diff --git a/compiler/rustc_infer/src/traits/util.rs b/compiler/rustc_infer/src/traits/util.rs
index ab8ada1596c81..66ed49fe32676 100644
--- a/compiler/rustc_infer/src/traits/util.rs
+++ b/compiler/rustc_infer/src/traits/util.rs
@@ -1,5 +1,5 @@
 use rustc_data_structures::fx::FxHashSet;
-use rustc_middle::ty::{self, ToPolyTraitRef, TyCtxt};
+use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::{Ident, Span};
 pub use rustc_type_ir::elaborate::*;
 
@@ -125,8 +125,8 @@ pub fn transitive_bounds_that_define_assoc_item<'tcx>(
                     .iter_identity_copied()
                     .map(|(clause, _)| clause.instantiate_supertrait(tcx, trait_ref))
                     .filter_map(|clause| clause.as_trait_clause())
-                    // FIXME: Negative supertraits are elaborated here lol
-                    .map(|trait_pred| trait_pred.to_poly_trait_ref()),
+                    .filter(|clause| clause.polarity() == ty::PredicatePolarity::Positive)
+                    .map(|clause| clause.map_bound(|clause| clause.trait_ref)),
             );
 
             return Some(trait_ref);
diff --git a/compiler/rustc_middle/src/mir/coverage.rs b/compiler/rustc_middle/src/mir/coverage.rs
index cd6b2d65bf184..65f51ae9d39c6 100644
--- a/compiler/rustc_middle/src/mir/coverage.rs
+++ b/compiler/rustc_middle/src/mir/coverage.rs
@@ -71,11 +71,7 @@ impl ConditionId {
 
 /// Enum that can hold a constant zero value, the ID of an physical coverage
 /// counter, or the ID of a coverage-counter expression.
-///
-/// This was originally only used for expression operands (and named `Operand`),
-/// but the zero/counter/expression distinction is also useful for representing
-/// the value of code/gap mappings, and the true/false arms of branch mappings.
-#[derive(Copy, Clone, PartialEq, Eq)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
 #[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub enum CovTerm {
     Zero,
@@ -171,7 +167,7 @@ impl Op {
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 #[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub struct Expression {
     pub lhs: CovTerm,
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index d2875fb37944a..ca70ae794c530 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -79,8 +79,7 @@ pub use self::predicate::{
     PolyExistentialPredicate, PolyExistentialProjection, PolyExistentialTraitRef,
     PolyProjectionPredicate, PolyRegionOutlivesPredicate, PolySubtypePredicate, PolyTraitPredicate,
     PolyTraitRef, PolyTypeOutlivesPredicate, Predicate, PredicateKind, ProjectionPredicate,
-    RegionOutlivesPredicate, SubtypePredicate, ToPolyTraitRef, TraitPredicate, TraitRef,
-    TypeOutlivesPredicate,
+    RegionOutlivesPredicate, SubtypePredicate, TraitPredicate, TraitRef, TypeOutlivesPredicate,
 };
 pub use self::region::{
     BoundRegion, BoundRegionKind, EarlyParamRegion, LateParamRegion, LateParamRegionKind, Region,
diff --git a/compiler/rustc_middle/src/ty/predicate.rs b/compiler/rustc_middle/src/ty/predicate.rs
index 32d6455e82557..584cac22ae8dd 100644
--- a/compiler/rustc_middle/src/ty/predicate.rs
+++ b/compiler/rustc_middle/src/ty/predicate.rs
@@ -476,16 +476,6 @@ impl<'tcx> Clause<'tcx> {
     }
 }
 
-pub trait ToPolyTraitRef<'tcx> {
-    fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
-}
-
-impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
-    fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
-        self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
-    }
-}
-
 impl<'tcx> UpcastFrom<TyCtxt<'tcx>, PredicateKind<'tcx>> for Predicate<'tcx> {
     fn upcast_from(from: PredicateKind<'tcx>, tcx: TyCtxt<'tcx>) -> Self {
         ty::Binder::dummy(from).upcast(tcx)
diff --git a/compiler/rustc_mir_transform/src/coverage/counters.rs b/compiler/rustc_mir_transform/src/coverage/counters.rs
index 1a9323329f61f..8d397f63cc7e0 100644
--- a/compiler/rustc_mir_transform/src/coverage/counters.rs
+++ b/compiler/rustc_mir_transform/src/coverage/counters.rs
@@ -1,10 +1,9 @@
 use std::cmp::Ordering;
-use std::fmt::{self, Debug};
 
 use either::Either;
 use itertools::Itertools;
 use rustc_data_structures::captures::Captures;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::graph::DirectedGraph;
 use rustc_index::IndexVec;
 use rustc_index::bit_set::DenseBitSet;
@@ -20,134 +19,163 @@ mod iter_nodes;
 mod node_flow;
 mod union_find;
 
-/// The coverage counter or counter expression associated with a particular
-/// BCB node or BCB edge.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-enum BcbCounter {
-    Counter { id: CounterId },
-    Expression { id: ExpressionId },
+/// Ensures that each BCB node needing a counter has one, by creating physical
+/// counters or counter expressions for nodes as required.
+pub(super) fn make_bcb_counters(
+    graph: &CoverageGraph,
+    bcb_needs_counter: &DenseBitSet<BasicCoverageBlock>,
+) -> CoverageCounters {
+    // Create the derived graphs that are necessary for subsequent steps.
+    let balanced_graph = BalancedFlowGraph::for_graph(graph, |n| !graph[n].is_out_summable);
+    let merged_graph = MergedNodeFlowGraph::for_balanced_graph(&balanced_graph);
+
+    // Use those graphs to determine which nodes get physical counters, and how
+    // to compute the execution counts of other nodes from those counters.
+    let nodes = make_node_counter_priority_list(graph, balanced_graph);
+    let node_counters = merged_graph.make_node_counters(&nodes);
+
+    // Convert the counters into a form suitable for embedding into MIR.
+    transcribe_counters(&node_counters, bcb_needs_counter)
 }
 
-impl BcbCounter {
-    fn as_term(&self) -> CovTerm {
-        match *self {
-            BcbCounter::Counter { id, .. } => CovTerm::Counter(id),
-            BcbCounter::Expression { id, .. } => CovTerm::Expression(id),
-        }
-    }
+/// Arranges the nodes in `balanced_graph` into a list, such that earlier nodes
+/// take priority in being given a counter expression instead of a physical counter.
+fn make_node_counter_priority_list(
+    graph: &CoverageGraph,
+    balanced_graph: BalancedFlowGraph<&CoverageGraph>,
+) -> Vec<BasicCoverageBlock> {
+    // A "reloop" node has exactly one out-edge, which jumps back to the top
+    // of an enclosing loop. Reloop nodes are typically visited more times
+    // than loop-exit nodes, so try to avoid giving them physical counters.
+    let is_reloop_node = IndexVec::from_fn_n(
+        |node| match graph.successors[node].as_slice() {
+            &[succ] => graph.dominates(succ, node),
+            _ => false,
+        },
+        graph.num_nodes(),
+    );
+
+    let mut nodes = balanced_graph.iter_nodes().rev().collect::<Vec<_>>();
+    // The first node is the sink, which must not get a physical counter.
+    assert_eq!(nodes[0], balanced_graph.sink);
+    // Sort the real nodes, such that earlier (lesser) nodes take priority
+    // in being given a counter expression instead of a physical counter.
+    nodes[1..].sort_by(|&a, &b| {
+        // Start with a dummy `Equal` to make the actual tests line up nicely.
+        Ordering::Equal
+            // Prefer a physical counter for return/yield nodes.
+            .then_with(|| Ord::cmp(&graph[a].is_out_summable, &graph[b].is_out_summable))
+            // Prefer an expression for reloop nodes (see definition above).
+            .then_with(|| Ord::cmp(&is_reloop_node[a], &is_reloop_node[b]).reverse())
+            // Otherwise, prefer a physical counter for dominating nodes.
+            .then_with(|| graph.cmp_in_dominator_order(a, b).reverse())
+    });
+    nodes
 }
 
-impl Debug for BcbCounter {
-    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::Counter { id, .. } => write!(fmt, "Counter({:?})", id.index()),
-            Self::Expression { id } => write!(fmt, "Expression({:?})", id.index()),
+// Converts node counters into a form suitable for embedding into MIR.
+fn transcribe_counters(
+    old: &NodeCounters<BasicCoverageBlock>,
+    bcb_needs_counter: &DenseBitSet<BasicCoverageBlock>,
+) -> CoverageCounters {
+    let mut new = CoverageCounters::with_num_bcbs(bcb_needs_counter.domain_size());
+
+    for bcb in bcb_needs_counter.iter() {
+        // Our counter-creation algorithm doesn't guarantee that a counter
+        // expression starts or ends with a positive term, so partition the
+        // counters into "positive" and "negative" lists for easier handling.
+        let (mut pos, mut neg): (Vec<_>, Vec<_>) =
+            old.counter_expr(bcb).iter().partition_map(|&CounterTerm { node, op }| match op {
+                Op::Add => Either::Left(node),
+                Op::Subtract => Either::Right(node),
+            });
+
+        if pos.is_empty() {
+            // If we somehow end up with no positive terms, fall back to
+            // creating a physical counter. There's no known way for this
+            // to happen, but we can avoid an ICE if it does.
+            debug_assert!(false, "{bcb:?} has no positive counter terms");
+            pos = vec![bcb];
+            neg = vec![];
         }
-    }
-}
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-struct BcbExpression {
-    lhs: BcbCounter,
-    op: Op,
-    rhs: BcbCounter,
-}
+        // These intermediate sorts are not strictly necessary, but were helpful
+        // in reducing churn when switching to the current counter-creation scheme.
+        // They also help to slightly decrease the overall size of the expression
+        // table, due to more subexpressions being shared.
+        pos.sort();
+        neg.sort();
+
+        let mut new_counters_for_sites = |sites: Vec<BasicCoverageBlock>| {
+            sites.into_iter().map(|node| new.ensure_phys_counter(node)).collect::<Vec<_>>()
+        };
+        let mut pos = new_counters_for_sites(pos);
+        let mut neg = new_counters_for_sites(neg);
+
+        // These sorts are also not strictly necessary; see above.
+        pos.sort();
+        neg.sort();
+
+        let pos_counter = new.make_sum(&pos).expect("`pos` should not be empty");
+        let new_counter = new.make_subtracted_sum(pos_counter, &neg);
+        new.set_node_counter(bcb, new_counter);
+    }
 
-/// Enum representing either a node or an edge in the coverage graph.
-///
-/// FIXME(#135481): This enum is no longer needed now that we only instrument
-/// nodes and not edges. It can be removed in a subsequent PR.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub(super) enum Site {
-    Node { bcb: BasicCoverageBlock },
+    new
 }
 
