Auto merge of #152484 - matthiaskrgr:rollup-h4u26eb, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - rust-lang/rust#152419 (Move more query system code)
 - rust-lang/rust#152431 (Restrict the set of things that const stability can be applied to)
 - rust-lang/rust#152436 (Reenable a GCI+mGCA+GCPT test case)
 - rust-lang/rust#152021 (Bump tvOS, visionOS and watchOS Aarch64 targets to tier 2)
 - rust-lang/rust#152146 (mGCA: Add associated const type check)
 - rust-lang/rust#152372 (style: remove unneeded trailing commas)
 - rust-lang/rust#152383 (BikeshedGuaranteedNoDrop trait: add comments indicating that it can be observed on stable)
 - rust-lang/rust#152397 (Update books)
 - rust-lang/rust#152441 (Fix typos and grammar in top-level and src/doc documentation)

CONTRIBUTING.md

@@ -10,7 +10,7 @@ the Zulip stream is the best place to *ask* for help.
 
 Documentation for contributing to the compiler or tooling is located in the [Guide to Rustc
 Development][rustc-dev-guide], commonly known as the [rustc-dev-guide]. Documentation for the
-standard library in the [Standard library developers Guide][std-dev-guide], commonly known as the [std-dev-guide].
+standard library is in the [Standard library developers Guide][std-dev-guide], commonly known as the [std-dev-guide].
 
 ## Making changes to subtrees and submodules
 

Cargo.lock

@@ -4492,6 +4492,7 @@ name = "rustc_query_impl"
 version = "0.0.0"
 dependencies = [
  "measureme",
+ "rustc_abi",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hashes",
@@ -4501,7 +4502,9 @@ dependencies = [
  "rustc_middle",
  "rustc_query_system",
  "rustc_serialize",
+ "rustc_session",
  "rustc_span",
+ "rustc_thread_pool",
  "tracing",
 ]
 

INSTALL.md

@@ -233,7 +233,7 @@ itself back on after some time).
 
 ### MSVC
 
-MSVC builds of Rust additionally requires an installation of:
+MSVC builds of Rust additionally require an installation of:
 
 - Visual Studio 2022 (or later) build tools so `rustc` can use its linker. Older
   Visual Studio versions such as 2019 *may* work but aren't actively tested.

RELEASES.md

@@ -1546,7 +1546,7 @@ Compatibility Notes
 - [Check well-formedness of the source type's signature in fn pointer casts.](https://github.com/rust-lang/rust/pull/129021) This partly closes a soundness hole that comes when casting a function item to function pointer
 - [Use equality instead of subtyping when resolving type dependent paths.](https://github.com/rust-lang/rust/pull/129073)
 - Linking on macOS now correctly includes Rust's default deployment target. Due to a linker bug, you might have to pass `MACOSX_DEPLOYMENT_TARGET` or fix your `#[link]` attributes to point to the correct frameworks. See <https://github.com/rust-lang/rust/pull/129369>.
-- [Rust will now correctly raise an error for `repr(Rust)` written on non-`struct`/`enum`/`union` items, since it previous did not have any effect.](https://github.com/rust-lang/rust/pull/129422)
+- [Rust will now correctly raise an error for `repr(Rust)` written on non-`struct`/`enum`/`union` items, since it previously did not have any effect.](https://github.com/rust-lang/rust/pull/129422)
 - The future incompatibility lint `deprecated_cfg_attr_crate_type_name` [has been made into a hard error](https://github.com/rust-lang/rust/pull/129670). It was used to deny usage of `#![crate_type]` and `#![crate_name]` attributes in `#![cfg_attr]`, which required a hack in the compiler to be able to change the used crate type and crate name after cfg expansion.
   Users can use `--crate-type` instead of `#![cfg_attr(..., crate_type = "...")]` and `--crate-name` instead of `#![cfg_attr(..., crate_name = "...")]` when running `rustc`/`cargo rustc` on the command line.
   Use of those two attributes outside of `#![cfg_attr]` continue to be fully supported.
@@ -1722,7 +1722,7 @@ Cargo
 Compatibility Notes
 -------------------
  - We now [disallow setting some built-in cfgs via the command-line](https://github.com/rust-lang/rust/pull/126158) with the newly added [`explicit_builtin_cfgs_in_flags`](https://doc.rust-lang.org/rustc/lints/listing/deny-by-default.html#explicit-builtin-cfgs-in-flags) lint in order to prevent incoherent state, eg. `windows` cfg active but target is Linux based. The appropriate [`rustc` flag](https://doc.rust-lang.org/rustc/command-line-arguments.html) should be used instead.
-- The standard library has a new implementation of `binary_search` which is significantly improves performance ([#128254](https://github.com/rust-lang/rust/pull/128254)). However when a sorted slice has multiple values which compare equal, the new implementation may select a different value among the equal ones than the old implementation.
+- The standard library has a new implementation of `binary_search` which significantly improves performance ([#128254](https://github.com/rust-lang/rust/pull/128254)). However when a sorted slice has multiple values which compare equal, the new implementation may select a different value among the equal ones than the old implementation.
 - [illumos/Solaris now sets `MSG_NOSIGNAL` when writing to sockets](https://github.com/rust-lang/rust/pull/128259). This avoids killing the process with SIGPIPE when writing to a closed socket, which matches the existing behavior on other UNIX targets.
 - [Removes a problematic hack that always passed the --whole-archive linker flag for tests, which may cause linker errors for code accidentally relying on it.](https://github.com/rust-lang/rust/pull/128400)
 - The WebAssembly target features `multivalue` and `reference-types` are now
@@ -1872,7 +1872,7 @@ These changes do not affect any public interfaces of Rust, but they represent
 significant improvements to the performance or internals of rustc and related
 tools.
 
