator> CursorMut<'a, T, A> {
}
}
-/// An iterator produced by calling `drain_filter` on LinkedList.
-#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-pub struct DrainFilter<
+/// An iterator produced by calling `extract_if` on LinkedList.
+#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+pub struct ExtractIf<
'a,
T: 'a,
F: 'a,
@@ -1820,8 +1825,8 @@ pub struct DrainFilter<
old_len: usize,
}
-#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<T, F, A: Allocator> Iterator for DrainFilter<'_, T, F, A>
+#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+impl<T, F, A: Allocator> Iterator for ExtractIf<'_, T, F, A>
where
F: FnMut(&mut T) -> bool,
{
@@ -1849,40 +1854,13 @@ where
}
}
-#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<T, F, A: Allocator> Drop for DrainFilter<'_, T, F, A>
-where
- F: FnMut(&mut T) -> bool,
-{
- fn drop(&mut self) {
- struct DropGuard<'r, 'a, T, F, A: Allocator>(&'r mut DrainFilter<'a, T, F, A>)
- where
- F: FnMut(&mut T) -> bool;
-
- impl<'r, 'a, T, F, A: Allocator> Drop for DropGuard<'r, 'a, T, F, A>
- where
- F: FnMut(&mut T) -> bool,
- {
- fn drop(&mut self) {
- self.0.for_each(drop);
- }
- }
-
- while let Some(item) = self.next() {
- let guard = DropGuard(self);
- drop(item);
- mem::forget(guard);
- }
- }
-}
-
-#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<T: fmt::Debug, F> fmt::Debug for DrainFilter<'_, T, F>
+#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+impl<T: fmt::Debug, F> fmt::Debug for ExtractIf<'_, T, F>
where
F: FnMut(&mut T) -> bool,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- f.debug_tuple("DrainFilter").field(&self.list).finish()
+ f.debug_tuple("ExtractIf").field(&self.list).finish()
}
}
diff --git a/library/alloc/src/collections/linked_list/tests.rs b/library/alloc/src/collections/linked_list/tests.rs
index 6a0ea61836217..8dcd59d12d927 100644
--- a/library/alloc/src/collections/linked_list/tests.rs
+++ b/library/alloc/src/collections/linked_list/tests.rs
@@ -540,10 +540,10 @@ fn test_show() {
}
#[test]
-fn drain_filter_test() {
+fn extract_if_test() {
let mut m: LinkedList<u32> = LinkedList::new();
m.extend(&[1, 2, 3, 4, 5, 6]);
- let deleted = m.drain_filter(|v| *v < 4).collect::<Vec<_>>();
+ let deleted = m.extract_if(|v| *v < 4).collect::<Vec<_>>();
check_links(&m);
@@ -555,7 +555,7 @@ fn drain_filter_test() {
fn drain_to_empty_test() {
let mut m: LinkedList<u32> = LinkedList::new();
m.extend(&[1, 2, 3, 4, 5, 6]);
- let deleted = m.drain_filter(|_| true).collect::<Vec<_>>();
+ let deleted = m.extract_if(|_| true).collect::<Vec<_>>();
check_links(&m);
@@ -811,11 +811,11 @@ fn test_contains() {
}
#[test]
-fn drain_filter_empty() {
+fn extract_if_empty() {
let mut list: LinkedList<i32> = LinkedList::new();
{
- let mut iter = list.drain_filter(|_| true);
+ let mut iter = list.extract_if(|_| true);
assert_eq!(iter.size_hint(), (0, Some(0)));
assert_eq!(iter.next(), None);
assert_eq!(iter.size_hint(), (0, Some(0)));
@@ -828,13 +828,13 @@ fn drain_filter_empty() {
}
#[test]
-fn drain_filter_zst() {
+fn extract_if_zst() {
let mut list: LinkedList<_> = [(), (), (), (), ()].into_iter().collect();
let initial_len = list.len();
let mut count = 0;
{
- let mut iter = list.drain_filter(|_| true);
+ let mut iter = list.extract_if(|_| true);
assert_eq!(iter.size_hint(), (0, Some(initial_len)));
while let Some(_) = iter.next() {
count += 1;
@@ -851,14 +851,14 @@ fn drain_filter_zst() {
}
#[test]
-fn drain_filter_false() {
+fn extract_if_false() {
let mut list: LinkedList<_> = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].into_iter().collect();
let initial_len = list.len();
let mut count = 0;
{
- let mut iter = list.drain_filter(|_| false);
+ let mut iter = list.extract_if(|_| false);
assert_eq!(iter.size_hint(), (0, Some(initial_len)));
for _ in iter.by_ref() {
count += 1;
@@ -874,14 +874,14 @@ fn drain_filter_false() {
}
#[test]
-fn drain_filter_true() {
+fn extract_if_true() {
let mut list: LinkedList<_> = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].into_iter().collect();
let initial_len = list.len();
let mut count = 0;
{
- let mut iter = list.drain_filter(|_| true);
+ let mut iter = list.extract_if(|_| true);
assert_eq!(iter.size_hint(), (0, Some(initial_len)));
while let Some(_) = iter.next() {
count += 1;
@@ -898,7 +898,7 @@ fn drain_filter_true() {
}
#[test]
-fn drain_filter_complex() {
+fn extract_if_complex() {
{
// [+xxx++++++xxxxx++++x+x++]
let mut list = [
@@ -908,7 +908,7 @@ fn drain_filter_complex() {
.into_iter()
.collect::<LinkedList<_>>();
- let removed = list.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = list.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
@@ -926,7 +926,7 @@ fn drain_filter_complex() {
.into_iter()
.collect::<LinkedList<_>>();
- let removed = list.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = list.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
@@ -944,7 +944,7 @@ fn drain_filter_complex() {
.into_iter()
.collect::<LinkedList<_>>();
- let removed = list.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = list.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
@@ -961,7 +961,7 @@ fn drain_filter_complex() {
.into_iter()
.collect::<LinkedList<_>>();
- let removed = list.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = list.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]);
@@ -975,7 +975,7 @@ fn drain_filter_complex() {
.into_iter()
.collect::<LinkedList<_>>();
- let removed = list.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = list.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]);
@@ -986,7 +986,7 @@ fn drain_filter_complex() {
