Use (😏) precise capture instead of Captures trait hack

precise capture

Author: yotamofek

compiler/rustc_ast_lowering/src/lib.rs

@@ -43,7 +43,6 @@
 
 use rustc_ast::node_id::NodeMap;
 use rustc_ast::{self as ast, *};
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -1803,7 +1802,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         &'s mut self,
         params: &'s [GenericParam],
         source: hir::GenericParamSource,
-    ) -> impl Iterator<Item = hir::GenericParam<'hir>> + Captures<'a> + Captures<'s> {
+    ) -> impl Iterator<Item = hir::GenericParam<'hir>> + use<'a, 'hir, 's> {
         params.iter().map(move |param| self.lower_generic_param(param, source))
     }
 
@@ -1968,7 +1967,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         &'s mut self,
         bounds: &'s [GenericBound],
         itctx: ImplTraitContext,
-    ) -> impl Iterator<Item = hir::GenericBound<'hir>> + Captures<'s> + Captures<'a> {
+    ) -> impl Iterator<Item = hir::GenericBound<'hir>> + use<'a, 'hir, 's> {
         bounds.iter().map(move |bound| self.lower_param_bound(bound, itctx))
     }
 

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -8,7 +8,6 @@ use std::ops::ControlFlow;
 
 use either::Either;
 use hir::{ClosureKind, Path};
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, Diag, MultiSpan, struct_span_code_err};
@@ -3524,7 +3523,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         fn predecessor_locations<'a, 'tcx>(
             body: &'a mir::Body<'tcx>,
             location: Location,
-        ) -> impl Iterator<Item = Location> + Captures<'tcx> + 'a {
+        ) -> impl Iterator<Item = Location> + use<'a, 'tcx> {
             if location.statement_index == 0 {
                 let predecessors = body.basic_blocks.predecessors()[location.block].to_vec();
                 Either::Left(predecessors.into_iter().map(move |bb| body.terminator_loc(bb)))

compiler/rustc_borrowck/src/member_constraints.rs

@@ -1,7 +1,6 @@
 use std::hash::Hash;
 use std::ops::Index;
 
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::ty::{self, Ty};
@@ -149,7 +148,7 @@ where
 {
     pub(crate) fn all_indices(
         &self,
-    ) -> impl Iterator<Item = NllMemberConstraintIndex> + Captures<'tcx> + '_ {
+    ) -> impl Iterator<Item = NllMemberConstraintIndex> + use<'tcx, '_, R> {
         self.constraints.indices()
     }
 
@@ -159,7 +158,7 @@ where
     pub(crate) fn indices(
         &self,
         member_region_vid: R,
-    ) -> impl Iterator<Item = NllMemberConstraintIndex> + Captures<'tcx> + '_ {
+    ) -> impl Iterator<Item = NllMemberConstraintIndex> + use<'tcx, '_, R> {
         let mut next = self.first_constraints.get(&member_region_vid).cloned();
         std::iter::from_fn(move || -> Option<NllMemberConstraintIndex> {
             if let Some(current) = next {

compiler/rustc_data_structures/src/captures.rs

@@ -48,7 +48,6 @@ pub use rustc_index::static_assert_size;
 pub mod aligned;
 pub mod base_n;
 pub mod binary_search_util;
-pub mod captures;
 pub mod fingerprint;
 pub mod flat_map_in_place;
 pub mod flock;

compiler/rustc_data_structures/src/lib.rs

@@ -20,7 +20,6 @@ use std::ops::Bound;
 
 use rustc_abi::ExternAbi;
 use rustc_ast::Recovered;
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_data_structures::unord::UnordMap;
 use rustc_errors::{
@@ -1705,7 +1704,7 @@ fn polarity_of_impl(
 fn early_bound_lifetimes_from_generics<'a, 'tcx: 'a>(
     tcx: TyCtxt<'tcx>,
     generics: &'a hir::Generics<'a>,
-) -> impl Iterator<Item = &'a hir::GenericParam<'a>> + Captures<'tcx> {
+) -> impl Iterator<Item = &'a hir::GenericParam<'a>> + use<'a, 'tcx> {
     generics.params.iter().filter(move |param| match param.kind {
         GenericParamKind::Lifetime { .. } => !tcx.is_late_bound(param.hir_id),
         _ => false,

compiler/rustc_hir_analysis/src/collect.rs

@@ -10,7 +10,6 @@
 use std::fmt::Debug;
 use std::iter;
 