-- [Add a Rust-for Linux `auto` CI job to check kernel builds.](https://github.com/rust-lang/rust/pull/125209/)
+- [Add a Rust-for-Linux `auto` CI job to check kernel builds.](https://github.com/rust-lang/rust/pull/125209/)
 
 Version 1.80.1 (2024-08-08)
 ===========================
@@ -4510,7 +4510,7 @@ Compatibility Notes
   saturating to `0` instead][89926]. In the real world the panic happened mostly
   on platforms with buggy monotonic clock implementations rather than catching
   programming errors like reversing the start and end times. Such programming
-  errors will now results in `0` rather than a panic.
+  errors will now result in `0` rather than a panic.
 - In a future release we're planning to increase the baseline requirements for
   the Linux kernel to version 3.2, and for glibc to version 2.17. We'd love
   your feedback in [PR #95026][95026].

compiler/rustc_attr_parsing/src/attributes/stability.rs

@@ -244,7 +244,20 @@ impl<S: Stage> AttributeParser<S> for ConstStabilityParser {
             this.promotable = true;
         }),
     ];
-    const ALLOWED_TARGETS: AllowedTargets = ALLOWED_TARGETS;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
+        Allow(Target::Fn),
+        Allow(Target::Method(MethodKind::Inherent)),
+        Allow(Target::Method(MethodKind::TraitImpl)),
+        Allow(Target::Method(MethodKind::Trait { body: true })),
+        Allow(Target::Impl { of_trait: false }),
+        Allow(Target::Impl { of_trait: true }),
+        Allow(Target::Use), // FIXME I don't think this does anything?
+        Allow(Target::Const),
+        Allow(Target::AssocConst),
+        Allow(Target::Trait),
+        Allow(Target::Static),
+        Allow(Target::Crate),
+    ]);
 
     fn finalize(mut self, cx: &FinalizeContext<'_, '_, S>) -> Option<AttributeKind> {
         if self.promotable {

compiler/rustc_expand/src/base.rs

@@ -962,15 +962,6 @@ impl SyntaxExtension {
 
         let stability = find_attr!(attrs, AttributeKind::Stability { stability, .. } => *stability);
 
-        // FIXME(jdonszelmann): make it impossible to miss the or_else in the typesystem
-        if let Some(sp) =
-            find_attr!(attrs, AttributeKind::RustcConstStability { span, .. } => *span)
-        {
-            sess.dcx().emit_err(errors::MacroConstStability {
-                span: sp,
-                head_span: sess.source_map().guess_head_span(span),
-            });
-        }
         if let Some(sp) = find_attr!(attrs, AttributeKind::RustcBodyStability{ span, .. } => *span)
         {
             sess.dcx().emit_err(errors::MacroBodyStability {

compiler/rustc_expand/src/errors.rs

@@ -80,16 +80,6 @@ pub(crate) struct ResolveRelativePath {
     pub path: String,
 }
 