#[test]
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
-fn drain_filter_drop_panic_leak() {
+fn extract_if_drop_panic_leak() {
let d0 = CrashTestDummy::new(0);
let d1 = CrashTestDummy::new(1);
let d2 = CrashTestDummy::new(2);
@@ -1005,22 +1005,28 @@ fn drain_filter_drop_panic_leak() {
q.push_front(d1.spawn(Panic::InDrop));
q.push_front(d0.spawn(Panic::Never));
- catch_unwind(AssertUnwindSafe(|| drop(q.drain_filter(|_| true)))).unwrap_err();
+ catch_unwind(AssertUnwindSafe(|| q.extract_if(|_| true).for_each(drop))).unwrap_err();
assert_eq!(d0.dropped(), 1);
assert_eq!(d1.dropped(), 1);
+ assert_eq!(d2.dropped(), 0);
+ assert_eq!(d3.dropped(), 0);
+ assert_eq!(d4.dropped(), 0);
+ assert_eq!(d5.dropped(), 0);
+ assert_eq!(d6.dropped(), 0);
+ assert_eq!(d7.dropped(), 0);
+ drop(q);
assert_eq!(d2.dropped(), 1);
assert_eq!(d3.dropped(), 1);
assert_eq!(d4.dropped(), 1);
assert_eq!(d5.dropped(), 1);
assert_eq!(d6.dropped(), 1);
assert_eq!(d7.dropped(), 1);
- assert!(q.is_empty());
}
#[test]
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
-fn drain_filter_pred_panic_leak() {
+fn extract_if_pred_panic_leak() {
static mut DROPS: i32 = 0;
#[derive(Debug)]
@@ -1045,7 +1051,7 @@ fn drain_filter_pred_panic_leak() {
q.push_front(D(0));
catch_unwind(AssertUnwindSafe(|| {
- drop(q.drain_filter(|item| if item.0 >= 2 { panic!() } else { true }))
+ q.extract_if(|item| if item.0 >= 2 { panic!() } else { true }).for_each(drop)
}))
.ok();
diff --git a/library/alloc/src/vec/drain_filter.rs b/library/alloc/src/vec/drain_filter.rs
deleted file mode 100644
index 21b0902346206..0000000000000
--- a/library/alloc/src/vec/drain_filter.rs
+++ /dev/null
@@ -1,197 +0,0 @@
-use crate::alloc::{Allocator, Global};
-use core::mem::{ManuallyDrop, SizedTypeProperties};
-use core::ptr;
-use core::slice;
-
-use super::Vec;
-
-/// An iterator which uses a closure to determine if an element should be removed.
-///
-/// This struct is created by [`Vec::drain_filter`].
-/// See its documentation for more.
-///
-/// # Example
-///
-/// ```
-/// #![feature(drain_filter)]
-///
-/// let mut v = vec![0, 1, 2];
-/// let iter: std::vec::DrainFilter<'_, _, _> = v.drain_filter(|x| *x % 2 == 0);
-/// ```
-#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-#[derive(Debug)]
-pub struct DrainFilter<
- 'a,
- T,
- F,
- #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
-> where
- F: FnMut(&mut T) -> bool,
-{
- pub(super) vec: &'a mut Vec<T, A>,
- /// The index of the item that will be inspected by the next call to `next`.
- pub(super) idx: usize,
- /// The number of items that have been drained (removed) thus far.
- pub(super) del: usize,
- /// The original length of `vec` prior to draining.
- pub(super) old_len: usize,
- /// The filter test predicate.
- pub(super) pred: F,
- /// A flag that indicates a panic has occurred in the filter test predicate.
- /// This is used as a hint in the drop implementation to prevent consumption
- /// of the remainder of the `DrainFilter`. Any unprocessed items will be
- /// backshifted in the `vec`, but no further items will be dropped or
- /// tested by the filter predicate.
- pub(super) panic_flag: bool,
-}
-
-impl<T, F, A: Allocator> DrainFilter<'_, T, F, A>
-where
- F: FnMut(&mut T) -> bool,
-{
- /// Returns a reference to the underlying allocator.
- #[unstable(feature = "allocator_api", issue = "32838")]
- #[inline]
- pub fn allocator(&self) -> &A {
- self.vec.allocator()
- }
-
- /// Keep unyielded elements in the source `Vec`.
- ///
- /// # Examples
- ///
- /// ```
- /// #![feature(drain_filter)]
- /// #![feature(drain_keep_rest)]
- ///
- /// let mut vec = vec!['a', 'b', 'c'];
- /// let mut drain = vec.drain_filter(|_| true);
- ///
- /// assert_eq!(drain.next().unwrap(), 'a');
- ///
- /// // This call keeps 'b' and 'c' in the vec.
- /// drain.keep_rest();
- ///
- /// // If we wouldn't call `keep_rest()`,
- /// // `vec` would be empty.
- /// assert_eq!(vec, ['b', 'c']);
- /// ```
- #[unstable(feature = "drain_keep_rest", issue = "101122")]
- pub fn keep_rest(self) {
- // At this moment layout looks like this:
- //
- // _____________________/-- old_len
- // / \
- // [kept] [yielded] [tail]
- // \_______/ ^-- idx
- // \-- del
- //
- // Normally `Drop` impl would drop [tail] (via .for_each(drop), ie still calling `pred`)
- //
- // 1. Move [tail] after [kept]
- // 2. Update length of the original vec to `old_len - del`
- // a. In case of ZST, this is the only thing we want to do
- // 3. Do *not* drop self, as everything is put in a consistent state already, there is nothing to do
- let mut this = ManuallyDrop::new(self);
-
- unsafe {
- // ZSTs have no identity, so we don't need to move them around.
- if !T::IS_ZST && this.idx < this.old_len && this.del > 0 {
- let ptr = this.vec.as_mut_ptr();
- let src = ptr.add(this.idx);
- let dst = src.sub(this.del);
- let tail_len = this.old_len - this.idx;
- src.copy_to(dst, tail_len);
- }
-
- let new_len = this.old_len - this.del;
- this.vec.set_len(new_len);
- }
- }
-}
-
-#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<T, F, A: Allocator> Iterator for DrainFilter<'_, T, F, A>
-where
- F: FnMut(&mut T) -> bool,
-{
- type Item = T;
-
- fn next(&mut self) -> Option<T> {
- unsafe {
- while self.idx < self.old_len {
- let i = self.idx;
- let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len);
- self.panic_flag = true;
- let drained = (self.pred)(&mut v[i]);
- self.panic_flag = false;
- // Update the index *after* the predicate is called. If the index
- // is updated prior and the predicate panics, the element at this
- // index would be leaked.