 /// Generates and stores coverage counter and coverage expression information
-/// associated with nodes/edges in the BCB graph.
+/// associated with nodes in the coverage graph.
 pub(super) struct CoverageCounters {
     /// List of places where a counter-increment statement should be injected
     /// into MIR, each with its corresponding counter ID.
-    counter_increment_sites: IndexVec<CounterId, Site>,
+    phys_counter_for_node: FxIndexMap<BasicCoverageBlock, CounterId>,
+    next_counter_id: CounterId,
 
     /// Coverage counters/expressions that are associated with individual BCBs.
-    node_counters: IndexVec<BasicCoverageBlock, Option<BcbCounter>>,
+    node_counters: IndexVec<BasicCoverageBlock, Option<CovTerm>>,
 
     /// Table of expression data, associating each expression ID with its
     /// corresponding operator (+ or -) and its LHS/RHS operands.
-    expressions: IndexVec<ExpressionId, BcbExpression>,
+    expressions: IndexVec<ExpressionId, Expression>,
     /// Remember expressions that have already been created (or simplified),
     /// so that we don't create unnecessary duplicates.
-    expressions_memo: FxHashMap<BcbExpression, BcbCounter>,
+    expressions_memo: FxHashMap<Expression, CovTerm>,
 }
 
 impl CoverageCounters {
-    /// Ensures that each BCB node needing a counter has one, by creating physical
-    /// counters or counter expressions for nodes and edges as required.
-    pub(super) fn make_bcb_counters(
-        graph: &CoverageGraph,
-        bcb_needs_counter: &DenseBitSet<BasicCoverageBlock>,
-    ) -> Self {
-        let balanced_graph = BalancedFlowGraph::for_graph(graph, |n| !graph[n].is_out_summable);
-        let merged_graph = MergedNodeFlowGraph::for_balanced_graph(&balanced_graph);
-
-        // A "reloop" node has exactly one out-edge, which jumps back to the top
-        // of an enclosing loop. Reloop nodes are typically visited more times
-        // than loop-exit nodes, so try to avoid giving them physical counters.
-        let is_reloop_node = IndexVec::from_fn_n(
-            |node| match graph.successors[node].as_slice() {
-                &[succ] => graph.dominates(succ, node),
-                _ => false,
-            },
-            graph.num_nodes(),
-        );
-
-        let mut nodes = balanced_graph.iter_nodes().rev().collect::<Vec<_>>();
-        // The first node is the sink, which must not get a physical counter.
-        assert_eq!(nodes[0], balanced_graph.sink);
-        // Sort the real nodes, such that earlier (lesser) nodes take priority
-        // in being given a counter expression instead of a physical counter.
-        nodes[1..].sort_by(|&a, &b| {
-            // Start with a dummy `Equal` to make the actual tests line up nicely.
-            Ordering::Equal
-                // Prefer a physical counter for return/yield nodes.
-                .then_with(|| Ord::cmp(&graph[a].is_out_summable, &graph[b].is_out_summable))
-                // Prefer an expression for reloop nodes (see definition above).
-                .then_with(|| Ord::cmp(&is_reloop_node[a], &is_reloop_node[b]).reverse())
-                // Otherwise, prefer a physical counter for dominating nodes.
-                .then_with(|| graph.cmp_in_dominator_order(a, b).reverse())
-        });
-        let node_counters = merged_graph.make_node_counters(&nodes);
-
-        Transcriber::new(graph.num_nodes(), node_counters).transcribe_counters(bcb_needs_counter)
-    }
-
     fn with_num_bcbs(num_bcbs: usize) -> Self {
         Self {
-            counter_increment_sites: IndexVec::new(),
+            phys_counter_for_node: FxIndexMap::default(),
+            next_counter_id: CounterId::ZERO,
             node_counters: IndexVec::from_elem_n(None, num_bcbs),
             expressions: IndexVec::new(),
             expressions_memo: FxHashMap::default(),
         }
     }
 
-    /// Creates a new physical counter for a BCB node or edge.
-    fn make_phys_counter(&mut self, site: Site) -> BcbCounter {
-        let id = self.counter_increment_sites.push(site);
-        BcbCounter::Counter { id }
+    /// Returns the physical counter for the given node, creating it if necessary.
+    fn ensure_phys_counter(&mut self, bcb: BasicCoverageBlock) -> CovTerm {
+        let id = *self.phys_counter_for_node.entry(bcb).or_insert_with(|| {
+            let id = self.next_counter_id;
+            self.next_counter_id = id + 1;
+            id
+        });
+        CovTerm::Counter(id)
     }
 
-    fn make_expression(&mut self, lhs: BcbCounter, op: Op, rhs: BcbCounter) -> BcbCounter {
-        let new_expr = BcbExpression { lhs, op, rhs };
-        *self.expressions_memo.entry(new_expr).or_insert_with(|| {
+    fn make_expression(&mut self, lhs: CovTerm, op: Op, rhs: CovTerm) -> CovTerm {
+        let new_expr = Expression { lhs, op, rhs };
+        *self.expressions_memo.entry(new_expr.clone()).or_insert_with(|| {
             let id = self.expressions.push(new_expr);
-            BcbCounter::Expression { id }
+            CovTerm::Expression(id)
         })
     }
 
     /// Creates a counter that is the sum of the given counters.
     ///
     /// Returns `None` if the given list of counters was empty.
-    fn make_sum(&mut self, counters: &[BcbCounter]) -> Option<BcbCounter> {
+    fn make_sum(&mut self, counters: &[CovTerm]) -> Option<CovTerm> {
         counters
             .iter()
             .copied()
@@ -155,16 +183,18 @@ impl CoverageCounters {
     }
 
     /// Creates a counter whose value is `lhs - SUM(rhs)`.
-    fn make_subtracted_sum(&mut self, lhs: BcbCounter, rhs: &[BcbCounter]) -> BcbCounter {
+    fn make_subtracted_sum(&mut self, lhs: CovTerm, rhs: &[CovTerm]) -> CovTerm {
         let Some(rhs_sum) = self.make_sum(rhs) else { return lhs };
         self.make_expression(lhs, Op::Subtract, rhs_sum)
     }
 
     pub(super) fn num_counters(&self) -> usize {
-        self.counter_increment_sites.len()
+        let num_counters = self.phys_counter_for_node.len();
+        assert_eq!(num_counters, self.next_counter_id.as_usize());
+        num_counters
     }
 
-    fn set_node_counter(&mut self, bcb: BasicCoverageBlock, counter: BcbCounter) -> BcbCounter {
+    fn set_node_counter(&mut self, bcb: BasicCoverageBlock, counter: CovTerm) -> CovTerm {
         let existing = self.node_counters[bcb].replace(counter);
         assert!(
             existing.is_none(),
@@ -174,16 +204,16 @@ impl CoverageCounters {
     }
 
     pub(super) fn term_for_bcb(&self, bcb: BasicCoverageBlock) -> Option<CovTerm> {
-        self.node_counters[bcb].map(|counter| counter.as_term())
+        self.node_counters[bcb]
     }
 
-    /// Returns an iterator over all the nodes/edges in the coverage graph that
+    /// Returns an iterator over all the nodes 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<'_> {
-        self.counter_increment_sites.iter_enumerated().map(|(id, &site)| (id, site))
+    ) -> impl Iterator<Item = (CounterId, BasicCoverageBlock)> + Captures<'_> {
+        self.phys_counter_for_node.iter().map(|(&site, &id)| (id, site))
     }
 
     /// Returns an iterator over the subset of BCB nodes that have been associated
@@ -193,93 +223,13 @@ impl CoverageCounters {
     ) -> impl Iterator<Item = (BasicCoverageBlock, ExpressionId)> + Captures<'_> {
         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)),
+            Some(CovTerm::Expression(id)) => Some((bcb, id)),
             // This BCB is associated with a counter or nothing, so skip it.
-            Some(BcbCounter::Counter { .. }) | None => None,
+            Some(CovTerm::Counter { .. } | CovTerm::Zero) | None => None,
         })
     }
 
     pub(super) fn into_expressions(self) -> IndexVec<ExpressionId, Expression> {
-        let old_len = self.expressions.len();
-        let expressions = self
-            .expressions
-            .into_iter()
-            .map(|BcbExpression { lhs, op, rhs }| Expression {
-                lhs: lhs.as_term(),
-                op,
-                rhs: rhs.as_term(),
-            })
-            .collect::<IndexVec<ExpressionId, _>>();
-
-        // Expression IDs are indexes into this vector, so make sure we didn't
-        // accidentally invalidate them by changing its length.
-        assert_eq!(old_len, expressions.len());
-        expressions
-    }
-}
-
-struct Transcriber {
-    old: NodeCounters<BasicCoverageBlock>,
-    new: CoverageCounters,
-    phys_counter_for_site: FxHashMap<Site, BcbCounter>,
-}
-
-impl Transcriber {
-    fn new(num_nodes: usize, old: NodeCounters<BasicCoverageBlock>) -> Self {
-        Self {
-            old,
-            new: CoverageCounters::with_num_bcbs(num_nodes),
-            phys_counter_for_site: FxHashMap::default(),
-        }
-    }
-
-    fn transcribe_counters(
-        mut self,
-        bcb_needs_counter: &DenseBitSet<BasicCoverageBlock>,
-    ) -> CoverageCounters {
-        for bcb in bcb_needs_counter.iter() {
-            let site = Site::Node { bcb };
-            let (mut pos, mut neg): (Vec<_>, Vec<_>) =
-                self.old.counter_expr(bcb).iter().partition_map(
-                    |&CounterTerm { node, op }| match op {
-                        Op::Add => Either::Left(node),
-                        Op::Subtract => Either::Right(node),
-                    },
-                );
-
-            if pos.is_empty() {
-                // If we somehow end up with no positive terms, fall back to
-                // creating a physical counter. There's no known way for this
-                // to happen, but we can avoid an ICE if it does.
-                debug_assert!(false, "{site:?} has no positive counter terms");
-                pos = vec![bcb];
-                neg = vec![];
-            }
-
-            pos.sort();
-            neg.sort();
-
-            let mut new_counters_for_sites = |sites: Vec<BasicCoverageBlock>| {
-                sites
-                    .into_iter()
-                    .map(|node| self.ensure_phys_counter(Site::Node { bcb: node }))
-                    .collect::<Vec<_>>()
-            };
-            let mut pos = new_counters_for_sites(pos);
-            let mut neg = new_counters_for_sites(neg);
-
-            pos.sort();
-            neg.sort();
-
-            let pos_counter = self.new.make_sum(&pos).expect("`pos` should not be empty");
-            let new_counter = self.new.make_subtracted_sum(pos_counter, &neg);
-            self.new.set_node_counter(bcb, new_counter);
-        }
-
-        self.new
-    }
-
-    fn ensure_phys_counter(&mut self, site: Site) -> BcbCounter {
-        *self.phys_counter_for_site.entry(site).or_insert_with(|| self.new.make_phys_counter(site))
+        self.expressions
     }
 }
diff --git a/compiler/rustc_mir_transform/src/coverage/mod.rs b/compiler/rustc_mir_transform/src/coverage/mod.rs
index b1b609595b74a..19568735df76e 100644
--- a/compiler/rustc_mir_transform/src/coverage/mod.rs
+++ b/compiler/rustc_mir_transform/src/coverage/mod.rs
@@ -21,7 +21,7 @@ use rustc_span::Span;
 use rustc_span::def_id::LocalDefId;
 use tracing::{debug, debug_span, trace};
 