-#[derive(Diagnostic)]
-#[diag("macros cannot have const stability attributes")]
-pub(crate) struct MacroConstStability {
-    #[primary_span]
-    #[label("invalid const stability attribute")]
-    pub span: Span,
-    #[label("const stability attribute affects this macro")]
-    pub head_span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag("macros cannot have body stability attributes")]
 pub(crate) struct MacroBodyStability {

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1569,11 +1569,40 @@ pub(super) fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, def_id:
 
     let predicates = predicates.instantiate_identity(tcx);
 
+    let assoc_const_obligations: Vec<_> = predicates
+        .predicates
+        .iter()
+        .copied()
+        .zip(predicates.spans.iter().copied())
+        .filter_map(|(clause, sp)| {
+            let proj = clause.as_projection_clause()?;
+            let pred_binder = proj
+                .map_bound(|pred| {
+                    pred.term.as_const().map(|ct| {
+                        let assoc_const_ty = tcx
+                            .type_of(pred.projection_term.def_id)
+                            .instantiate(tcx, pred.projection_term.args);
+                        ty::ClauseKind::ConstArgHasType(ct, assoc_const_ty)
+                    })
+                })
+                .transpose();
+            pred_binder.map(|pred_binder| {
+                let cause = traits::ObligationCause::new(
+                    sp,
+                    wfcx.body_def_id,
+                    ObligationCauseCode::WhereClause(def_id.to_def_id(), sp),
+                );
+                Obligation::new(tcx, cause, wfcx.param_env, pred_binder)
+            })
+        })
+        .collect();
+
     assert_eq!(predicates.predicates.len(), predicates.spans.len());
     let wf_obligations = predicates.into_iter().flat_map(|(p, sp)| {
         traits::wf::clause_obligations(infcx, wfcx.param_env, wfcx.body_def_id, p, sp)
     });
-    let obligations: Vec<_> = wf_obligations.chain(default_obligations).collect();
+    let obligations: Vec<_> =
+        wf_obligations.chain(default_obligations).chain(assoc_const_obligations).collect();
     wfcx.register_obligations(obligations);
 }
 

compiler/rustc_interface/src/interface.rs

@@ -16,8 +16,7 @@ use rustc_parse::lexer::StripTokens;
 use rustc_parse::new_parser_from_source_str;
 use rustc_parse::parser::Recovery;
 use rustc_parse::parser::attr::AllowLeadingUnsafe;
-use rustc_query_impl::QueryCtxt;
-use rustc_query_system::query::print_query_stack;
+use rustc_query_impl::{QueryCtxt, print_query_stack};
 use rustc_session::config::{self, Cfg, CheckCfg, ExpectedValues, Input, OutFileName};
 use rustc_session::parse::ParseSess;
 use rustc_session::{CompilerIO, EarlyDiagCtxt, Session, lint};

compiler/rustc_interface/src/util.rs

@@ -184,8 +184,7 @@ pub(crate) fn run_in_thread_pool_with_globals<
     use rustc_data_structures::defer;
     use rustc_data_structures::sync::FromDyn;
     use rustc_middle::ty::tls;
-    use rustc_query_impl::QueryCtxt;
-    use rustc_query_system::query::{QueryContext, break_query_cycles};
+    use rustc_query_impl::{QueryCtxt, break_query_cycles};
 
     let thread_stack_size = init_stack_size(thread_builder_diag);
 

compiler/rustc_middle/src/query/mod.rs

@@ -13,7 +13,6 @@ mod keys;
 pub mod on_disk_cache;
 #[macro_use]
 pub mod plumbing;
-pub mod values;
 
 pub fn describe_as_module(def_id: impl Into<LocalDefId>, tcx: TyCtxt<'_>) -> String {
     let def_id = def_id.into();