- self.idx += 1;
- if drained {
- self.del += 1;
- return Some(ptr::read(&v[i]));
- } else if self.del > 0 {
- let del = self.del;
- let src: *const T = &v[i];
- let dst: *mut T = &mut v[i - del];
- ptr::copy_nonoverlapping(src, dst, 1);
- }
- }
- None
- }
- }
-
- fn size_hint(&self) -> (usize, Option<usize>) {
- (0, Some(self.old_len - self.idx))
- }
-}
-
-#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<T, F, A: Allocator> Drop for DrainFilter<'_, T, F, A>
-where
- F: FnMut(&mut T) -> bool,
-{
- fn drop(&mut self) {
- struct BackshiftOnDrop<'a, 'b, T, F, A: Allocator>
- where
- F: FnMut(&mut T) -> bool,
- {
- drain: &'b mut DrainFilter<'a, T, F, A>,
- }
-
- impl<'a, 'b, T, F, A: Allocator> Drop for BackshiftOnDrop<'a, 'b, T, F, A>
- where
- F: FnMut(&mut T) -> bool,
- {
- fn drop(&mut self) {
- unsafe {
- if self.drain.idx < self.drain.old_len && self.drain.del > 0 {
- // This is a pretty messed up state, and there isn't really an
- // obviously right thing to do. We don't want to keep trying
- // to execute `pred`, so we just backshift all the unprocessed
- // elements and tell the vec that they still exist. The backshift
- // is required to prevent a double-drop of the last successfully
- // drained item prior to a panic in the predicate.
- let ptr = self.drain.vec.as_mut_ptr();
- let src = ptr.add(self.drain.idx);
- let dst = src.sub(self.drain.del);
- let tail_len = self.drain.old_len - self.drain.idx;
- src.copy_to(dst, tail_len);
- }
- self.drain.vec.set_len(self.drain.old_len - self.drain.del);
- }
- }
- }
-
- let backshift = BackshiftOnDrop { drain: self };
-
- // Attempt to consume any remaining elements if the filter predicate
- // has not yet panicked. We'll backshift any remaining elements
- // whether we've already panicked or if the consumption here panics.
- if !backshift.drain.panic_flag {
- backshift.drain.for_each(drop);
- }
- }
-}
diff --git a/library/alloc/src/vec/extract_if.rs b/library/alloc/src/vec/extract_if.rs
new file mode 100644
index 0000000000000..e8e6bd56d21ba
--- /dev/null
+++ b/library/alloc/src/vec/extract_if.rs
@@ -0,0 +1,121 @@
+use crate::alloc::{Allocator, Global};
+use core::ptr;
+use core::slice;
+
+use super::Vec;
+
+/// An iterator which uses a closure to determine if an element should be removed.
+///
+/// This struct is created by [`Vec::extract_if`].
+/// See its documentation for more.
+///
+/// # Example
+///
+/// ```
+/// #![feature(extract_if)]
+///
+/// let mut v = vec![0, 1, 2];
+/// let iter: std::vec::ExtractIf<'_, _, _> = v.extract_if(|x| *x % 2 == 0);
+/// ```
+#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[derive(Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+pub struct ExtractIf<
+ 'a,
+ T,
+ F,
+ #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
+> where
+ F: FnMut(&mut T) -> bool,
+{
+ pub(super) vec: &'a mut Vec<T, A>,
+ /// The index of the item that will be inspected by the next call to `next`.
+ pub(super) idx: usize,
+ /// The number of items that have been drained (removed) thus far.
+ pub(super) del: usize,
+ /// The original length of `vec` prior to draining.
+ pub(super) old_len: usize,
+ /// The filter test predicate.
+ pub(super) pred: F,
+ /// A flag that indicates a panic has occurred in the filter test predicate.
+ /// This is used as a hint in the drop implementation to prevent consumption
+ /// of the remainder of the `ExtractIf`. Any unprocessed items will be
+ /// backshifted in the `vec`, but no further items will be dropped or
+ /// tested by the filter predicate.
+ pub(super) panic_flag: bool,
+}
+
+impl<T, F, A: Allocator> ExtractIf<'_, T, F, A>
+where
+ F: FnMut(&mut T) -> bool,
+{
+ /// Returns a reference to the underlying allocator.
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[inline]
+ pub fn allocator(&self) -> &A {
+ self.vec.allocator()
+ }
+}
+
+#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+impl<T, F, A: Allocator> Iterator for ExtractIf<'_, T, F, A>
+where
+ F: FnMut(&mut T) -> bool,
+{
+ type Item = T;
+
+ fn next(&mut self) -> Option<T> {
+ unsafe {
+ while self.idx < self.old_len {
+ let i = self.idx;
+ let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len);
+ self.panic_flag = true;
+ let drained = (self.pred)(&mut v[i]);
+ self.panic_flag = false;
+ // Update the index *after* the predicate is called. If the index
+ // is updated prior and the predicate panics, the element at this
+ // index would be leaked.
+ self.idx += 1;
+ if drained {
+ self.del += 1;
+ return Some(ptr::read(&v[i]));
+ } else if self.del > 0 {
+ let del = self.del;
+ let src: *const T = &v[i];
+ let dst: *mut T = &mut v[i - del];
+ ptr::copy_nonoverlapping(src, dst, 1);
+ }
+ }
+ None
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (0, Some(self.old_len - self.idx))
+ }
+}
+
+#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+impl<T, F, A: Allocator> Drop for ExtractIf<'_, T, F, A>
+where
+ F: FnMut(&mut T) -> bool,
+{
+ fn drop(&mut self) {
+ unsafe {
+ if self.idx < self.old_len && self.del > 0 {
+ // This is a pretty messed up state, and there isn't really an
+ // obviously right thing to do. We don't want to keep trying
+ // to execute `pred`, so we just backshift all the unprocessed
+ // elements and tell the vec that they still exist. The backshift
+ // is required to prevent a double-drop of the last successfully
+ // drained item prior to a panic in the predicate.
+ let ptr = self.vec.as_mut_ptr();
+ let src = ptr.add(self.idx);
+ let dst = src.sub(self.del);
+ let tail_len = self.old_len - self.idx;
+ src.copy_to(dst, tail_len);
+ }
+ self.vec.set_len(self.old_len - self.del);
+ }
+ }
+}
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index d89cdff8e366c..289bbc7d2effd 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -71,10 +71,10 @@ use crate::boxed::Box;
use crate::collections::TryReserveError;
use crate::raw_vec::RawVec;
-#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-pub use self::drain_filter::DrainFilter;
+#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+pub use self::extract_if::ExtractIf;
-mod drain_filter;
+mod extract_if;
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "vec_splice", since = "1.21.0")]
@@ -2892,6 +2892,12 @@ impl<T, A: Allocator> Vec<T, A> {
/// If the closure returns false, the element will remain in the vector and will not be yielded
/// by the iterator.
