Auto merge of #104455 - the8472:dont-drain-on-drop, r=Amanieu

Don't drain-on-drop in DrainFilter impls of various collections.

This removes drain-on-drop behavior from various unstable DrainFilter impls (not yet for HashSet/Map) because that behavior [is problematic](#43244 (comment)) (because it can lead to panic-in-drop when user closures panic) and may become forbidden if [this draft RFC passes](rust-lang/rfcs#3288).

closes #101122

[ACP](rust-lang/libs-team#136)

affected tracking issues
* #43244
* #70530
* #59618

Related hashbrown update: rust-lang/hashbrown#374

Author: bors

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",

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() {

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)]

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.

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"]

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)]

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

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)]

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;
 

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)]

compiler/rustc_mir_transform/src/sroa.rs

@@ -436,26 +436,24 @@ 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)
                         {
                             new_fragments.extend(frg.into_iter().map(|mut f| {
                                 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);

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);
     }

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::")
             })

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)]

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)]

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(..))

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 {

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]

library/alloc/benches/btree/map.rs

@@ -385,15 +385,15 @@ 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]
 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);
     })
 }
@@ -456,15 +456,15 @@ 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]
 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);
     })
 }
@@ -527,15 +527,15 @@ 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]
 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);
     })
 }

library/alloc/benches/btree/set.rs

@@ -69,15 +69,15 @@ 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]
 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);
     })
 }
@@ -140,15 +140,15 @@ 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]
 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);
     })
 }

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)]