compiler/rustc_next_trait_solver/src/solve/trait_goals.rs

@@ -687,6 +687,9 @@ where
     ///
     /// because these impls overlap, and I'd rather not build a coherence hack for
     /// this harmless overlap.
+    ///
+    /// This trait is indirectly exposed on stable, so do *not* extend the set of types that
+    /// implement the trait without FCP!
     fn consider_builtin_bikeshed_guaranteed_no_drop_candidate(
         ecx: &mut EvalCtxt<'_, D>,
         goal: Goal<I, Self>,

compiler/rustc_query_impl/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2024"
 [dependencies]
 # tidy-alphabetical-start
 measureme = "12.0.1"
+rustc_abi = { path = "../rustc_abi" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_hashes = { path = "../rustc_hashes" }
@@ -15,6 +16,8 @@ rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_query_system = { path = "../rustc_query_system" }
 rustc_serialize = { path = "../rustc_serialize" }
+rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
+rustc_thread_pool = { path = "../rustc_thread_pool" }
 tracing = "0.1"
 # tidy-alphabetical-end

compiler/rustc_query_impl/src/error.rs

@@ -1,3 +1,4 @@
+use rustc_errors::codes::*;
 use rustc_hir::limit::Limit;
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
@@ -22,3 +23,59 @@ pub(crate) struct QueryOverflowNote {
     pub desc: String,
     pub depth: usize,
 }
+
+#[derive(Subdiagnostic)]
+#[note("...which requires {$desc}...")]
+pub(crate) struct CycleStack {
+    #[primary_span]
+    pub span: Span,
+    pub desc: String,
+}
+
+#[derive(Subdiagnostic)]
+pub(crate) enum StackCount {
+    #[note("...which immediately requires {$stack_bottom} again")]
+    Single,
+    #[note("...which again requires {$stack_bottom}, completing the cycle")]
+    Multiple,
+}
+
+#[derive(Subdiagnostic)]
+pub(crate) enum Alias {
+    #[note("type aliases cannot be recursive")]
+    #[help("consider using a struct, enum, or union instead to break the cycle")]
+    #[help(
+        "see <https://doc.rust-lang.org/reference/types.html#recursive-types> for more information"
+    )]
+    Ty,
+    #[note("trait aliases cannot be recursive")]
+    Trait,
+}
+
+#[derive(Subdiagnostic)]
+#[note("cycle used when {$usage}")]
+pub(crate) struct CycleUsage {
+    #[primary_span]
+    pub span: Span,
+    pub usage: String,
+}
+
+#[derive(Diagnostic)]
+#[diag("cycle detected when {$stack_bottom}", code = E0391)]
+pub(crate) struct Cycle {
+    #[primary_span]
+    pub span: Span,
+    pub stack_bottom: String,
+    #[subdiagnostic]
+    pub cycle_stack: Vec<CycleStack>,
+    #[subdiagnostic]
+    pub stack_count: StackCount,
+    #[subdiagnostic]
+    pub alias: Option<Alias>,
+    #[subdiagnostic]
+    pub cycle_usage: Option<CycleUsage>,
+    #[note(
+        "see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information"
+    )]
+    pub note_span: (),
+}

compiler/rustc_query_impl/src/execution.rs

@@ -9,13 +9,13 @@ use rustc_middle::dep_graph::DepsType;
 use rustc_middle::ty::TyCtxt;
 use rustc_query_system::dep_graph::{DepGraphData, DepNodeKey, HasDepContext};
 use rustc_query_system::query::{
-    ActiveKeyStatus, CycleError, CycleErrorHandling, QueryCache, QueryContext, QueryJob,
-    QueryJobId, QueryJobInfo, QueryLatch, QueryMap, QueryMode, QueryStackDeferred, QueryStackFrame,
-    QueryState, incremental_verify_ich, report_cycle,
+    ActiveKeyStatus, CycleError, CycleErrorHandling, QueryCache, QueryJob, QueryJobId, QueryLatch,
+    QueryMode, QueryStackDeferred, QueryStackFrame, QueryState, incremental_verify_ich,
 };
 use rustc_span::{DUMMY_SP, Span};
 
 use crate::dep_graph::{DepContext, DepNode, DepNodeIndex};
+use crate::job::{QueryJobInfo, QueryMap, find_cycle_in_stack, report_cycle};
 use crate::{QueryCtxt, QueryFlags, SemiDynamicQueryDispatcher};
 