///
+ /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
+ /// or the iteration short-circuits, then the remaining elements will be retained.
+ /// Use [`retain`] with a negated predicate if you do not need the returned iterator.
+ ///
+ /// [`retain`]: Vec::retain
+ ///
/// Using this method is equivalent to the following code:
///
/// ```
@@ -2910,10 +2916,10 @@ impl<T, A: Allocator> Vec<T, A> {
/// # assert_eq!(vec, vec![1, 4, 5]);
/// ```
///
- /// But `drain_filter` is easier to use. `drain_filter` is also more efficient,
+ /// But `extract_if` is easier to use. `extract_if` is also more efficient,
/// because it can backshift the elements of the array in bulk.
///
- /// Note that `drain_filter` also lets you mutate every element in the filter closure,
+ /// Note that `extract_if` also lets you mutate every element in the filter closure,
/// regardless of whether you choose to keep or remove it.
///
/// # Examples
@@ -2921,17 +2927,17 @@ impl<T, A: Allocator> Vec<T, A> {
/// Splitting an array into evens and odds, reusing the original allocation:
///
/// ```
- /// #![feature(drain_filter)]
+ /// #![feature(extract_if)]
/// let mut numbers = vec![1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15];
///
- /// let evens = numbers.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ /// let evens = numbers.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
/// let odds = numbers;
///
/// assert_eq!(evens, vec![2, 4, 6, 8, 14]);
/// assert_eq!(odds, vec![1, 3, 5, 9, 11, 13, 15]);
/// ```
- #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
- pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<'_, T, F, A>
+ #[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+ pub fn extract_if<F>(&mut self, filter: F) -> ExtractIf<'_, T, F, A>
where
F: FnMut(&mut T) -> bool,
{
@@ -2942,7 +2948,7 @@ impl<T, A: Allocator> Vec<T, A> {
self.set_len(0);
}
- DrainFilter { vec: self, idx: 0, del: 0, old_len, pred: filter, panic_flag: false }
+ ExtractIf { vec: self, idx: 0, del: 0, old_len, pred: filter, panic_flag: false }
}
}
diff --git a/library/alloc/tests/autotraits.rs b/library/alloc/tests/autotraits.rs
index 879e32b3fa309..6a8e55bff23d9 100644
--- a/library/alloc/tests/autotraits.rs
+++ b/library/alloc/tests/autotraits.rs
@@ -55,7 +55,7 @@ fn test_btree_map() {
require_send_sync(async {
let _v = None::<
- alloc::collections::btree_map::DrainFilter<
+ alloc::collections::btree_map::ExtractIf<
'_,
&u32,
&u32,
@@ -149,7 +149,7 @@ fn test_btree_set() {
});
require_send_sync(async {
- let _v = None::<alloc::collections::btree_set::DrainFilter<'_, &u32, fn(&&u32) -> bool>>;
+ let _v = None::<alloc::collections::btree_set::ExtractIf<'_, &u32, fn(&&u32) -> bool>>;
async {}.await;
});
@@ -238,7 +238,7 @@ fn test_linked_list() {
/*
require_send_sync(async {
let _v =
- None::<alloc::collections::linked_list::DrainFilter<'_, &u32, fn(&mut &u32) -> bool>>;
+ None::<alloc::collections::linked_list::ExtractIf<'_, &u32, fn(&mut &u32) -> bool>>;
async {}.await;
});
*/
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 0eca4c9bb07aa..aa7a331b368be 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -1,7 +1,7 @@
#![feature(allocator_api)]
#![feature(alloc_layout_extra)]
#![feature(assert_matches)]
-#![feature(btree_drain_filter)]
+#![feature(btree_extract_if)]
#![feature(cow_is_borrowed)]
#![feature(const_cow_is_borrowed)]
#![feature(const_heap)]
@@ -10,7 +10,7 @@
#![feature(const_ptr_write)]
#![feature(const_try)]
#![feature(core_intrinsics)]
-#![feature(drain_filter)]
+#![feature(extract_if)]
#![feature(exact_size_is_empty)]
#![feature(linked_list_cursors)]
#![feature(map_try_insert)]
diff --git a/library/alloc/tests/vec.rs b/library/alloc/tests/vec.rs
index 155431689ec50..21824c8a17c46 100644
--- a/library/alloc/tests/vec.rs
+++ b/library/alloc/tests/vec.rs
@@ -1347,11 +1347,11 @@ fn overaligned_allocations() {
}
#[test]
-fn drain_filter_empty() {
+fn extract_if_empty() {
let mut vec: Vec<i32> = vec![];
{
- let mut iter = vec.drain_filter(|_| true);
+ let mut iter = vec.extract_if(|_| true);
assert_eq!(iter.size_hint(), (0, Some(0)));
assert_eq!(iter.next(), None);
assert_eq!(iter.size_hint(), (0, Some(0)));
@@ -1363,12 +1363,12 @@ fn drain_filter_empty() {
}
#[test]
-fn drain_filter_zst() {
+fn extract_if_zst() {
let mut vec = vec![(), (), (), (), ()];
let initial_len = vec.len();
let mut count = 0;
{
- let mut iter = vec.drain_filter(|_| true);
+ let mut iter = vec.extract_if(|_| true);
assert_eq!(iter.size_hint(), (0, Some(initial_len)));
while let Some(_) = iter.next() {
count += 1;
@@ -1385,13 +1385,13 @@ fn drain_filter_zst() {
}
#[test]
-fn drain_filter_false() {
+fn extract_if_false() {
let mut vec = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
let initial_len = vec.len();
let mut count = 0;
{
- let mut iter = vec.drain_filter(|_| false);
+ let mut iter = vec.extract_if(|_| false);
assert_eq!(iter.size_hint(), (0, Some(initial_len)));
for _ in iter.by_ref() {
count += 1;
@@ -1407,13 +1407,13 @@ fn drain_filter_false() {
}
#[test]
-fn drain_filter_true() {
+fn extract_if_true() {
let mut vec = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
let initial_len = vec.len();
let mut count = 0;
{
- let mut iter = vec.drain_filter(|_| true);
+ let mut iter = vec.extract_if(|_| true);
assert_eq!(iter.size_hint(), (0, Some(initial_len)));
while let Some(_) = iter.next() {
count += 1;
@@ -1430,7 +1430,7 @@ fn drain_filter_true() {
}
#[test]
-fn drain_filter_complex() {
+fn extract_if_complex() {
{
// [+xxx++++++xxxxx++++x+x++]