-use crate::coverage::counters::{CoverageCounters, Site};
+use crate::coverage::counters::CoverageCounters;
 use crate::coverage::graph::CoverageGraph;
 use crate::coverage::mappings::ExtractedMappings;
 
@@ -89,8 +89,7 @@ fn instrument_function_for_coverage<'tcx>(tcx: TyCtxt<'tcx>, mir_body: &mut mir:
         return;
     }
 
-    let coverage_counters =
-        CoverageCounters::make_bcb_counters(&graph, &bcbs_with_counter_mappings);
+    let coverage_counters = counters::make_bcb_counters(&graph, &bcbs_with_counter_mappings);
 
     let mappings = create_mappings(&extracted_mappings, &coverage_counters);
     if mappings.is_empty() {
@@ -239,14 +238,8 @@ fn inject_coverage_statements<'tcx>(
     coverage_counters: &CoverageCounters,
 ) {
     // Inject counter-increment statements into MIR.
-    for (id, site) in coverage_counters.counter_increment_sites() {
-        // Determine the block to inject a counter-increment statement into.
-        // For BCB nodes this is just their first block, but for edges we need
-        // to create a new block between the two BCBs, and inject into that.
-        let target_bb = match site {
-            Site::Node { bcb } => graph[bcb].leader_bb(),
-        };
-
+    for (id, bcb) in coverage_counters.counter_increment_sites() {
+        let target_bb = graph[bcb].leader_bb();
         inject_statement(mir_body, CoverageKind::CounterIncrement { id }, target_bb);
     }
 
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index dc26d4de57a7c..28829096bca73 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -1,3 +1,5 @@
+use std::cmp::Reverse;
+
 use rustc_ast::expand::StrippedCfgItem;
 use rustc_ast::ptr::P;
 use rustc_ast::visit::{self, Visitor};
@@ -2243,13 +2245,13 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     ) -> Option<(Vec<Segment>, Option<String>)> {
         debug!("make_path_suggestion: span={:?} path={:?}", span, path);
 
-        match (path.get(0), path.get(1)) {
+        match path[..] {
             // `{{root}}::ident::...` on both editions.
             // On 2015 `{{root}}` is usually added implicitly.
-            (Some(fst), Some(snd))
+            [fst, snd, ..]
                 if fst.ident.name == kw::PathRoot && !snd.ident.is_path_segment_keyword() => {}
             // `ident::...` on 2018.
-            (Some(fst), _)
+            [fst, ..]
                 if fst.ident.span.at_least_rust_2018() && !fst.ident.is_path_segment_keyword() =>
             {
                 // Insert a placeholder that's later replaced by `self`/`super`/etc.
@@ -2357,7 +2359,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // 2) `std` suggestions before `core` suggestions.
         let mut extern_crate_names =
             self.extern_prelude.keys().map(|ident| ident.name).collect::<Vec<_>>();
-        extern_crate_names.sort_by(|a, b| b.as_str().partial_cmp(a.as_str()).unwrap());
+        extern_crate_names.sort_by_key(|&name| Reverse(name));
 
         for name in extern_crate_names.into_iter() {
             // Replace first ident with a crate name and check if that is valid.
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index c4aeaf478bd10..1a0292ebbde63 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -3960,7 +3960,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         match res {
             Res::SelfCtor(_) // See #70549.
             | Res::Def(
-                DefKind::Ctor(_, CtorKind::Const) | DefKind::Const | DefKind::ConstParam,
+                DefKind::Ctor(_, CtorKind::Const) | DefKind::Const | DefKind::AssocConst | DefKind::ConstParam,
                 _,
             ) if is_syntactic_ambiguity => {
                 // Disambiguate in favor of a unit struct/variant or constant pattern.
@@ -3969,7 +3969,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                 }
                 Some(res)
             }
-            Res::Def(DefKind::Ctor(..) | DefKind::Const | DefKind::Static { .. }, _) => {
+            Res::Def(DefKind::Ctor(..) | DefKind::Const | DefKind::AssocConst | DefKind::Static { .. }, _) => {
                 // This is unambiguously a fresh binding, either syntactically
                 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
                 // to something unusable as a pattern (e.g., constructor function),
@@ -4005,7 +4005,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                 );
                 None
             }
-            Res::Def(DefKind::Fn, _) | Res::Local(..) | Res::Err => {
+            Res::Def(DefKind::Fn | DefKind::AssocFn, _) | Res::Local(..) | Res::Err => {
                 // These entities are explicitly allowed to be shadowed by fresh bindings.
                 None
             }
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs
index fc0de13aeab09..b4d294a70c071 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs
@@ -172,14 +172,14 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         let bound_predicate = predicate.kind();
         let mut err = match bound_predicate.skip_binder() {
             ty::PredicateKind::Clause(ty::ClauseKind::Trait(data)) => {
-                let trait_ref = bound_predicate.rebind(data.trait_ref);
-                debug!(?trait_ref);
+                let trait_pred = bound_predicate.rebind(data);
+                debug!(?trait_pred);
 
                 if let Err(e) = predicate.error_reported() {
                     return e;
                 }
 
-                if let Err(guar) = self.tcx.ensure().coherent_trait(trait_ref.def_id()) {
+                if let Err(guar) = self.tcx.ensure().coherent_trait(trait_pred.def_id()) {
                     // Avoid bogus "type annotations needed `Foo: Bar`" errors on `impl Bar for Foo` in case
                     // other `Foo` impls are incoherent.
                     return guar;
@@ -200,13 +200,13 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 // avoid inundating the user with unnecessary errors, but we now
                 // check upstream for type errors and don't add the obligations to
                 // begin with in those cases.
-                if self.tcx.is_lang_item(trait_ref.def_id(), LangItem::Sized) {
+                if self.tcx.is_lang_item(trait_pred.def_id(), LangItem::Sized) {
                     match self.tainted_by_errors() {
                         None => {
                             let err = self.emit_inference_failure_err(
                                 obligation.cause.body_id,
                                 span,
-                                trait_ref.self_ty().skip_binder().into(),
+                                trait_pred.self_ty().skip_binder().into(),
                                 TypeAnnotationNeeded::E0282,
                                 false,
                             );
@@ -251,10 +251,14 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 
                 let mut ambiguities = compute_applicable_impls_for_diagnostics(
                     self.infcx,
-                    &obligation.with(self.tcx, trait_ref),
+                    &obligation.with(self.tcx, trait_pred),
                 );
-                let has_non_region_infer =
-                    trait_ref.skip_binder().args.types().any(|t| !t.is_ty_or_numeric_infer());
+                let has_non_region_infer = trait_pred
+                    .skip_binder()
+                    .trait_ref
+                    .args
+                    .types()
+                    .any(|t| !t.is_ty_or_numeric_infer());
                 // It doesn't make sense to talk about applicable impls if there are more than a
                 // handful of them. If there are a lot of them, but only a few of them have no type
                 // params, we only show those, as they are more likely to be useful/intended.
@@ -294,7 +298,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     if impl_candidates.len() < 40 {
                         self.report_similar_impl_candidates(
                             impl_candidates.as_slice(),
-                            trait_ref,
+                            trait_pred,
                             obligation.cause.body_id,
                             &mut err,
                             false,
@@ -306,7 +310,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 if let ObligationCauseCode::WhereClause(def_id, _)
                 | ObligationCauseCode::WhereClauseInExpr(def_id, ..) = *obligation.cause.code()
                 {
-                    self.suggest_fully_qualified_path(&mut err, def_id, span, trait_ref.def_id());
+                    self.suggest_fully_qualified_path(&mut err, def_id, span, trait_pred.def_id());
                 }
 
                 if let Some(ty::GenericArgKind::Type(_)) = arg.map(|arg| arg.unpack())
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
index 6076c999086bf..c40ba33084569 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
@@ -23,9 +23,7 @@ use rustc_middle::ty::print::{
     FmtPrinter, Print, PrintPolyTraitPredicateExt, PrintTraitPredicateExt as _,
     PrintTraitRefExt as _, with_forced_trimmed_paths,
 };
-use rustc_middle::ty::{
-    self, ToPolyTraitRef, TraitRef, Ty, TyCtxt, TypeFoldable, TypeVisitableExt, Upcast,
-};
+use rustc_middle::ty::{self, TraitRef, Ty, TyCtxt, TypeFoldable, TypeVisitableExt, Upcast};
 use rustc_middle::{bug, span_bug};
 use rustc_span::{BytePos, DUMMY_SP, STDLIB_STABLE_CRATES, Span, Symbol, sym};
 use tracing::{debug, instrument};
@@ -155,12 +153,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             (leaf_trait_predicate, &obligation)
                         };
 
-                        let main_trait_ref = main_trait_predicate.to_poly_trait_ref();
-                        let leaf_trait_ref = leaf_trait_predicate.to_poly_trait_ref();
-
                         if let Some(guar) = self.emit_specialized_closure_kind_error(
                             &obligation,
-                            leaf_trait_ref,
+                            leaf_trait_predicate,
                         ) {
                             return guar;
                         }
@@ -202,14 +197,14 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         } = self.on_unimplemented_note(main_trait_predicate, main_obligation, &mut long_ty_file);
 
                         let have_alt_message = message.is_some() || label.is_some();
-                        let is_try_conversion = self.is_try_conversion(span, main_trait_ref.def_id());
+                        let is_try_conversion = self.is_try_conversion(span, main_trait_predicate.def_id());
                         let is_unsize =
-                            self.tcx.is_lang_item(leaf_trait_ref.def_id(), LangItem::Unsize);
+                            self.tcx.is_lang_item(leaf_trait_predicate.def_id(), LangItem::Unsize);
                         let (message, notes, append_const_msg) = if is_try_conversion {
                             (
                                 Some(format!(
                                     "`?` couldn't convert the error to `{}`",
-                                    main_trait_ref.skip_binder().self_ty(),
+                                    main_trait_predicate.skip_binder().self_ty(),
                                 )),
                                 vec![
                                     "the question mark operation (`?`) implicitly performs a \
@@ -230,12 +225,12 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             post_message,
                         );
 