 #[inline]
@@ -218,7 +218,7 @@ fn cycle_error<'tcx, C: QueryCache, const FLAGS: QueryFlags>(
         .ok()
         .expect("failed to collect active queries");
 
-    let error = try_execute.find_cycle_in_stack(query_map, &qcx.current_query_job(), span);
+    let error = find_cycle_in_stack(try_execute, query_map, &qcx.current_query_job(), span);
     (mk_cycle(query, qcx, error.lift()), None)
 }
 

compiler/rustc_query_impl/src/job.rs

@@ -0,0 +1,500 @@
+use std::io::Write;
+use std::iter;
+use std::sync::Arc;
+
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_errors::{Diag, DiagCtxtHandle};
+use rustc_hir::def::DefKind;
+use rustc_query_system::query::{
+    CycleError, QueryInfo, QueryJob, QueryJobId, QueryLatch, QueryStackDeferred, QueryStackFrame,
+    QueryWaiter,
+};
+use rustc_session::Session;
+use rustc_span::{DUMMY_SP, Span};
+
+use crate::QueryCtxt;
+use crate::dep_graph::DepContext;
+
+/// Map from query job IDs to job information collected by
+/// `collect_active_jobs_from_all_queries`.
+pub type QueryMap<'tcx> = FxHashMap<QueryJobId, QueryJobInfo<'tcx>>;
+
+fn query_job_id_frame<'a, 'tcx>(
+    id: QueryJobId,
+    map: &'a QueryMap<'tcx>,
+) -> QueryStackFrame<QueryStackDeferred<'tcx>> {
+    map.get(&id).unwrap().frame.clone()
+}
+
+fn query_job_id_span<'a, 'tcx>(id: QueryJobId, map: &'a QueryMap<'tcx>) -> Span {
+    map.get(&id).unwrap().job.span
+}
+
+fn query_job_id_parent<'a, 'tcx>(id: QueryJobId, map: &'a QueryMap<'tcx>) -> Option<QueryJobId> {
+    map.get(&id).unwrap().job.parent
+}
+
+fn query_job_id_latch<'a, 'tcx>(
+    id: QueryJobId,
+    map: &'a QueryMap<'tcx>,
+) -> Option<&'a QueryLatch<'tcx>> {
+    map.get(&id).unwrap().job.latch.as_ref()
+}
+
+#[derive(Clone, Debug)]
+pub struct QueryJobInfo<'tcx> {
+    pub frame: QueryStackFrame<QueryStackDeferred<'tcx>>,
+    pub job: QueryJob<'tcx>,
+}
+
+pub(crate) fn find_cycle_in_stack<'tcx>(
+    id: QueryJobId,
+    query_map: QueryMap<'tcx>,
+    current_job: &Option<QueryJobId>,
+    span: Span,
+) -> CycleError<QueryStackDeferred<'tcx>> {
+    // Find the waitee amongst `current_job` parents
+    let mut cycle = Vec::new();
+    let mut current_job = Option::clone(current_job);
+
+    while let Some(job) = current_job {
+        let info = query_map.get(&job).unwrap();
+        cycle.push(QueryInfo { span: info.job.span, frame: info.frame.clone() });
+
+        if job == id {
+            cycle.reverse();
+
+            // This is the end of the cycle
+            // The span entry we included was for the usage
+            // of the cycle itself, and not part of the cycle
+            // Replace it with the span which caused the cycle to form
+            cycle[0].span = span;
+            // Find out why the cycle itself was used
+            let usage = info
+                .job
+                .parent
+                .as_ref()
+                .map(|parent| (info.job.span, query_job_id_frame(*parent, &query_map)));
+            return CycleError { usage, cycle };
+        }
+
+        current_job = info.job.parent;
+    }
+
+    panic!("did not find a cycle")
+}
+
+#[cold]
+#[inline(never)]
+pub(crate) fn find_dep_kind_root<'tcx>(
+    id: QueryJobId,
+    query_map: QueryMap<'tcx>,
+) -> (QueryJobInfo<'tcx>, usize) {
+    let mut depth = 1;
+    let info = query_map.get(&id).unwrap();
+    let dep_kind = info.frame.dep_kind;
+    let mut current_id = info.job.parent;
+    let mut last_layout = (info.clone(), depth);
+
+    while let Some(id) = current_id {
+        let info = query_map.get(&id).unwrap();
+        if info.frame.dep_kind == dep_kind {
+            depth += 1;
+            last_layout = (info.clone(), depth);
+        }
+        current_id = info.job.parent;
+    }
+    last_layout
+}
+
+/// A resumable waiter of a query. The usize is the index into waiters in the query's latch
+type Waiter = (QueryJobId, usize);
+