let mut vec = vec![
@@ -1438,7 +1438,7 @@ fn drain_filter_complex() {
39,
];
- let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = vec.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
@@ -1452,7 +1452,7 @@ fn drain_filter_complex() {
2, 4, 6, 7, 9, 11, 13, 15, 17, 18, 20, 22, 24, 26, 27, 29, 31, 33, 34, 35, 36, 37, 39,
];
- let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = vec.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
@@ -1465,7 +1465,7 @@ fn drain_filter_complex() {
let mut vec =
vec![2, 4, 6, 7, 9, 11, 13, 15, 17, 18, 20, 22, 24, 26, 27, 29, 31, 33, 34, 35, 36];
- let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = vec.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
@@ -1477,7 +1477,7 @@ fn drain_filter_complex() {
// [xxxxxxxxxx+++++++++++]
let mut vec = vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19];
- let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = vec.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]);
@@ -1489,7 +1489,7 @@ fn drain_filter_complex() {
// [+++++++++++xxxxxxxxxx]
let mut vec = vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20];
- let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ let removed = vec.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
assert_eq!(removed.len(), 10);
assert_eq!(removed, vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]);
@@ -1502,7 +1502,7 @@ fn drain_filter_complex() {
#[test]
#[cfg(not(target_os = "emscripten"))]
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
-fn drain_filter_consumed_panic() {
+fn extract_if_consumed_panic() {
use std::rc::Rc;
use std::sync::Mutex;
@@ -1537,9 +1537,9 @@ fn drain_filter_consumed_panic() {
}
c.index < 6
};
- let drain = data.drain_filter(filter);
+ let drain = data.extract_if(filter);
- // NOTE: The DrainFilter is explicitly consumed
+ // NOTE: The ExtractIf is explicitly consumed
drain.for_each(drop);
});
@@ -1555,7 +1555,7 @@ fn drain_filter_consumed_panic() {
#[test]
#[cfg(not(target_os = "emscripten"))]
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
-fn drain_filter_unconsumed_panic() {
+fn extract_if_unconsumed_panic() {
use std::rc::Rc;
use std::sync::Mutex;
@@ -1590,9 +1590,9 @@ fn drain_filter_unconsumed_panic() {
}
c.index < 6
};
- let _drain = data.drain_filter(filter);
+ let _drain = data.extract_if(filter);
- // NOTE: The DrainFilter is dropped without being consumed
+ // NOTE: The ExtractIf is dropped without being consumed
});
let drop_counts = drop_counts.lock().unwrap();
@@ -1604,40 +1604,11 @@ fn drain_filter_unconsumed_panic() {
}
#[test]
-fn drain_filter_unconsumed() {
+fn extract_if_unconsumed() {
let mut vec = vec![1, 2, 3, 4];
- let drain = vec.drain_filter(|&mut x| x % 2 != 0);
+ let drain = vec.extract_if(|&mut x| x % 2 != 0);
drop(drain);
- assert_eq!(vec, [2, 4]);
-}
-
-#[test]
-fn test_drain_filter_keep_rest() {
- let mut v = vec![0, 1, 2, 3, 4, 5, 6];
- let mut drain = v.drain_filter(|&mut x| x % 2 == 0);
- assert_eq!(drain.next(), Some(0));
- assert_eq!(drain.next(), Some(2));
-
- drain.keep_rest();
- assert_eq!(v, &[1, 3, 4, 5, 6]);
-}
-
-#[test]
-fn test_drain_filter_keep_rest_all() {
- let mut v = vec![0, 1, 2, 3, 4, 5, 6];
- v.drain_filter(|_| true).keep_rest();
- assert_eq!(v, &[0, 1, 2, 3, 4, 5, 6]);
-}
-
-#[test]
-fn test_drain_filter_keep_rest_none() {
- let mut v = vec![0, 1, 2, 3, 4, 5, 6];
- let mut drain = v.drain_filter(|_| true);
-
- drain.by_ref().for_each(drop);
-
- drain.keep_rest();
- assert_eq!(v, &[]);
+ assert_eq!(vec, [1, 2, 3, 4]);
}
#[test]
diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
index 4b52894c509da..e6b051838861a 100644
--- a/library/std/Cargo.toml
+++ b/library/std/Cargo.toml
@@ -21,7 +21,7 @@ libc = { version = "0.2.146", default-features = false, features = ['rustc-dep-o
compiler_builtins = { version = "0.1.92" }
profiler_builtins = { path = "../profiler_builtins", optional = true }
unwind = { path = "../unwind" }
-hashbrown = { version = "0.13", default-features = false, features = ['rustc-dep-of-std'] }
+hashbrown = { version = "0.14", default-features = false, features = ['rustc-dep-of-std'] }
std_detect = { path = "../stdarch/crates/std_detect", default-features = false, features = ['rustc-dep-of-std'] }
# Dependencies of the `backtrace` crate
diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs
index c722bad2e4f63..f3316d97c5faf 100644
--- a/library/std/src/collections/hash/map.rs
+++ b/library/std/src/collections/hash/map.rs
@@ -623,28 +623,27 @@ impl<K, V, S> HashMap<K, V, S> {
/// If the closure returns false, or panics, the element remains in the map and will not be
/// yielded.
///
- /// Note that `drain_filter` lets you mutate every value in the filter closure, regardless of
+ /// Note that `extract_if` lets you mutate every value in the filter closure, regardless of
/// whether you choose to keep or remove it.
///
- /// If the iterator is only partially consumed or not consumed at all, each of the remaining
- /// elements will still be subjected to the closure and removed and dropped if it returns true.
+ /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
+ /// or the iteration short-circuits, then the remaining elements will be retained.
+ /// Use [`retain`] with a negated predicate if you do not need the returned iterator.
///
- /// It is unspecified how many more elements will be subjected to the closure
- /// if a panic occurs in the closure, or a panic occurs while dropping an element,
- /// or if the `DrainFilter` value is leaked.