-                        let (err_msg, safe_transmute_explanation) = if self.tcx.is_lang_item(main_trait_ref.def_id(), LangItem::TransmuteTrait)
+                        let (err_msg, safe_transmute_explanation) = if self.tcx.is_lang_item(main_trait_predicate.def_id(), LangItem::TransmuteTrait)
                         {
                             // Recompute the safe transmute reason and use that for the error reporting
                             match self.get_safe_transmute_error_and_reason(
                                 obligation.clone(),
-                                main_trait_ref,
+                                main_trait_predicate,
                                 span,
                             ) {
                                 GetSafeTransmuteErrorAndReason::Silent => {
@@ -266,7 +261,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         }
                         let mut suggested = false;
                         if is_try_conversion {
-                            suggested = self.try_conversion_context(&obligation, main_trait_ref.skip_binder(), &mut err);
+                            suggested = self.try_conversion_context(&obligation, main_trait_predicate, &mut err);
                         }
 
                         if is_try_conversion && let Some(ret_span) = self.return_type_span(&obligation) {
@@ -274,12 +269,12 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                                 ret_span,
                                 format!(
                                     "expected `{}` because of this",
-                                    main_trait_ref.skip_binder().self_ty()
+                                    main_trait_predicate.skip_binder().self_ty()
                                 ),
                             );
                         }
 
-                        if tcx.is_lang_item(leaf_trait_ref.def_id(), LangItem::Tuple) {
+                        if tcx.is_lang_item(leaf_trait_predicate.def_id(), LangItem::Tuple) {
                             self.add_tuple_trait_message(
                                 obligation.cause.code().peel_derives(),
                                 &mut err,
@@ -319,7 +314,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             // If it has a custom `#[rustc_on_unimplemented]`
                             // error message, let's display it as the label!
                             err.span_label(span, s);
-                            if !matches!(leaf_trait_ref.skip_binder().self_ty().kind(), ty::Param(_)) {
+                            if !matches!(leaf_trait_predicate.skip_binder().self_ty().kind(), ty::Param(_)) {
                                 // When the self type is a type param We don't need to "the trait
                                 // `std::marker::Sized` is not implemented for `T`" as we will point
                                 // at the type param with a label to suggest constraining it.
@@ -339,7 +334,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         if let ObligationCauseCode::Coercion { source, target } =
                             *obligation.cause.code().peel_derives()
                         {
-                            if self.tcx.is_lang_item(leaf_trait_ref.def_id(), LangItem::Sized) {
+                            if self.tcx.is_lang_item(leaf_trait_predicate.def_id(), LangItem::Sized) {
                                 self.suggest_borrowing_for_object_cast(
                                     &mut err,
                                     root_obligation,
@@ -368,7 +363,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             err.span_label(tcx.def_span(body), s);
                         }
 
-                        self.suggest_floating_point_literal(&obligation, &mut err, leaf_trait_ref);
+                        self.suggest_floating_point_literal(&obligation, &mut err, leaf_trait_predicate);
                         self.suggest_dereferencing_index(&obligation, &mut err, leaf_trait_predicate);
                         suggested |= self.suggest_dereferences(&obligation, &mut err, leaf_trait_predicate);
                         suggested |= self.suggest_fn_call(&obligation, &mut err, leaf_trait_predicate);
@@ -376,7 +371,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         suggested = if let &[cand] = &impl_candidates[..] {
                             let cand = cand.trait_ref;
                             if let (ty::FnPtr(..), ty::FnDef(..)) =
-                                (cand.self_ty().kind(), main_trait_ref.self_ty().skip_binder().kind())
+                                (cand.self_ty().kind(), main_trait_predicate.self_ty().skip_binder().kind())
                             {
                                 // Wrap method receivers and `&`-references in parens
                                 let suggestion = if self.tcx.sess.source_map().span_look_ahead(span, ".", Some(50)).is_some() {
@@ -423,11 +418,11 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             span,
                             leaf_trait_predicate,
                         );
-                        self.note_version_mismatch(&mut err, leaf_trait_ref);
+                        self.note_version_mismatch(&mut err, leaf_trait_predicate);
                         self.suggest_remove_await(&obligation, &mut err);
                         self.suggest_derive(&obligation, &mut err, leaf_trait_predicate);
 
-                        if tcx.is_lang_item(leaf_trait_ref.def_id(), LangItem::Try) {
+                        if tcx.is_lang_item(leaf_trait_predicate.def_id(), LangItem::Try) {
                             self.suggest_await_before_try(
                                 &mut err,
                                 &obligation,
@@ -455,9 +450,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             );
                         }
 
-                        let is_fn_trait = tcx.is_fn_trait(leaf_trait_ref.def_id());
+                        let is_fn_trait = tcx.is_fn_trait(leaf_trait_predicate.def_id());
                         let is_target_feature_fn = if let ty::FnDef(def_id, _) =
-                            *leaf_trait_ref.skip_binder().self_ty().kind()
+                            *leaf_trait_predicate.skip_binder().self_ty().kind()
                         {
                             !self.tcx.codegen_fn_attrs(def_id).target_features.is_empty()
                         } else {
@@ -509,7 +504,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         }
 
                         self.explain_hrtb_projection(&mut err, leaf_trait_predicate, obligation.param_env, &obligation.cause);
-                        self.suggest_desugaring_async_fn_in_trait(&mut err, main_trait_ref);
+                        self.suggest_desugaring_async_fn_in_trait(&mut err, main_trait_predicate);
 
                         // Return early if the trait is Debug or Display and the invocation
                         // originates within a standard library macro, because the output
@@ -527,7 +522,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 
                         if in_std_macro
                             && matches!(
-                                self.tcx.get_diagnostic_name(leaf_trait_ref.def_id()),
+                                self.tcx.get_diagnostic_name(leaf_trait_predicate.def_id()),
                                 Some(sym::Debug | sym::Display)
                             )
                         {
@@ -785,21 +780,22 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     fn emit_specialized_closure_kind_error(
         &self,
         obligation: &PredicateObligation<'tcx>,
-        mut trait_ref: ty::PolyTraitRef<'tcx>,
+        mut trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) -> Option<ErrorGuaranteed> {
         // If `AsyncFnKindHelper` is not implemented, that means that the closure kind
         // doesn't extend the goal kind. This is worth reporting, but we can only do so
         // if we actually know which closure this goal comes from, so look at the cause
         // to see if we can extract that information.
-        if self.tcx.is_lang_item(trait_ref.def_id(), LangItem::AsyncFnKindHelper)
-            && let Some(found_kind) = trait_ref.skip_binder().args.type_at(0).to_opt_closure_kind()
+        if self.tcx.is_lang_item(trait_pred.def_id(), LangItem::AsyncFnKindHelper)
+            && let Some(found_kind) =
+                trait_pred.skip_binder().trait_ref.args.type_at(0).to_opt_closure_kind()
             && let Some(expected_kind) =
-                trait_ref.skip_binder().args.type_at(1).to_opt_closure_kind()
+                trait_pred.skip_binder().trait_ref.args.type_at(1).to_opt_closure_kind()
             && !found_kind.extends(expected_kind)
         {
             if let Some((_, Some(parent))) = obligation.cause.code().parent_with_predicate() {
                 // If we have a derived obligation, then the parent will be a `AsyncFn*` goal.
-                trait_ref = parent.to_poly_trait_ref();
+                trait_pred = parent;
             } else if let &ObligationCauseCode::FunctionArg { arg_hir_id, .. } =
                 obligation.cause.code()
                 && let Some(typeck_results) = &self.typeck_results
@@ -820,9 +816,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             }
         }
 
-        let self_ty = trait_ref.self_ty().skip_binder();
+        let self_ty = trait_pred.self_ty().skip_binder();
 
-        if let Some(expected_kind) = self.tcx.fn_trait_kind_from_def_id(trait_ref.def_id()) {
+        if let Some(expected_kind) = self.tcx.fn_trait_kind_from_def_id(trait_pred.def_id()) {
             let (closure_def_id, found_args, by_ref_captures) = match *self_ty.kind() {
                 ty::Closure(def_id, args) => {
                     (def_id, args.as_closure().sig().map_bound(|sig| sig.inputs()[0]), None)
@@ -837,7 +833,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 _ => return None,
             };
 
-            let expected_args = trait_ref.map_bound(|trait_ref| trait_ref.args.type_at(1));
+            let expected_args =
+                trait_pred.map_bound(|trait_pred| trait_pred.trait_ref.args.type_at(1));
 
             // Verify that the arguments are compatible. If the signature is
             // mismatched, then we have a totally different error to report.
@@ -909,7 +906,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     fn try_conversion_context(
         &self,
         obligation: &PredicateObligation<'tcx>,
-        trait_ref: ty::TraitRef<'tcx>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
         err: &mut Diag<'_>,
     ) -> bool {
         let span = obligation.cause.span;
@@ -953,8 +950,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         if !self.tcx.is_diagnostic_item(sym::FromResidual, y.def_id()) {
             return false;
         }
-        let self_ty = trait_ref.self_ty();
-        let found_ty = trait_ref.args.get(1).and_then(|a| a.as_type());
+        let self_ty = trait_pred.skip_binder().self_ty();
+        let found_ty = trait_pred.skip_binder().trait_ref.args.get(1).and_then(|a| a.as_type());
 
         let mut prev_ty = self.resolve_vars_if_possible(
             typeck.expr_ty_adjusted_opt(expr).unwrap_or(Ty::new_misc_error(self.tcx)),
@@ -1223,18 +1220,18 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         goal: ty::TraitPredicate<'tcx>,
         assumption: ty::PolyTraitPredicate<'tcx>,
     ) -> bool {
+        // Fast path
         if goal.polarity != assumption.polarity() {
             return false;
         }
 
-        let trait_goal = goal.trait_ref;
         let trait_assumption = self.instantiate_binder_with_fresh_vars(
             DUMMY_SP,
             infer::BoundRegionConversionTime::HigherRankedType,
-            assumption.to_poly_trait_ref(),
+            assumption,
         );
 
-        self.can_eq(ty::ParamEnv::empty(), trait_goal, trait_assumption)
+        self.can_eq(ty::ParamEnv::empty(), goal.trait_ref, trait_assumption.trait_ref)
     }
 
     fn can_match_projection(
@@ -1682,7 +1679,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     pub(super) fn report_similar_impl_candidates(
         &self,
         impl_candidates: &[ImplCandidate<'tcx>],
-        trait_ref: ty::PolyTraitRef<'tcx>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
         body_def_id: LocalDefId,
         err: &mut Diag<'_>,
         other: bool,
@@ -1727,7 +1724,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         // We'll check for the case where the reason for the mismatch is that the trait comes from
         // one crate version and the type comes from another crate version, even though they both
         // are from the same crate.
-        let trait_def_id = trait_ref.def_id();
+        let trait_def_id = trait_pred.def_id();
         let trait_name = self.tcx.item_name(trait_def_id);
         let crate_name = self.tcx.crate_name(trait_def_id.krate);
         if let Some(other_trait_def_id) = self.tcx.all_traits().find(|def_id| {
@@ -1739,7 +1736,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             // different crate `DefId`. We highlight the traits.
 