+/// Visits all the non-resumable and resumable waiters of a query.
+/// Only waiters in a query are visited.
+/// `visit` is called for every waiter and is passed a query waiting on `query_ref`
+/// and a span indicating the reason the query waited on `query_ref`.
+/// If `visit` returns Some, this function returns.
+/// For visits of non-resumable waiters it returns the return value of `visit`.
+/// For visits of resumable waiters it returns Some(Some(Waiter)) which has the
+/// required information to resume the waiter.
+/// If all `visit` calls returns None, this function also returns None.
+fn visit_waiters<'tcx, F>(
+    query_map: &QueryMap<'tcx>,
+    query: QueryJobId,
+    mut visit: F,
+) -> Option<Option<Waiter>>
+where
+    F: FnMut(Span, QueryJobId) -> Option<Option<Waiter>>,
+{
+    // Visit the parent query which is a non-resumable waiter since it's on the same stack
+    if let Some(parent) = query_job_id_parent(query, query_map)
+        && let Some(cycle) = visit(query_job_id_span(query, query_map), parent)
+    {
+        return Some(cycle);
+    }
+
+    // Visit the explicit waiters which use condvars and are resumable
+    if let Some(latch) = query_job_id_latch(query, query_map) {
+        for (i, waiter) in latch.info.lock().waiters.iter().enumerate() {
+            if let Some(waiter_query) = waiter.query {
+                if visit(waiter.span, waiter_query).is_some() {
+                    // Return a value which indicates that this waiter can be resumed
+                    return Some(Some((query, i)));
+                }
+            }
+        }
+    }
+
+    None
+}
+
+/// Look for query cycles by doing a depth first search starting at `query`.
+/// `span` is the reason for the `query` to execute. This is initially DUMMY_SP.
+/// If a cycle is detected, this initial value is replaced with the span causing
+/// the cycle.
+fn cycle_check<'tcx>(
+    query_map: &QueryMap<'tcx>,
+    query: QueryJobId,
+    span: Span,
+    stack: &mut Vec<(Span, QueryJobId)>,
+    visited: &mut FxHashSet<QueryJobId>,
+) -> Option<Option<Waiter>> {
+    if !visited.insert(query) {
+        return if let Some(p) = stack.iter().position(|q| q.1 == query) {
+            // We detected a query cycle, fix up the initial span and return Some
+
+            // Remove previous stack entries
+            stack.drain(0..p);
+            // Replace the span for the first query with the cycle cause
+            stack[0].0 = span;
+            Some(None)
+        } else {
+            None
+        };
+    }
+
+    // Query marked as visited is added it to the stack
+    stack.push((span, query));
+
+    // Visit all the waiters
+    let r = visit_waiters(query_map, query, |span, successor| {
+        cycle_check(query_map, successor, span, stack, visited)
+    });
+
+    // Remove the entry in our stack if we didn't find a cycle
+    if r.is_none() {
+        stack.pop();
+    }
+
+    r
+}
+
+/// Finds out if there's a path to the compiler root (aka. code which isn't in a query)
+/// from `query` without going through any of the queries in `visited`.
+/// This is achieved with a depth first search.
+fn connected_to_root<'tcx>(
+    query_map: &QueryMap<'tcx>,
+    query: QueryJobId,
+    visited: &mut FxHashSet<QueryJobId>,
+) -> bool {
+    // We already visited this or we're deliberately ignoring it
+    if !visited.insert(query) {
+        return false;
+    }
+
+    // This query is connected to the root (it has no query parent), return true
+    if query_job_id_parent(query, query_map).is_none() {
+        return true;
+    }
+
+    visit_waiters(query_map, query, |_, successor| {
+        connected_to_root(query_map, successor, visited).then_some(None)
+    })
+    .is_some()
+}
+
+// Deterministically pick an query from a list
+fn pick_query<'a, 'tcx, T, F>(query_map: &QueryMap<'tcx>, queries: &'a [T], f: F) -> &'a T
+where