+ /// [`retain`]: HashMap::retain
///
/// # Examples
///
/// Splitting a map into even and odd keys, reusing the original map:
///
/// ```
- /// #![feature(hash_drain_filter)]
+ /// #![feature(hash_extract_if)]
/// use std::collections::HashMap;
///
/// let mut map: HashMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
- /// let drained: HashMap<i32, i32> = map.drain_filter(|k, _v| k % 2 == 0).collect();
+ /// let extracted: HashMap<i32, i32> = map.extract_if(|k, _v| k % 2 == 0).collect();
///
- /// let mut evens = drained.keys().copied().collect::<Vec<_>>();
+ /// let mut evens = extracted.keys().copied().collect::<Vec<_>>();
/// let mut odds = map.keys().copied().collect::<Vec<_>>();
/// evens.sort();
/// odds.sort();
@@ -654,12 +653,12 @@ impl<K, V, S> HashMap<K, V, S> {
/// ```
#[inline]
#[rustc_lint_query_instability]
- #[unstable(feature = "hash_drain_filter", issue = "59618")]
- pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, K, V, F>
+ #[unstable(feature = "hash_extract_if", issue = "59618")]
+ pub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, K, V, F>
where
F: FnMut(&K, &mut V) -> bool,
{
- DrainFilter { base: self.base.drain_filter(pred) }
+ ExtractIf { base: self.base.extract_if(pred) }
}
/// Retains only the elements specified by the predicate.
@@ -1578,28 +1577,29 @@ impl<'a, K, V> Drain<'a, K, V> {
/// A draining, filtering iterator over the entries of a `HashMap`.
///
-/// This `struct` is created by the [`drain_filter`] method on [`HashMap`].
+/// This `struct` is created by the [`extract_if`] method on [`HashMap`].
///
-/// [`drain_filter`]: HashMap::drain_filter
+/// [`extract_if`]: HashMap::extract_if
///
/// # Example
///
/// ```
-/// #![feature(hash_drain_filter)]
+/// #![feature(hash_extract_if)]
///
/// use std::collections::HashMap;
///
/// let mut map = HashMap::from([
/// ("a", 1),
/// ]);
-/// let iter = map.drain_filter(|_k, v| *v % 2 == 0);
+/// let iter = map.extract_if(|_k, v| *v % 2 == 0);
/// ```
-#[unstable(feature = "hash_drain_filter", issue = "59618")]
-pub struct DrainFilter<'a, K, V, F>
+#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+pub struct ExtractIf<'a, K, V, F>
where
F: FnMut(&K, &mut V) -> bool,
{
- base: base::DrainFilter<'a, K, V, F>,
+ base: base::ExtractIf<'a, K, V, F>,
}
/// A mutable iterator over the values of a `HashMap`.
@@ -2479,8 +2479,8 @@ where
}
}
-#[unstable(feature = "hash_drain_filter", issue = "59618")]
-impl<K, V, F> Iterator for DrainFilter<'_, K, V, F>
+#[unstable(feature = "hash_extract_if", issue = "59618")]
+impl<K, V, F> Iterator for ExtractIf<'_, K, V, F>
where
F: FnMut(&K, &mut V) -> bool,
{
@@ -2496,16 +2496,16 @@ where
}
}
-#[unstable(feature = "hash_drain_filter", issue = "59618")]
-impl<K, V, F> FusedIterator for DrainFilter<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {}
+#[unstable(feature = "hash_extract_if", issue = "59618")]
+impl<K, V, F> FusedIterator for ExtractIf<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {}
-#[unstable(feature = "hash_drain_filter", issue = "59618")]
-impl<'a, K, V, F> fmt::Debug for DrainFilter<'a, K, V, F>
+#[unstable(feature = "hash_extract_if", issue = "59618")]
+impl<'a, K, V, F> fmt::Debug for ExtractIf<'a, K, V, F>
where
F: FnMut(&K, &mut V) -> bool,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- f.debug_struct("DrainFilter").finish_non_exhaustive()
+ f.debug_struct("ExtractIf").finish_non_exhaustive()
}
}
diff --git a/library/std/src/collections/hash/map/tests.rs b/library/std/src/collections/hash/map/tests.rs
index 6b89518e2e26c..91a3776e7be84 100644
--- a/library/std/src/collections/hash/map/tests.rs
+++ b/library/std/src/collections/hash/map/tests.rs
@@ -944,7 +944,7 @@ fn test_raw_entry() {
}
}
-mod test_drain_filter {
+mod test_extract_if {
use super::*;
use crate::panic::{catch_unwind, AssertUnwindSafe};
@@ -968,7 +968,7 @@ mod test_drain_filter {
#[test]
fn empty() {
let mut map: HashMap<i32, i32> = HashMap::new();
- map.drain_filter(|_, _| unreachable!("there's nothing to decide on"));
+ map.extract_if(|_, _| unreachable!("there's nothing to decide on")).for_each(drop);
assert!(map.is_empty());
}
@@ -976,7 +976,7 @@ mod test_drain_filter {
fn consuming_nothing() {
let pairs = (0..3).map(|i| (i, i));
let mut map: HashMap<_, _> = pairs.collect();
- assert!(map.drain_filter(|_, _| false).eq_sorted(crate::iter::empty()));
+ assert!(map.extract_if(|_, _| false).eq_sorted(crate::iter::empty()));
assert_eq!(map.len(), 3);
}
@@ -984,7 +984,7 @@ mod test_drain_filter {
fn consuming_all() {
let pairs = (0..3).map(|i| (i, i));
let mut map: HashMap<_, _> = pairs.clone().collect();
- assert!(map.drain_filter(|_, _| true).eq_sorted(pairs));
+ assert!(map.extract_if(|_, _| true).eq_sorted(pairs));
assert!(map.is_empty());
}
@@ -993,7 +993,7 @@ mod test_drain_filter {
let pairs = (0..3).map(|i| (i, i));
let mut map: HashMap<_, _> = pairs.collect();
assert!(
- map.drain_filter(|_, v| {
+ map.extract_if(|_, v| {
*v += 6;
false
})
@@ -1008,7 +1008,7 @@ mod test_drain_filter {
let pairs = (0..3).map(|i| (i, i));
let mut map: HashMap<_, _> = pairs.collect();
assert!(
- map.drain_filter(|_, v| {
+ map.extract_if(|_, v| {
*v += 6;
true
})
@@ -1034,14 +1034,15 @@ mod test_drain_filter {
let mut map = (0..3).map(|i| (i, D)).collect::<HashMap<_, _>>();
catch_unwind(move || {
- drop(map.drain_filter(|_, _| {
+ map.extract_if(|_, _| {
PREDS.fetch_add(1, Ordering::SeqCst);
true
- }))
+ })
+ .for_each(drop)
})
.unwrap_err();
- assert_eq!(PREDS.load(Ordering::SeqCst), 3);
+ assert_eq!(PREDS.load(Ordering::SeqCst), 2);
assert_eq!(DROPS.load(Ordering::SeqCst), 3);
}
@@ -1060,10 +1061,11 @@ mod test_drain_filter {
let mut map = (0..3).map(|i| (i, D)).collect::<HashMap<_, _>>();
catch_unwind(AssertUnwindSafe(|| {
- drop(map.drain_filter(|_, _| match PREDS.fetch_add(1, Ordering::SeqCst) {
+ map.extract_if(|_, _| match PREDS.fetch_add(1, Ordering::SeqCst) {
0 => true,
_ => panic!(),
- }))
+ })
+ .for_each(drop)
}))
.unwrap_err();
@@ -1088,7 +1090,7 @@ mod test_drain_filter {
let mut map = (0..3).map(|i| (i, D)).collect::<HashMap<_, _>>();
{
- let mut it = map.drain_filter(|_, _| match PREDS.fetch_add(1, Ordering::SeqCst) {
+ let mut it = map.extract_if(|_, _| match PREDS.fetch_add(1, Ordering::SeqCst) {
0 => true,
_ => panic!(),
});
diff --git a/library/std/src/collections/hash/set.rs b/library/std/src/collections/hash/set.rs
index ac906e682d5f0..5bf542629f003 100644
--- a/library/std/src/collections/hash/set.rs
+++ b/library/std/src/collections/hash/set.rs
@@ -262,25 +262,24 @@ impl<T, S> HashSet<T, S> {
/// If the closure returns false, the value will remain in the list and will not be yielded
/// by the iterator.