             let found_type =
-                if let ty::Adt(def, _) = trait_ref.self_ty().skip_binder().peel_refs().kind() {
+                if let ty::Adt(def, _) = trait_pred.self_ty().skip_binder().peel_refs().kind() {
                     Some(def.did())
                 } else {
                     None
@@ -1836,7 +1833,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             if self.probe(|_| {
                 let ocx = ObligationCtxt::new(self);
 
-                self.enter_forall(trait_ref, |obligation_trait_ref| {
+                self.enter_forall(trait_pred, |obligation_trait_ref| {
                     let impl_args = self.fresh_args_for_item(DUMMY_SP, single.impl_def_id);
                     let impl_trait_ref = ocx.normalize(
                         &ObligationCause::dummy(),
@@ -1864,7 +1861,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 
                     let mut terrs = vec![];
                     for (obligation_arg, impl_arg) in
-                        std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args)
+                        std::iter::zip(obligation_trait_ref.trait_ref.args, impl_trait_ref.args)
                     {
                         if (obligation_arg, impl_arg).references_error() {
                             return false;
@@ -1906,8 +1903,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     }
 
                     let traits = self.cmp_traits(
-                        obligation_trait_ref.def_id,
-                        &obligation_trait_ref.args[1..],
+                        obligation_trait_ref.def_id(),
+                        &obligation_trait_ref.trait_ref.args[1..],
                         impl_trait_ref.def_id,
                         &impl_trait_ref.args[1..],
                     );
@@ -1991,7 +1988,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             }
             if let &[cand] = &candidates[..] {
                 let (desc, mention_castable) =
-                    match (cand.self_ty().kind(), trait_ref.self_ty().skip_binder().kind()) {
+                    match (cand.self_ty().kind(), trait_pred.self_ty().skip_binder().kind()) {
                         (ty::FnPtr(..), ty::FnDef(..)) => {
                             (" implemented for fn pointer `", ", cast using `as`")
                         }
@@ -2055,7 +2052,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             .filter(|cand| !self.tcx.do_not_recommend_impl(cand.impl_def_id))
             .collect::<Vec<_>>();
 
-        let def_id = trait_ref.def_id();
+        let def_id = trait_pred.def_id();
         if impl_candidates.is_empty() {
             if self.tcx.trait_is_auto(def_id)
                 || self.tcx.lang_items().iter().any(|(_, id)| id == def_id)
@@ -2132,11 +2129,10 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             && !self.tcx.trait_is_auto(def_id)
             && !self.tcx.lang_items().iter().any(|(_, id)| id == def_id)
         {
-            let trait_ref = trait_pred.to_poly_trait_ref();
             let impl_candidates = self.find_similar_impl_candidates(trait_pred);
             self.report_similar_impl_candidates(
                 &impl_candidates,
-                trait_ref,
+                trait_pred,
                 body_def_id,
                 err,
                 true,
@@ -2173,12 +2169,16 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     /// If the `Self` type of the unsatisfied trait `trait_ref` implements a trait
     /// with the same path as `trait_ref`, a help message about
     /// a probable version mismatch is added to `err`
-    fn note_version_mismatch(&self, err: &mut Diag<'_>, trait_ref: ty::PolyTraitRef<'tcx>) -> bool {
+    fn note_version_mismatch(
+        &self,
+        err: &mut Diag<'_>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
+    ) -> bool {
         let get_trait_impls = |trait_def_id| {
             let mut trait_impls = vec![];
             self.tcx.for_each_relevant_impl(
                 trait_def_id,
-                trait_ref.skip_binder().self_ty(),
+                trait_pred.skip_binder().self_ty(),
                 |impl_def_id| {
                     trait_impls.push(impl_def_id);
                 },
@@ -2186,11 +2186,11 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             trait_impls
         };
 
-        let required_trait_path = self.tcx.def_path_str(trait_ref.def_id());
+        let required_trait_path = self.tcx.def_path_str(trait_pred.def_id());
         let traits_with_same_path: UnordSet<_> = self
             .tcx
             .visible_traits()
-            .filter(|trait_def_id| *trait_def_id != trait_ref.def_id())
+            .filter(|trait_def_id| *trait_def_id != trait_pred.def_id())
             .map(|trait_def_id| (self.tcx.def_path_str(trait_def_id), trait_def_id))
             .filter(|(p, _)| *p == required_trait_path)
             .collect();
@@ -2374,7 +2374,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     fn get_safe_transmute_error_and_reason(
         &self,
         obligation: PredicateObligation<'tcx>,
-        trait_ref: ty::PolyTraitRef<'tcx>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
         span: Span,
     ) -> GetSafeTransmuteErrorAndReason {
         use rustc_transmute::Answer;
@@ -2386,19 +2386,19 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             }
 
             // Erase regions because layout code doesn't particularly care about regions.
-            let trait_ref =
-                self.tcx.erase_regions(self.tcx.instantiate_bound_regions_with_erased(trait_ref));
+            let trait_pred =
+                self.tcx.erase_regions(self.tcx.instantiate_bound_regions_with_erased(trait_pred));
 
             let src_and_dst = rustc_transmute::Types {
-                dst: trait_ref.args.type_at(0),
-                src: trait_ref.args.type_at(1),
+                dst: trait_pred.trait_ref.args.type_at(0),
+                src: trait_pred.trait_ref.args.type_at(1),
             };
 
             let ocx = ObligationCtxt::new(self);
             let Ok(assume) = ocx.structurally_normalize_const(
                 &obligation.cause,
                 obligation.param_env,
-                trait_ref.args.const_at(2),
+                trait_pred.trait_ref.args.const_at(2),
             ) else {
                 self.dcx().span_delayed_bug(
                     span,
@@ -2417,8 +2417,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 return GetSafeTransmuteErrorAndReason::Silent;
             };
 
-            let dst = trait_ref.args.type_at(0);
-            let src = trait_ref.args.type_at(1);
+            let dst = trait_pred.trait_ref.args.type_at(0);
+            let src = trait_pred.trait_ref.args.type_at(1);
             let err_msg = format!("`{src}` cannot be safely transmuted into `{dst}`");
 
             match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable(
@@ -2566,12 +2566,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 trait_predicate.skip_binder().polarity,
             )
         {
-            self.add_help_message_for_fn_trait(
-                trait_predicate.to_poly_trait_ref(),
-                err,
-                implemented_kind,
-                params,
-            );
+            self.add_help_message_for_fn_trait(trait_predicate, err, implemented_kind, params);
         } else if !trait_predicate.has_non_region_infer()
             && self.predicate_can_apply(obligation.param_env, trait_predicate)
         {
@@ -2606,7 +2601,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             let impl_candidates = self.find_similar_impl_candidates(trait_predicate);
             if !self.report_similar_impl_candidates(
                 &impl_candidates,
-                trait_predicate.to_poly_trait_ref(),
+                trait_predicate,
                 body_def_id,
                 err,
                 true,
@@ -2623,7 +2618,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             self.suggest_convert_to_slice(
                 err,
                 obligation,
-                trait_predicate.to_poly_trait_ref(),
+                trait_predicate,
                 impl_candidates.as_slice(),
                 span,
             );
@@ -2634,7 +2629,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 
     fn add_help_message_for_fn_trait(
         &self,
-        trait_ref: ty::PolyTraitRef<'tcx>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
         err: &mut Diag<'_>,
         implemented_kind: ty::ClosureKind,
         params: ty::Binder<'tcx, Ty<'tcx>>,
@@ -2647,12 +2642,12 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         // to implement.
         let selected_kind = self
             .tcx
-            .fn_trait_kind_from_def_id(trait_ref.def_id())
+            .fn_trait_kind_from_def_id(trait_pred.def_id())
             .expect("expected to map DefId to ClosureKind");
         if !implemented_kind.extends(selected_kind) {
             err.note(format!(
                 "`{}` implements `{}`, but it must implement `{}`, which is more general",
-                trait_ref.skip_binder().self_ty(),
+                trait_pred.skip_binder().self_ty(),
                 implemented_kind,
                 selected_kind
             ));
@@ -2660,7 +2655,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 
         // Note any argument mismatches
         let given_ty = params.skip_binder();
-        let expected_ty = trait_ref.skip_binder().args.type_at(1);
+        let expected_ty = trait_pred.skip_binder().trait_ref.args.type_at(1);
         if let ty::Tuple(given) = given_ty.kind()
             && let ty::Tuple(expected) = expected_ty.kind()
         {
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
index 2d248d00066e0..2d932e36470e2 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
@@ -10,7 +10,7 @@ use rustc_hir::{AttrArgs, AttrKind, Attribute};
 use rustc_macros::LintDiagnostic;
 use rustc_middle::bug;
 use rustc_middle::ty::print::PrintTraitRefExt as _;
-use rustc_middle::ty::{self, GenericArgsRef, GenericParamDefKind, ToPolyTraitRef, TyCtxt};
+use rustc_middle::ty::{self, GenericArgsRef, GenericParamDefKind, TyCtxt};
 use rustc_parse_format::{ParseMode, Parser, Piece, Position};
 use rustc_session::lint::builtin::UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES;
 use rustc_span::{Span, Symbol, kw, sym};
@@ -42,18 +42,18 @@ static ALLOWED_FORMAT_SYMBOLS: &[Symbol] = &[
 impl<'tcx> TypeErrCtxt<'_, 'tcx> {
     fn impl_similar_to(
         &self,
-        trait_ref: ty::PolyTraitRef<'tcx>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
         obligation: &PredicateObligation<'tcx>,
     ) -> Option<(DefId, GenericArgsRef<'tcx>)> {
         let tcx = self.tcx;
         let param_env = obligation.param_env;
-        self.enter_forall(trait_ref, |trait_ref| {
-            let trait_self_ty = trait_ref.self_ty();
+        self.enter_forall(trait_pred, |trait_pred| {
+            let trait_self_ty = trait_pred.self_ty();
 
             let mut self_match_impls = vec![];
             let mut fuzzy_match_impls = vec![];
 