-use rustc_data_structures::captures::Captures;
 use rustc_index::{Idx, IndexVec};
 use rustc_middle::arena::ArenaAllocatable;
 use rustc_middle::mir::ConstraintCategory;
@@ -547,7 +546,7 @@ impl<'tcx> InferCtxt<'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         uninstantiated_region_constraints: &'a [QueryOutlivesConstraint<'tcx>],
         result_args: &'a CanonicalVarValues<'tcx>,
-    ) -> impl Iterator<Item = PredicateObligation<'tcx>> + 'a + Captures<'tcx> {
+    ) -> impl Iterator<Item = PredicateObligation<'tcx>> + 'a {
         uninstantiated_region_constraints.iter().map(move |&constraint| {
             let predicate = instantiate_value(self.tcx, result_args, constraint);
             self.query_outlives_constraint_to_obligation(predicate, cause.clone(), param_env)

compiler/rustc_infer/src/infer/canonical/query_response.rs

@@ -15,7 +15,6 @@ use region_constraints::{
 };
 pub use relate::StructurallyRelateAliases;
 pub use relate::combine::PredicateEmittingRelation;
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_data_structures::undo_log::{Rollback, UndoLogs};
 use rustc_data_structures::unify as ut;
@@ -1297,7 +1296,7 @@ impl<'tcx> InferCtxt<'tcx> {
     #[inline]
     pub fn is_ty_infer_var_definitely_unchanged<'a>(
         &'a self,
-    ) -> (impl Fn(TyOrConstInferVar) -> bool + Captures<'tcx> + 'a) {
+    ) -> (impl Fn(TyOrConstInferVar) -> bool + use<'tcx, 'a>) {
         // This hoists the borrow/release out of the loop body.
         let inner = self.inner.try_borrow();
 

compiler/rustc_infer/src/infer/mod.rs

@@ -7,7 +7,6 @@ use std::{io, iter, mem};
 pub(super) use cstore_impl::provide;
 use proc_macro::bridge::client::ProcMacro;
 use rustc_ast as ast;
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::owned_slice::OwnedSlice;
@@ -958,7 +957,7 @@ impl CrateRoot {
     pub(crate) fn decode_crate_deps<'a>(
         &self,
         metadata: &'a MetadataBlob,
-    ) -> impl ExactSizeIterator<Item = CrateDep> + Captures<'a> {
+    ) -> impl ExactSizeIterator<Item = CrateDep> + 'a {
         self.crate_deps.decode(metadata)
     }
 }

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -12,7 +12,6 @@ use either::Either;
 use polonius_engine::Atom;
 use rustc_abi::{FieldIdx, VariantIdx};
 pub use rustc_ast::Mutability;
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_errors::{DiagArgName, DiagArgValue, DiagMessage, ErrorGuaranteed, IntoDiagArg};
@@ -481,7 +480,7 @@ impl<'tcx> Body<'tcx> {
 
     /// Returns an iterator over all user-declared mutable locals.
     #[inline]
-    pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + Captures<'tcx> + 'a {
+    pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + use<'tcx, 'a> {
         (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
             let local = Local::new(index);
             let decl = &self.local_decls[local];
@@ -491,9 +490,7 @@ impl<'tcx> Body<'tcx> {
 
     /// Returns an iterator over all user-declared mutable arguments and locals.
     #[inline]
-    pub fn mut_vars_and_args_iter<'a>(
-        &'a self,
-    ) -> impl Iterator<Item = Local> + Captures<'tcx> + 'a {
+    pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + use<'tcx, 'a> {
         (1..self.local_decls.len()).filter_map(move |index| {
             let local = Local::new(index);
             let decl = &self.local_decls[local];

compiler/rustc_middle/src/mir/mod.rs

@@ -4,7 +4,6 @@ use std::ops::Range;
 use std::str;
 
 use rustc_abi::{FIRST_VARIANT, ReprOptions, VariantIdx};
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::intern::Interned;
@@ -536,7 +535,7 @@ impl<'tcx> AdtDef<'tcx> {
     pub fn discriminants(
         self,
         tcx: TyCtxt<'tcx>,
-    ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
+    ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + 'tcx {
         assert!(self.is_enum());
         let repr_type = self.repr().discr_type();
         let initial = repr_type.initial_discriminant(tcx);

compiler/rustc_middle/src/ty/adt.rs

@@ -1,6 +1,5 @@
 use std::fmt::Write;
 
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_hir as hir;
 use rustc_hir::HirId;
@@ -415,7 +414,7 @@ pub fn analyze_coroutine_closure_captures<'a, 'tcx: 'a, T>(
     parent_captures: impl IntoIterator<Item = &'a CapturedPlace<'tcx>>,
     child_captures: impl IntoIterator<Item = &'a CapturedPlace<'tcx>>,
     mut for_each: impl FnMut((usize, &'a CapturedPlace<'tcx>), (usize, &'a CapturedPlace<'tcx>)) -> T,
-) -> impl Iterator<Item = T> + Captures<'a> + Captures<'tcx> {
+) -> impl Iterator<Item = T> {
     std::iter::from_coroutine(
         #[coroutine]
         move || {

compiler/rustc_middle/src/ty/closure.rs

@@ -1,6 +1,5 @@
 use std::cmp::Ordering;
 