///
- /// If the iterator is only partially consumed or not consumed at all, each of the remaining
- /// values will still be subjected to the closure and removed and dropped if it returns true.
+ /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
+ /// or the iteration short-circuits, then the remaining elements will be retained.
+ /// Use [`retain`] with a negated predicate if you do not need the returned iterator.
///
- /// It is unspecified how many more values will be subjected to the closure
- /// if a panic occurs in the closure, or if a panic occurs while dropping a value, or if the
- /// `DrainFilter` itself is leaked.
+ /// [`retain`]: HashSet::retain
///
/// # Examples
///
/// Splitting a set into even and odd values, reusing the original set:
///
/// ```
- /// #![feature(hash_drain_filter)]
+ /// #![feature(hash_extract_if)]
/// use std::collections::HashSet;
///
/// let mut set: HashSet<i32> = (0..8).collect();
- /// let drained: HashSet<i32> = set.drain_filter(|v| v % 2 == 0).collect();
+ /// let extracted: HashSet<i32> = set.extract_if(|v| v % 2 == 0).collect();
///
- /// let mut evens = drained.into_iter().collect::<Vec<_>>();
+ /// let mut evens = extracted.into_iter().collect::<Vec<_>>();
/// let mut odds = set.into_iter().collect::<Vec<_>>();
/// evens.sort();
/// odds.sort();
@@ -290,12 +289,12 @@ impl<T, S> HashSet<T, S> {
/// ```
#[inline]
#[rustc_lint_query_instability]
- #[unstable(feature = "hash_drain_filter", issue = "59618")]
- pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, T, F>
+ #[unstable(feature = "hash_extract_if", issue = "59618")]
+ pub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, T, F>
where
F: FnMut(&T) -> bool,
{
- DrainFilter { base: self.base.drain_filter(pred) }
+ ExtractIf { base: self.base.extract_if(pred) }
}
/// Retains only the elements specified by the predicate.
@@ -1310,27 +1309,27 @@ pub struct Drain<'a, K: 'a> {
/// A draining, filtering iterator over the items of a `HashSet`.
///
-/// This `struct` is created by the [`drain_filter`] method on [`HashSet`].
+/// This `struct` is created by the [`extract_if`] method on [`HashSet`].
///
-/// [`drain_filter`]: HashSet::drain_filter
+/// [`extract_if`]: HashSet::extract_if
///
/// # Examples
///
/// ```
-/// #![feature(hash_drain_filter)]
+/// #![feature(hash_extract_if)]
///
/// use std::collections::HashSet;
///
/// let mut a = HashSet::from([1, 2, 3]);
///
-/// let mut drain_filtered = a.drain_filter(|v| v % 2 == 0);
+/// let mut extract_ifed = a.extract_if(|v| v % 2 == 0);
/// ```
-#[unstable(feature = "hash_drain_filter", issue = "59618")]
-pub struct DrainFilter<'a, K, F>
+#[unstable(feature = "hash_extract_if", issue = "59618")]
+pub struct ExtractIf<'a, K, F>
where
F: FnMut(&K) -> bool,
{
- base: base::DrainFilter<'a, K, F>,
+ base: base::ExtractIf<'a, K, F>,
}
/// A lazy iterator producing elements in the intersection of `HashSet`s.