-            self.tcx.for_each_relevant_impl(trait_ref.def_id, trait_self_ty, |def_id| {
+            self.tcx.for_each_relevant_impl(trait_pred.def_id(), trait_self_ty, |def_id| {
                 let impl_args = self.fresh_args_for_item(obligation.cause.span, def_id);
                 let impl_trait_ref =
                     tcx.impl_trait_ref(def_id).unwrap().instantiate(tcx, impl_args);
@@ -64,7 +64,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     self_match_impls.push((def_id, impl_args));
 
                     if iter::zip(
-                        trait_ref.args.types().skip(1),
+                        trait_pred.trait_ref.args.types().skip(1),
                         impl_trait_ref.args.types().skip(1),
                     )
                     .all(|(u, v)| self.fuzzy_match_tys(u, v, false).is_some())
@@ -117,7 +117,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         }
 
         let (def_id, args) = self
-            .impl_similar_to(trait_pred.to_poly_trait_ref(), obligation)
+            .impl_similar_to(trait_pred, obligation)
             .unwrap_or_else(|| (trait_pred.def_id(), trait_pred.skip_binder().trait_ref.args));
         let trait_pred = trait_pred.skip_binder();
 
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
index 9d85ca1dd4dd7..c2e73b732d314 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
@@ -32,9 +32,9 @@ use rustc_middle::ty::print::{
     with_forced_trimmed_paths, with_no_trimmed_paths,
 };
 use rustc_middle::ty::{
-    self, AdtKind, GenericArgs, InferTy, IsSuggestable, ToPolyTraitRef, Ty, TyCtxt, TypeFoldable,
-    TypeFolder, TypeSuperFoldable, TypeVisitableExt, TypeckResults, Upcast,
-    suggest_arbitrary_trait_bound, suggest_constraining_type_param,
+    self, AdtKind, GenericArgs, InferTy, IsSuggestable, Ty, TyCtxt, TypeFoldable, TypeFolder,
+    TypeSuperFoldable, TypeVisitableExt, TypeckResults, Upcast, suggest_arbitrary_trait_bound,
+    suggest_constraining_type_param,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_span::def_id::LocalDefId;
@@ -218,15 +218,15 @@ pub fn suggest_restriction<'tcx, G: EmissionGuarantee>(
             (_, None) => predicate_constraint(hir_generics, trait_pred.upcast(tcx)),
             (None, Some((ident, []))) => (
                 ident.span.shrink_to_hi(),
-                format!(": {}", trait_pred.to_poly_trait_ref().print_trait_sugared()),
+                format!(": {}", trait_pred.print_modifiers_and_trait_path()),
             ),
             (_, Some((_, [.., bounds]))) => (
                 bounds.span().shrink_to_hi(),
-                format!(" + {}", trait_pred.to_poly_trait_ref().print_trait_sugared()),
+                format!(" + {}", trait_pred.print_modifiers_and_trait_path()),
             ),
             (Some(_), Some((_, []))) => (
                 hir_generics.span.shrink_to_hi(),
-                format!(": {}", trait_pred.to_poly_trait_ref().print_trait_sugared()),
+                format!(": {}", trait_pred.print_modifiers_and_trait_path()),
             ),
         };
 
@@ -3729,7 +3729,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         &self,
         obligation: &PredicateObligation<'tcx>,
         err: &mut Diag<'_>,
-        trait_ref: ty::PolyTraitRef<'tcx>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) {
         let rhs_span = match obligation.cause.code() {
             ObligationCauseCode::BinOp { rhs_span: Some(span), rhs_is_lit, .. } if *rhs_is_lit => {
@@ -3737,8 +3737,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             }
             _ => return,
         };
-        if let ty::Float(_) = trait_ref.skip_binder().self_ty().kind()
-            && let ty::Infer(InferTy::IntVar(_)) = trait_ref.skip_binder().args.type_at(1).kind()
+        if let ty::Float(_) = trait_pred.skip_binder().self_ty().kind()
+            && let ty::Infer(InferTy::IntVar(_)) =
+                trait_pred.skip_binder().trait_ref.args.type_at(1).kind()
         {
             err.span_suggestion_verbose(
                 rhs_span.shrink_to_hi(),
@@ -4448,7 +4449,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         &self,
         err: &mut Diag<'_>,
         obligation: &PredicateObligation<'tcx>,
-        trait_ref: ty::PolyTraitRef<'tcx>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
         candidate_impls: &[ImplCandidate<'tcx>],
         span: Span,
     ) {
@@ -4464,7 +4465,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         // 1. `[T; _]` (array of T)
         // 2. `&[T; _]` (reference to array of T)
         // 3. `&mut [T; _]` (mutable reference to array of T)
-        let (element_ty, mut mutability) = match *trait_ref.skip_binder().self_ty().kind() {
+        let (element_ty, mut mutability) = match *trait_pred.skip_binder().self_ty().kind() {
             ty::Array(element_ty, _) => (element_ty, None),
 
             ty::Ref(_, pointee_ty, mutability) => match *pointee_ty.kind() {
@@ -4620,14 +4621,14 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     pub(super) fn suggest_desugaring_async_fn_in_trait(
         &self,
         err: &mut Diag<'_>,
-        trait_ref: ty::PolyTraitRef<'tcx>,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) {
         // Don't suggest if RTN is active -- we should prefer a where-clause bound instead.
         if self.tcx.features().return_type_notation() {
             return;
         }
 
-        let trait_def_id = trait_ref.def_id();
+        let trait_def_id = trait_pred.def_id();
 
         // Only suggest specifying auto traits
         if !self.tcx.trait_is_auto(trait_def_id) {
@@ -4635,7 +4636,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         }
 
         // Look for an RPITIT
-        let ty::Alias(ty::Projection, alias_ty) = trait_ref.self_ty().skip_binder().kind() else {
+        let ty::Alias(ty::Projection, alias_ty) = trait_pred.self_ty().skip_binder().kind() else {
             return;
         };
         let Some(ty::ImplTraitInTraitData::Trait { fn_def_id, opaque_def_id }) =
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index 968dc631e50e5..b370f802052e7 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -16,7 +16,7 @@ use rustc_infer::traits::{
     Obligation, ObligationCause, PolyTraitObligation, PredicateObligations, SelectionError,
 };
 use rustc_middle::ty::fast_reject::DeepRejectCtxt;
-use rustc_middle::ty::{self, ToPolyTraitRef, Ty, TypeVisitableExt, TypingMode};
+use rustc_middle::ty::{self, Ty, TypeVisitableExt, TypingMode};
 use rustc_middle::{bug, span_bug};
 use rustc_type_ir::Interner;
 use tracing::{debug, instrument, trace};
@@ -186,10 +186,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     }
 
                     selcx.infcx.probe(|_| {
+                        // We checked the polarity already
                         match selcx.match_normalize_trait_ref(
                             obligation,
                             placeholder_trait_predicate.trait_ref,
-                            bound.to_poly_trait_ref(),
+                            bound.map_bound(|pred| pred.trait_ref),
                         ) {
                             Ok(None) => {
                                 candidates.vec.push(ProjectionCandidate(idx));
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 0ccb0fc0615c0..729ae3f2c2a26 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -16,7 +16,7 @@ use rustc_hir::lang_items::LangItem;
 use rustc_infer::infer::{DefineOpaqueTypes, HigherRankedType, InferOk};
 use rustc_infer::traits::ObligationCauseCode;
 use rustc_middle::traits::{BuiltinImplSource, SignatureMismatchData};
-use rustc_middle::ty::{self, GenericArgsRef, ToPolyTraitRef, Ty, TyCtxt, Upcast};
+use rustc_middle::ty::{self, GenericArgsRef, Ty, TyCtxt, Upcast};
 use rustc_middle::{bug, span_bug};
 use rustc_span::def_id::DefId;
 use rustc_type_ir::elaborate;
@@ -458,8 +458,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         ensure_sufficient_stack(|| {
             let cause = obligation.derived_cause(ObligationCauseCode::BuiltinDerived);
 
-            let poly_trait_ref = obligation.predicate.to_poly_trait_ref();
-            let trait_ref = self.infcx.enter_forall_and_leak_universe(poly_trait_ref);
+            assert_eq!(obligation.predicate.polarity(), ty::PredicatePolarity::Positive);
+            let trait_ref =
+                self.infcx.enter_forall_and_leak_universe(obligation.predicate).trait_ref;
             let trait_obligations = self.impl_or_trait_obligations(
                 &cause,
                 obligation.recursion_depth + 1,
diff --git a/src/bootstrap/mk/Makefile.in b/src/bootstrap/mk/Makefile.in
index a1f38b9ac147f..082b7431440ad 100644
--- a/src/bootstrap/mk/Makefile.in
+++ b/src/bootstrap/mk/Makefile.in
@@ -97,6 +97,11 @@ tidy:
 prepare:
 	$(Q)$(BOOTSTRAP) build --stage 2 --dry-run
 
+# Set of tests that represent around half of the time of the test suite.
+# Used to split tests across multiple CI runners.
+STAGE_2_TEST_SET1 := test --stage 2 --skip=compiler --skip=src
+STAGE_2_TEST_SET2 := test --stage 2 --skip=tests --skip=coverage-map --skip=coverage-run --skip=library --skip=tidyselftest
+
 ## MSVC native builders
 
 # this intentionally doesn't use `$(BOOTSTRAP)` so we can test the shebang on Windows
@@ -105,6 +110,10 @@ ci-msvc-py:
 ci-msvc-ps1:
 	$(Q)$(CFG_SRC_DIR)/x.ps1 test --stage 2 --skip tidy
 ci-msvc: ci-msvc-py ci-msvc-ps1
+ci-msvc-py-set1:
+	$(Q)$(CFG_SRC_DIR)/x.py $(STAGE_2_TEST_SET1)
+ci-msvc-ps1-set2:
+	$(Q)$(CFG_SRC_DIR)/x.ps1 $(STAGE_2_TEST_SET2)
 
 ## MingW native builders
 
@@ -112,9 +121,9 @@ ci-msvc: ci-msvc-py ci-msvc-ps1
 # Used to split tests across multiple CI runners.
 # Test both x and bootstrap entrypoints.
 ci-mingw-x:
-	$(Q)$(CFG_SRC_DIR)/x test --stage 2 --skip=compiler --skip=src
+	$(Q)$(CFG_SRC_DIR)/x $(STAGE_2_TEST_SET1)
 ci-mingw-bootstrap:
-	$(Q)$(BOOTSTRAP) test --stage 2 --skip=tests --skip=coverage-map --skip=coverage-run --skip=library --skip=tidyselftest
+	$(Q)$(BOOTSTRAP) $(STAGE_2_TEST_SET2)
 ci-mingw: ci-mingw-x ci-mingw-bootstrap
 