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::intern::Interned;
 use rustc_hir::def_id::DefId;
 use rustc_macros::{HashStable, extension};
@@ -350,7 +349,7 @@ impl<'tcx> ty::List<ty::PolyExistentialPredicate<'tcx>> {
     }
 
     #[inline]
-    pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'a {
+    pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item = DefId> + use<'tcx, 'a> {
         self.iter().filter_map(|predicate| match predicate.skip_binder() {
             ExistentialPredicate::AutoTrait(did) => Some(did),
             _ => None,

compiler/rustc_middle/src/ty/predicate.rs

@@ -9,7 +9,6 @@ use std::ops::{ControlFlow, Range};
 
 use hir::def::{CtorKind, DefKind};
 use rustc_abi::{ExternAbi, FIRST_VARIANT, FieldIdx, VariantIdx};
-use rustc_data_structures::captures::Captures;
 use rustc_errors::{ErrorGuaranteed, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::LangItem;
@@ -105,7 +104,7 @@ impl<'tcx> ty::CoroutineArgs<TyCtxt<'tcx>> {
         self,
         def_id: DefId,
         tcx: TyCtxt<'tcx>,
-    ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
+    ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> {
         self.variant_range(def_id, tcx).map(move |index| {
             (index, Discr { val: index.as_usize() as u128, ty: self.discr_ty(tcx) })
         })
@@ -139,7 +138,7 @@ impl<'tcx> ty::CoroutineArgs<TyCtxt<'tcx>> {
         self,
         def_id: DefId,
         tcx: TyCtxt<'tcx>,
-    ) -> impl Iterator<Item: Iterator<Item = Ty<'tcx>> + Captures<'tcx>> {
+    ) -> impl Iterator<Item: Iterator<Item = Ty<'tcx>>> {
         let layout = tcx.coroutine_layout(def_id, self.kind_ty()).unwrap();
         layout.variant_fields.iter().map(move |variant| {
             variant.iter().map(move |field| {

compiler/rustc_middle/src/ty/sty.rs

@@ -2,7 +2,6 @@ use std::fmt::{Debug, Formatter};
 use std::ops::Range;
 
 use rustc_abi::{FieldIdx, VariantIdx};
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashMap, FxIndexSet, StdEntry};
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_index::IndexVec;
@@ -677,10 +676,7 @@ impl<'tcx> Map<'tcx> {
     }
 
     /// Iterate over all direct children.
-    fn children(
-        &self,
-        parent: PlaceIndex,
-    ) -> impl Iterator<Item = PlaceIndex> + Captures<'_> + Captures<'tcx> {
+    fn children(&self, parent: PlaceIndex) -> impl Iterator<Item = PlaceIndex> + use<'tcx, '_> {
         Children::new(self, parent)
     }
 

compiler/rustc_mir_dataflow/src/value_analysis.rs

@@ -1,7 +1,6 @@
 use std::cmp::Ordering;
 use std::fmt::{self, Debug};
 
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::graph::DirectedGraph;
 use rustc_index::IndexVec;
@@ -144,17 +143,15 @@ impl CoverageCounters {
     /// Returns an iterator over all the nodes/edges in the coverage graph that
     /// should have a counter-increment statement injected into MIR, along with
     /// each site's corresponding counter ID.
-    pub(super) fn counter_increment_sites(
-        &self,
-    ) -> impl Iterator<Item = (CounterId, Site)> + Captures<'_> {
+    pub(super) fn counter_increment_sites(&self) -> impl Iterator<Item = (CounterId, Site)> + '_ {
         self.counter_increment_sites.iter_enumerated().map(|(id, &site)| (id, site))
     }
 
     /// Returns an iterator over the subset of BCB nodes that have been associated
     /// with a counter *expression*, along with the ID of that expression.
     pub(super) fn bcb_nodes_with_coverage_expressions(
         &self,
-    ) -> impl Iterator<Item = (BasicCoverageBlock, ExpressionId)> + Captures<'_> {
+    ) -> impl Iterator<Item = (BasicCoverageBlock, ExpressionId)> + '_ {
         self.node_counters.iter_enumerated().filter_map(|(bcb, &counter)| match counter {
             // Yield the BCB along with its associated expression ID.
             Some(BcbCounter::Expression { id }) => Some((bcb, id)),
@@ -212,7 +209,7 @@ fn sibling_out_edge_targets(
     graph: &CoverageGraph,
     from_bcb: BasicCoverageBlock,
     to_bcb: BasicCoverageBlock,
-) -> impl Iterator<Item = BasicCoverageBlock> + Captures<'_> {
+) -> impl Iterator<Item = BasicCoverageBlock> + '_ {
     graph.successors[from_bcb].iter().copied().filter(move |&t| t != to_bcb)
 }
 

compiler/rustc_mir_transform/src/coverage/counters.rs

@@ -3,7 +3,6 @@ use std::collections::VecDeque;
 use std::ops::{Index, IndexMut};
 use std::{iter, mem, slice};
 