@@ -1576,8 +1575,8 @@ impl<K: fmt::Debug> fmt::Debug for Drain<'_, K> {
}
}
-#[unstable(feature = "hash_drain_filter", issue = "59618")]
-impl<K, F> Iterator for DrainFilter<'_, K, F>
+#[unstable(feature = "hash_extract_if", issue = "59618")]
+impl<K, F> Iterator for ExtractIf<'_, K, F>
where
F: FnMut(&K) -> bool,
{
@@ -1593,16 +1592,16 @@ where
}
}
-#[unstable(feature = "hash_drain_filter", issue = "59618")]
-impl<K, F> FusedIterator for DrainFilter<'_, K, F> where F: FnMut(&K) -> bool {}
+#[unstable(feature = "hash_extract_if", issue = "59618")]
+impl<K, F> FusedIterator for ExtractIf<'_, K, F> where F: FnMut(&K) -> bool {}
-#[unstable(feature = "hash_drain_filter", issue = "59618")]
-impl<'a, K, F> fmt::Debug for DrainFilter<'a, K, F>
+#[unstable(feature = "hash_extract_if", issue = "59618")]
+impl<'a, K, F> fmt::Debug for ExtractIf<'a, K, F>
where
F: FnMut(&K) -> bool,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- f.debug_struct("DrainFilter").finish_non_exhaustive()
+ f.debug_struct("ExtractIf").finish_non_exhaustive()
}
}
diff --git a/library/std/src/collections/hash/set/tests.rs b/library/std/src/collections/hash/set/tests.rs
index 941a0450cc770..7ac9eae67a090 100644
--- a/library/std/src/collections/hash/set/tests.rs
+++ b/library/std/src/collections/hash/set/tests.rs
@@ -418,18 +418,18 @@ fn test_retain() {
}
#[test]
-fn test_drain_filter() {
+fn test_extract_if() {
let mut x: HashSet<_> = [1].iter().copied().collect();
let mut y: HashSet<_> = [1].iter().copied().collect();
- x.drain_filter(|_| true);
- y.drain_filter(|_| false);
+ x.extract_if(|_| true).for_each(drop);
+ y.extract_if(|_| false).for_each(drop);
assert_eq!(x.len(), 0);
assert_eq!(y.len(), 1);
}
#[test]
-fn test_drain_filter_drop_panic_leak() {
+fn test_extract_if_drop_panic_leak() {
static PREDS: AtomicU32 = AtomicU32::new(0);
static DROPS: AtomicU32 = AtomicU32::new(0);
@@ -446,19 +446,20 @@ fn test_drain_filter_drop_panic_leak() {
let mut set = (0..3).map(|i| D(i)).collect::<HashSet<_>>();
catch_unwind(move || {
- drop(set.drain_filter(|_| {
+ set.extract_if(|_| {
PREDS.fetch_add(1, Ordering::SeqCst);
true
- }))
+ })
+ .for_each(drop)
})
.ok();
- assert_eq!(PREDS.load(Ordering::SeqCst), 3);
+ assert_eq!(PREDS.load(Ordering::SeqCst), 2);
assert_eq!(DROPS.load(Ordering::SeqCst), 3);
}
#[test]
-fn test_drain_filter_pred_panic_leak() {
+fn test_extract_if_pred_panic_leak() {
static PREDS: AtomicU32 = AtomicU32::new(0);
static DROPS: AtomicU32 = AtomicU32::new(0);
@@ -473,10 +474,11 @@ fn test_drain_filter_pred_panic_leak() {
let mut set: HashSet<_> = (0..3).map(|_| D).collect();
catch_unwind(AssertUnwindSafe(|| {
- drop(set.drain_filter(|_| match PREDS.fetch_add(1, Ordering::SeqCst) {
+ set.extract_if(|_| match PREDS.fetch_add(1, Ordering::SeqCst) {
0 => true,
_ => panic!(),
- }))
+ })
+ .for_each(drop)
}))
.ok();
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 3aa98da1c803a..870cfa93058aa 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -158,13 +158,13 @@ pub(crate) fn try_inline_glob(
.filter_map(|child| child.res.opt_def_id())
.collect();
let mut items = build_module_items(cx, did, visited, inlined_names, Some(&reexports));
- items.drain_filter(|item| {
+ items.retain(|item| {
if let Some(name) = item.name {
// If an item with the same type and name already exists,
// it takes priority over the inlined stuff.
- !inlined_names.insert((item.type_(), name))
+ inlined_names.insert((item.type_(), name))
} else {
- false
+ true
}
});
Some(items)
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 12c622e026f1e..a8cd0ec453ed7 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -6,7 +6,6 @@
#![feature(array_methods)]
#![feature(assert_matches)]
#![feature(box_patterns)]
-#![feature(drain_filter)]
#![feature(impl_trait_in_assoc_type)]
#![feature(iter_intersperse)]
#![feature(lazy_cell)]
diff --git a/src/tools/miri/tests/pass/btreemap.rs b/src/tools/miri/tests/pass/btreemap.rs
index b7c0406becc4d..1213f81a6f128 100644
--- a/src/tools/miri/tests/pass/btreemap.rs
+++ b/src/tools/miri/tests/pass/btreemap.rs
@@ -1,7 +1,7 @@
//@revisions: stack tree
//@[tree]compile-flags: -Zmiri-tree-borrows
//@compile-flags: -Zmiri-strict-provenance
-#![feature(btree_drain_filter)]
+#![feature(btree_extract_if)]
use std::collections::{BTreeMap, BTreeSet};
use std::mem;
@@ -49,8 +49,8 @@ pub fn main() {
}
test_all_refs(&mut 13, b.values_mut());
- // Test forgetting the drain.
- let mut d = b.drain_filter(|_, i| *i < 30);
+ // Test forgetting the extractor.
+ let mut d = b.extract_if(|_, i| *i < 30);
d.next().unwrap();
mem::forget(d);
}
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 9979dfbd56a12..ac2056bcc855a 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -108,6 +108,7 @@ const PERMITTED_RUSTC_DEPENDENCIES: &[&str] = &[
"adler",
"ahash",
"aho-corasick",
+ "allocator-api2", // FIXME: only appears in Cargo.lock due to https://github.com/rust-lang/cargo/issues/10801
"annotate-snippets",
"ansi_term",
"ar_archive_writer",
diff --git a/tests/ui/closures/2229_closure_analysis/run_pass/lit-pattern-matching-with-methods.rs b/tests/ui/closures/2229_closure_analysis/run_pass/lit-pattern-matching-with-methods.rs
index d2375aa69ec25..a386e9f40ccaf 100644
--- a/tests/ui/closures/2229_closure_analysis/run_pass/lit-pattern-matching-with-methods.rs
+++ b/tests/ui/closures/2229_closure_analysis/run_pass/lit-pattern-matching-with-methods.rs
@@ -2,7 +2,7 @@
//check-pass
#![warn(unused)]
#![feature(rustc_attrs)]
-#![feature(btree_drain_filter)]
+#![feature(btree_extract_if)]
use std::collections::BTreeMap;
use std::panic::{catch_unwind, AssertUnwindSafe};
@@ -14,14 +14,14 @@ fn main() {
map.insert("c", ());
{
- let mut it = map.drain_filter(|_, _| true);
+ let mut it = map.extract_if(|_, _| true);
catch_unwind(AssertUnwindSafe(|| while it.next().is_some() {})).unwrap_err();
let result = catch_unwind(AssertUnwindSafe(|| it.next()));
assert!(matches!(result, Ok(None)));
}
{
- let mut it = map.drain_filter(|_, _| true);
+ let mut it = map.extract_if(|_, _| true);
catch_unwind(AssertUnwindSafe(|| while let Some(_) = it.next() {})).unwrap_err();
let result = catch_unwind(AssertUnwindSafe(|| it.next()));
assert!(matches!(result, Ok(None)));