 .PHONY: dist
diff --git a/src/ci/docker/README.md b/src/ci/docker/README.md
index 2f52ff5a99a50..2b1de43c2f68c 100644
--- a/src/ci/docker/README.md
+++ b/src/ci/docker/README.md
@@ -305,8 +305,6 @@ For targets: `mips-unknown-linux-gnu`
 - Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
 - Path and misc options > Use a mirror = ENABLE
 - Path and misc options > Base URL = https://ci-mirrors.rust-lang.org/rustc
-- Path and misc options > Patches origin = Bundled, then local
-- Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = mips
 - Target options > ABI = o32
 - Target options > Endianness = Big endian
@@ -327,8 +325,6 @@ For targets: `mipsel-unknown-linux-gnu`
 - Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
 - Path and misc options > Use a mirror = ENABLE
 - Path and misc options > Base URL = https://ci-mirrors.rust-lang.org/rustc
-- Path and misc options > Patches origin = Bundled, then local
-- Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = mips
 - Target options > ABI = o32
 - Target options > Endianness = Little endian
@@ -349,8 +345,6 @@ For targets: `mips64-unknown-linux-gnuabi64`
 - Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
 - Path and misc options > Use a mirror = ENABLE
 - Path and misc options > Base URL = https://ci-mirrors.rust-lang.org/rustc
-- Path and misc options > Patches origin = Bundled, then local
-- Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = mips
 - Target options > ABI = n64
 - Target options > Endianness = Big endian
@@ -370,8 +364,6 @@ For targets: `mips64el-unknown-linux-gnuabi64`
 - Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
 - Path and misc options > Use a mirror = ENABLE
 - Path and misc options > Base URL = https://ci-mirrors.rust-lang.org/rustc
-- Path and misc options > Patches origin = Bundled, then local
-- Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = mips
 - Target options > ABI = n64
 - Target options > Endianness = Little endian
diff --git a/src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile
index c08febf423adb..4a090dcdd5085 100644
--- a/src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile
@@ -11,7 +11,6 @@ RUN sh /scripts/rustbuild-setup.sh
 WORKDIR /tmp
 
 COPY scripts/crosstool-ng-build.sh /scripts/
-COPY host-x86_64/dist-mips-linux/patches/ /tmp/patches/
 COPY host-x86_64/dist-mips-linux/mips-linux-gnu.defconfig /tmp/crosstool.defconfig
 RUN /scripts/crosstool-ng-build.sh
 
diff --git a/src/ci/docker/host-x86_64/dist-mips-linux/mips-linux-gnu.defconfig b/src/ci/docker/host-x86_64/dist-mips-linux/mips-linux-gnu.defconfig
index 75743fe81416b..94db07922a226 100644
--- a/src/ci/docker/host-x86_64/dist-mips-linux/mips-linux-gnu.defconfig
+++ b/src/ci/docker/host-x86_64/dist-mips-linux/mips-linux-gnu.defconfig
@@ -2,8 +2,6 @@ CT_CONFIG_VERSION="4"
 CT_PREFIX_DIR="/x-tools/${CT_TARGET}"
 CT_USE_MIRROR=y
 CT_MIRROR_BASE_URL="https://ci-mirrors.rust-lang.org/rustc"
-CT_PATCH_BUNDLED_LOCAL=y
-CT_LOCAL_PATCH_DIR="/tmp/patches"
 CT_ARCH_MIPS=y
 CT_ARCH_mips_o32=y
 CT_ARCH_ARCH="mips32r2"
diff --git a/src/ci/docker/host-x86_64/dist-mips-linux/patches/glibc/2.23/0001-MIPS-SPARC-fix-wrong-vfork-aliases-in-libpthread.so.patch b/src/ci/docker/host-x86_64/dist-mips-linux/patches/glibc/2.23/0001-MIPS-SPARC-fix-wrong-vfork-aliases-in-libpthread.so.patch
deleted file mode 100644
index 393084df3249a..0000000000000
--- a/src/ci/docker/host-x86_64/dist-mips-linux/patches/glibc/2.23/0001-MIPS-SPARC-fix-wrong-vfork-aliases-in-libpthread.so.patch
+++ /dev/null
@@ -1,44 +0,0 @@
-From 43c2948756bb6e144c7b871e827bba37d61ad3a3 Mon Sep 17 00:00:00 2001
-From: Aurelien Jarno <aurelien@aurel32.net>
-Date: Sat, 18 Jun 2016 19:11:23 +0200
-Subject: [PATCH 1/2] MIPS, SPARC: fix wrong vfork aliases in libpthread.so
-
-With recent binutils versions the GNU libc fails to build on at least
-MISP and SPARC, with this kind of error:
-
-  /home/aurel32/glibc/glibc-build/nptl/libpthread.so:(*IND*+0x0): multiple definition of `vfork@GLIBC_2.0'
-  /home/aurel32/glibc/glibc-build/nptl/libpthread.so::(.text+0xee50): first defined here
-
-It appears that on these architectures pt-vfork.S includes vfork.S
-(through the alpha version of pt-vfork.S) and that the __vfork aliases
-are not conditionalized on IS_IN (libc) like on other architectures.
-Therefore the aliases are also wrongly included in libpthread.so.
-
-Fix this by properly conditionalizing the aliases like on other
-architectures.
-
-Changelog:
-	* sysdeps/unix/sysv/linux/mips/vfork.S (__vfork): Conditionalize
-	hidden_def, weak_alias and strong_alias on [IS_IN (libc)].
-	* sysdeps/unix/sysv/linux/sparc/sparc32/vfork.S: Likewise.
-	* sysdeps/unix/sysv/linux/sparc/sparc64/vfork.S: Likewise.
----
- sysdeps/unix/sysv/linux/mips/vfork.S | 2 ++
- 1 file changed, 2 insertions(+)
-
-diff --git a/sysdeps/unix/sysv/linux/mips/vfork.S b/sysdeps/unix/sysv/linux/mips/vfork.S
-index 8c6615143708..c0c0ce699159 100644
---- a/sysdeps/unix/sysv/linux/mips/vfork.S
-+++ b/sysdeps/unix/sysv/linux/mips/vfork.S
-@@ -106,6 +106,8 @@ L(error):
- #endif
- 	END(__vfork)
- 
-+#if IS_IN (libc)
- libc_hidden_def(__vfork)
- weak_alias (__vfork, vfork)
- strong_alias (__vfork, __libc_vfork)
-+#endif
--- 
-2.37.3
-
diff --git a/src/ci/docker/host-x86_64/dist-mips-linux/patches/glibc/2.23/0002-MIPS-SPARC-more-fixes-to-the-vfork-aliases-in-libpth.patch b/src/ci/docker/host-x86_64/dist-mips-linux/patches/glibc/2.23/0002-MIPS-SPARC-more-fixes-to-the-vfork-aliases-in-libpth.patch
deleted file mode 100644
index e28c7ae99f098..0000000000000
--- a/src/ci/docker/host-x86_64/dist-mips-linux/patches/glibc/2.23/0002-MIPS-SPARC-more-fixes-to-the-vfork-aliases-in-libpth.patch
+++ /dev/null
@@ -1,63 +0,0 @@
-From b87c1ec3fa398646f042a68f0ce0f7d09c1348c7 Mon Sep 17 00:00:00 2001
-From: Aurelien Jarno <aurelien@aurel32.net>
-Date: Tue, 21 Jun 2016 23:59:37 +0200
-Subject: [PATCH 2/2] MIPS, SPARC: more fixes to the vfork aliases in
- libpthread.so
-
-Commit 43c29487 tried to fix the vfork aliases in libpthread.so on MIPS
-and SPARC, but failed to do it correctly, introducing an ABI change.
-
-This patch does the remaining changes needed to align the MIPS and SPARC
-vfork implementations with the other architectures. That way the the
-alpha version of pt-vfork.S works correctly for MIPS and SPARC. The
-changes for alpha were done in 82aab97c.
-
-Changelog:
-	* sysdeps/unix/sysv/linux/mips/vfork.S (__vfork): Rename into
-	__libc_vfork.
-	(__vfork) [IS_IN (libc)]: Remove alias.
-	(__libc_vfork) [IS_IN (libc)]: Define as an alias.
-	* sysdeps/unix/sysv/linux/sparc/sparc32/vfork.S: Likewise.
-	* sysdeps/unix/sysv/linux/sparc/sparc64/vfork.S: Likewise.
----
- sysdeps/unix/sysv/linux/mips/vfork.S | 12 ++++++------
- 1 file changed, 6 insertions(+), 6 deletions(-)
-
-diff --git a/sysdeps/unix/sysv/linux/mips/vfork.S b/sysdeps/unix/sysv/linux/mips/vfork.S
-index c0c0ce699159..1867c8626ebe 100644
---- a/sysdeps/unix/sysv/linux/mips/vfork.S
-+++ b/sysdeps/unix/sysv/linux/mips/vfork.S
-@@ -31,13 +31,13 @@
- LOCALSZ= 1
- FRAMESZ= (((NARGSAVE+LOCALSZ)*SZREG)+ALSZ)&ALMASK
- GPOFF= FRAMESZ-(1*SZREG)
--NESTED(__vfork,FRAMESZ,sp)
-+NESTED(__libc_vfork,FRAMESZ,sp)
- #ifdef __PIC__
- 	SETUP_GP
- #endif
- 	PTR_SUBU sp, FRAMESZ
- 	cfi_adjust_cfa_offset (FRAMESZ)
--	SETUP_GP64_REG (a5, __vfork)
-+	SETUP_GP64_REG (a5, __libc_vfork)
- #ifdef __PIC__
- 	SAVE_GP (GPOFF)
- #endif
-@@ -104,10 +104,10 @@ L(error):
- 	RESTORE_GP64_REG
- 	j		__syscall_error
- #endif
--	END(__vfork)
-+	END(__libc_vfork)
- 
- #if IS_IN (libc)
--libc_hidden_def(__vfork)
--weak_alias (__vfork, vfork)
--strong_alias (__vfork, __libc_vfork)
-+weak_alias (__libc_vfork, vfork)
-+strong_alias (__libc_vfork, __vfork)
-+libc_hidden_def (__vfork)
- #endif
--- 
-2.37.3
-
diff --git a/src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile
index 10f31075e2d55..18b0375f40080 100644
--- a/src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile
@@ -11,7 +11,6 @@ RUN sh /scripts/rustbuild-setup.sh
 WORKDIR /tmp
 
 COPY scripts/crosstool-ng-build.sh /scripts/
-COPY host-x86_64/dist-mips-linux/patches/ /tmp/patches/
 COPY host-x86_64/dist-mips64-linux/mips64-linux-gnu.defconfig /tmp/crosstool.defconfig
 RUN /scripts/crosstool-ng-build.sh
 
diff --git a/src/ci/docker/host-x86_64/dist-mips64-linux/mips64-linux-gnu.defconfig b/src/ci/docker/host-x86_64/dist-mips64-linux/mips64-linux-gnu.defconfig
index 4b8f7a5492033..f295a2fafc6b1 100644
--- a/src/ci/docker/host-x86_64/dist-mips64-linux/mips64-linux-gnu.defconfig
+++ b/src/ci/docker/host-x86_64/dist-mips64-linux/mips64-linux-gnu.defconfig
@@ -2,8 +2,6 @@ CT_CONFIG_VERSION="4"
 CT_PREFIX_DIR="/x-tools/${CT_TARGET}"
 CT_USE_MIRROR=y
 CT_MIRROR_BASE_URL="https://ci-mirrors.rust-lang.org/rustc"
-CT_PATCH_BUNDLED_LOCAL=y
-CT_LOCAL_PATCH_DIR="/tmp/patches"
 CT_ARCH_MIPS=y
 CT_ARCH_mips_n64=y
 CT_ARCH_64=y
diff --git a/src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile
index 5ab4a53de8a88..87407203880b4 100644
--- a/src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile
@@ -11,7 +11,6 @@ RUN sh /scripts/rustbuild-setup.sh
 WORKDIR /tmp
 