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_data_structures::graph::{self, DirectedGraph, StartNode};
@@ -246,7 +245,7 @@ impl CoverageGraph {
     pub(crate) fn loop_headers_containing(
         &self,
         bcb: BasicCoverageBlock,
-    ) -> impl Iterator<Item = BasicCoverageBlock> + Captures<'_> {
+    ) -> impl Iterator<Item = BasicCoverageBlock> + '_ {
         let self_if_loop_header = self.is_loop_header.contains(bcb).then_some(bcb).into_iter();
 
         let mut curr = Some(bcb);
@@ -266,7 +265,7 @@ impl CoverageGraph {
     pub(crate) fn reloop_predecessors(
         &self,
         to_bcb: BasicCoverageBlock,
-    ) -> impl Iterator<Item = BasicCoverageBlock> + Captures<'_> {
+    ) -> impl Iterator<Item = BasicCoverageBlock> + '_ {
         self.predecessors[to_bcb].iter().copied().filter(move |&pred| self.dominates(to_bcb, pred))
     }
 }

compiler/rustc_mir_transform/src/coverage/graph.rs

@@ -1,4 +1,3 @@
-use rustc_data_structures::captures::Captures;
 use rustc_index::bit_set::DenseBitSet;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::coverage::{
@@ -134,7 +133,7 @@ fn coverage_ids_info<'tcx>(
 
 fn all_coverage_in_mir_body<'a, 'tcx>(
     body: &'a Body<'tcx>,
-) -> impl Iterator<Item = &'a CoverageKind> + Captures<'tcx> {
+) -> impl Iterator<Item = &'a CoverageKind> + use<'a, 'tcx> {
     body.basic_blocks.iter().flat_map(|bb_data| &bb_data.statements).filter_map(|statement| {
         match statement.kind {
             StatementKind::Coverage(ref kind) if !is_inlined(body, statement) => Some(kind),

compiler/rustc_mir_transform/src/coverage/query.rs

@@ -1,6 +1,5 @@
 use std::collections::VecDeque;
 
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::mir;
 use rustc_span::{DesugaringKind, ExpnKind, MacroKind, Span};
@@ -179,10 +178,10 @@ fn divide_spans_into_buckets(input_covspans: Vec<Covspan>, holes: &[Hole]) -> Ve
 
 /// Similar to `.drain(..)`, but stops just before it would remove an item not
 /// satisfying the predicate.
-fn drain_front_while<'a, T>(
+fn drain_front_while<'a, T, F: FnMut(&T) -> bool>(
     queue: &'a mut VecDeque<T>,
-    mut pred_fn: impl FnMut(&T) -> bool,
-) -> impl Iterator<Item = T> + Captures<'a> {
+    mut pred_fn: F,
+) -> impl Iterator<Item = T> + use<'a, T, F> {
     std::iter::from_fn(move || if pred_fn(queue.front()?) { queue.pop_front() } else { None })
 }
 

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -6,6 +6,7 @@
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
 #![cfg_attr(feature = "rustc", feature(let_chains))]
+#![cfg_attr(feature = "rustc", feature(precise_capturing_in_traits))]
 #![warn(unreachable_pub)]
 // tidy-alphabetical-end
 

compiler/rustc_pattern_analysis/src/lib.rs

@@ -1,6 +1,6 @@
 use crate::constructor::{Constructor, SplitConstructorSet};
 use crate::pat::{DeconstructedPat, PatOrWild};
-use crate::{Captures, MatchArm, PatCx};
+use crate::{MatchArm, PatCx};
 
 /// A column of patterns in a match, where a column is the intuitive notion of "subpatterns that
 /// inspect the same subvalue/place".
@@ -41,7 +41,7 @@ impl<'p, Cx: PatCx> PatternColumn<'p, Cx> {
     pub fn head_ty(&self) -> Option<&Cx::Ty> {
         self.patterns.first().map(|pat| pat.ty())
     }
-    pub fn iter<'a>(&'a self) -> impl Iterator<Item = &'p DeconstructedPat<Cx>> + Captures<'a> {
+    pub fn iter<'a>(&'a self) -> impl Iterator<Item = &'p DeconstructedPat<Cx>> + use<'p, 'a, Cx> {
         self.patterns.iter().copied()
     }