 COPY scripts/crosstool-ng-build.sh /scripts/
-COPY host-x86_64/dist-mips-linux/patches/ /tmp/patches/
 COPY host-x86_64/dist-mips64el-linux/mips64el-linux-gnu.defconfig /tmp/crosstool.defconfig
 RUN /scripts/crosstool-ng-build.sh
 
diff --git a/src/ci/docker/host-x86_64/dist-mips64el-linux/mips64el-linux-gnu.defconfig b/src/ci/docker/host-x86_64/dist-mips64el-linux/mips64el-linux-gnu.defconfig
index 9c8eb5007b79b..47d6246356526 100644
--- a/src/ci/docker/host-x86_64/dist-mips64el-linux/mips64el-linux-gnu.defconfig
+++ b/src/ci/docker/host-x86_64/dist-mips64el-linux/mips64el-linux-gnu.defconfig
@@ -2,8 +2,6 @@ CT_CONFIG_VERSION="4"
 CT_PREFIX_DIR="/x-tools/${CT_TARGET}"
 CT_USE_MIRROR=y
 CT_MIRROR_BASE_URL="https://ci-mirrors.rust-lang.org/rustc"
-CT_PATCH_BUNDLED_LOCAL=y
-CT_LOCAL_PATCH_DIR="/tmp/patches"
 CT_ARCH_MIPS=y
 CT_ARCH_mips_n64=y
 CT_ARCH_LE=y
diff --git a/src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile
index 0bbaf00339d0a..553f6ea86b72d 100644
--- a/src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile
@@ -11,7 +11,6 @@ RUN sh /scripts/rustbuild-setup.sh
 WORKDIR /tmp
 
 COPY scripts/crosstool-ng-build.sh /scripts/
-COPY host-x86_64/dist-mips-linux/patches/ /tmp/patches/
 COPY host-x86_64/dist-mipsel-linux/mipsel-linux-gnu.defconfig /tmp/crosstool.defconfig
 RUN /scripts/crosstool-ng-build.sh
 
diff --git a/src/ci/docker/host-x86_64/dist-mipsel-linux/mipsel-linux-gnu.defconfig b/src/ci/docker/host-x86_64/dist-mipsel-linux/mipsel-linux-gnu.defconfig
index a9dae121e536a..5daa83ebc02a7 100644
--- a/src/ci/docker/host-x86_64/dist-mipsel-linux/mipsel-linux-gnu.defconfig
+++ b/src/ci/docker/host-x86_64/dist-mipsel-linux/mipsel-linux-gnu.defconfig
@@ -2,8 +2,6 @@ CT_CONFIG_VERSION="4"
 CT_PREFIX_DIR="/x-tools/${CT_TARGET}"
 CT_USE_MIRROR=y
 CT_MIRROR_BASE_URL="https://ci-mirrors.rust-lang.org/rustc"
-CT_PATCH_BUNDLED_LOCAL=y
-CT_LOCAL_PATCH_DIR="/tmp/patches"
 CT_ARCH_MIPS=y
 CT_ARCH_mips_o32=y
 CT_ARCH_LE=y
diff --git a/src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile b/src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile
index f52e306974cce..9ca8cc740a5c7 100644
--- a/src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile
+++ b/src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile
@@ -1,4 +1,6 @@
-FROM ubuntu:22.04
+# We use the ghcr base image because ghcr doesn't have a rate limit
+# and the mingw-check-tidy job doesn't cache docker images in CI.
+FROM ghcr.io/rust-lang/ubuntu:22.04
 
 ARG DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
diff --git a/src/ci/github-actions/jobs.yml b/src/ci/github-actions/jobs.yml
index 1ab70e4e0aaba..799ea3e9ad2df 100644
--- a/src/ci/github-actions/jobs.yml
+++ b/src/ci/github-actions/jobs.yml
@@ -448,11 +448,18 @@ auto:
       SCRIPT: make ci-msvc
     <<: *job-windows-8c
 
-  - name: i686-msvc
+  # i686-msvc is split into two jobs to run tests in parallel.
+  - name: i686-msvc-1
     env:
       RUST_CONFIGURE_ARGS: --build=i686-pc-windows-msvc
-      SCRIPT: make ci-msvc
-    <<: *job-windows-8c
+      SCRIPT: make ci-msvc-py-set1
+    <<: *job-windows
+
+  - name: i686-msvc-2
+    env:
+      RUST_CONFIGURE_ARGS: --build=i686-pc-windows-msvc
+      SCRIPT: make ci-msvc-ps1-set2
+    <<: *job-windows
 
   # x86_64-msvc-ext is split into multiple jobs to run tests in parallel.
   - name: x86_64-msvc-ext1
diff --git a/tests/ui/resolve/resolve-issue-135614-assoc-const.import_trait_associated_functions.stderr b/tests/ui/resolve/resolve-issue-135614-assoc-const.import_trait_associated_functions.stderr
new file mode 100644
index 0000000000000..b41fa1818e25a
--- /dev/null
+++ b/tests/ui/resolve/resolve-issue-135614-assoc-const.import_trait_associated_functions.stderr
@@ -0,0 +1,19 @@
+error[E0005]: refutable pattern in local binding
+  --> $DIR/resolve-issue-135614-assoc-const.rs:21:9
+   |
+LL |     let DEFAULT: u32 = 0;
+   |         ^^^^^^^ pattern `1_u32..=u32::MAX` not covered
+LL |     const DEFAULT: u32 = 0;
+   |     ------------------ missing patterns are not covered because `DEFAULT` is interpreted as a constant pattern, not a new variable
+   |
+   = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
+   = note: for more information, visit https://doc.rust-lang.org/book/ch19-02-refutability.html
+   = note: the matched value is of type `u32`
+help: introduce a variable instead
+   |
+LL |     let DEFAULT_var: u32 = 0;
+   |         ~~~~~~~~~~~
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0005`.
diff --git a/tests/ui/resolve/resolve-issue-135614-assoc-const.normal.stderr b/tests/ui/resolve/resolve-issue-135614-assoc-const.normal.stderr
new file mode 100644
index 0000000000000..908f5bdd89749
--- /dev/null
+++ b/tests/ui/resolve/resolve-issue-135614-assoc-const.normal.stderr
@@ -0,0 +1,30 @@
+error[E0658]: `use` associated items of traits is unstable
+  --> $DIR/resolve-issue-135614-assoc-const.rs:6:5
+   |
+LL | use MyDefault::DEFAULT;
+   |     ^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #134691 <https://github.com/rust-lang/rust/issues/134691> for more information
+   = help: add `#![feature(import_trait_associated_functions)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0005]: refutable pattern in local binding
+  --> $DIR/resolve-issue-135614-assoc-const.rs:21:9
+   |
+LL |     let DEFAULT: u32 = 0;
+   |         ^^^^^^^ pattern `1_u32..=u32::MAX` not covered
+LL |     const DEFAULT: u32 = 0;
+   |     ------------------ missing patterns are not covered because `DEFAULT` is interpreted as a constant pattern, not a new variable
+   |
+   = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
+   = note: for more information, visit https://doc.rust-lang.org/book/ch19-02-refutability.html
+   = note: the matched value is of type `u32`
+help: introduce a variable instead
+   |
+LL |     let DEFAULT_var: u32 = 0;
+   |         ~~~~~~~~~~~
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0005, E0658.
+For more information about an error, try `rustc --explain E0005`.
diff --git a/tests/ui/resolve/resolve-issue-135614-assoc-const.rs b/tests/ui/resolve/resolve-issue-135614-assoc-const.rs
new file mode 100644
index 0000000000000..5a592922cd461
--- /dev/null
+++ b/tests/ui/resolve/resolve-issue-135614-assoc-const.rs
@@ -0,0 +1,30 @@
+//@ revisions: normal import_trait_associated_functions
+#![cfg_attr(import_trait_associated_functions, feature(import_trait_associated_functions))]
+
+// Makes sure that imported constant can be used in pattern bindings.
+
+use MyDefault::DEFAULT; //[normal]~ ERROR `use` associated items of traits is unstable
+
+trait MyDefault {
+    const DEFAULT: Self;
+}
+
+impl MyDefault for u32 {
+    const DEFAULT: u32 = 0;
+}
+
+impl MyDefault for () {
+    const DEFAULT: () = ();
+}
+
+fn foo(x: u32) -> u32 {
+    let DEFAULT: u32 = 0; //~ ERROR refutable pattern in local binding
+    const DEFAULT: u32 = 0;
+    if let DEFAULT = x { DEFAULT } else { 1 }
+}
+
+fn bar() {
+    let DEFAULT = ();
+}
+
+fn main() {}
diff --git a/tests/ui/resolve/resolve-issue-135614.normal.stderr b/tests/ui/resolve/resolve-issue-135614.normal.stderr
new file mode 100644
index 0000000000000..a9adeb0848e6f
--- /dev/null
+++ b/tests/ui/resolve/resolve-issue-135614.normal.stderr
@@ -0,0 +1,13 @@
+error[E0658]: `use` associated items of traits is unstable
+  --> $DIR/resolve-issue-135614.rs:7:5
+   |
+LL | use A::b;
+   |     ^^^^
+   |
+   = note: see issue #134691 <https://github.com/rust-lang/rust/issues/134691> for more information
+   = help: add `#![feature(import_trait_associated_functions)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/resolve/resolve-issue-135614.rs b/tests/ui/resolve/resolve-issue-135614.rs
new file mode 100644
index 0000000000000..fec9499365bcb
--- /dev/null
+++ b/tests/ui/resolve/resolve-issue-135614.rs
@@ -0,0 +1,15 @@
+//@ revisions: normal import_trait_associated_functions
+//@[import_trait_associated_functions] check-pass
+#![cfg_attr(import_trait_associated_functions, feature(import_trait_associated_functions))]
+
+// Makes sure that imported associated functions are shadowed by the local declarations.
+
+use A::b; //[normal]~ ERROR `use` associated items of traits is unstable
+
+trait A {
+    fn b() {}
+}
+
+fn main() {
+    let b: ();
+}