+    F: Fn(&T) -> (Span, QueryJobId),
+{
+    // Deterministically pick an entry point
+    // FIXME: Sort this instead
+    queries
+        .iter()
+        .min_by_key(|v| {
+            let (span, query) = f(v);
+            let hash = query_job_id_frame(query, query_map).hash;
+            // Prefer entry points which have valid spans for nicer error messages
+            // We add an integer to the tuple ensuring that entry points
+            // with valid spans are picked first
+            let span_cmp = if span == DUMMY_SP { 1 } else { 0 };
+            (span_cmp, hash)
+        })
+        .unwrap()
+}
+
+/// Looks for query cycles starting from the last query in `jobs`.
+/// If a cycle is found, all queries in the cycle is removed from `jobs` and
+/// the function return true.
+/// If a cycle was not found, the starting query is removed from `jobs` and
+/// the function returns false.
+fn remove_cycle<'tcx>(
+    query_map: &QueryMap<'tcx>,
+    jobs: &mut Vec<QueryJobId>,
+    wakelist: &mut Vec<Arc<QueryWaiter<'tcx>>>,
+) -> bool {
+    let mut visited = FxHashSet::default();
+    let mut stack = Vec::new();
+    // Look for a cycle starting with the last query in `jobs`
+    if let Some(waiter) =
+        cycle_check(query_map, jobs.pop().unwrap(), DUMMY_SP, &mut stack, &mut visited)
+    {
+        // The stack is a vector of pairs of spans and queries; reverse it so that
+        // the earlier entries require later entries
+        let (mut spans, queries): (Vec<_>, Vec<_>) = stack.into_iter().rev().unzip();
+
+        // Shift the spans so that queries are matched with the span for their waitee
+        spans.rotate_right(1);
+
+        // Zip them back together
+        let mut stack: Vec<_> = iter::zip(spans, queries).collect();
+
+        // Remove the queries in our cycle from the list of jobs to look at
+        for r in &stack {
+            if let Some(pos) = jobs.iter().position(|j| j == &r.1) {
+                jobs.remove(pos);
+            }
+        }
+
+        // Find the queries in the cycle which are
+        // connected to queries outside the cycle
+        let entry_points = stack
+            .iter()
+            .filter_map(|&(span, query)| {
+                if query_job_id_parent(query, query_map).is_none() {
+                    // This query is connected to the root (it has no query parent)
+                    Some((span, query, None))
+                } else {
+                    let mut waiters = Vec::new();
+                    // Find all the direct waiters who lead to the root
+                    visit_waiters(query_map, query, |span, waiter| {
+                        // Mark all the other queries in the cycle as already visited
+                        let mut visited = FxHashSet::from_iter(stack.iter().map(|q| q.1));
+
+                        if connected_to_root(query_map, waiter, &mut visited) {
+                            waiters.push((span, waiter));
+                        }
+
+                        None
+                    });
+                    if waiters.is_empty() {
+                        None
+                    } else {
+                        // Deterministically pick one of the waiters to show to the user
+                        let waiter = *pick_query(query_map, &waiters, |s| *s);
+                        Some((span, query, Some(waiter)))
+                    }
+                }
+            })
+            .collect::<Vec<(Span, QueryJobId, Option<(Span, QueryJobId)>)>>();
+
+        // Deterministically pick an entry point
+        let (_, entry_point, usage) = pick_query(query_map, &entry_points, |e| (e.0, e.1));
+
+        // Shift the stack so that our entry point is first
+        let entry_point_pos = stack.iter().position(|(_, query)| query == entry_point);
+        if let Some(pos) = entry_point_pos {
+            stack.rotate_left(pos);
+        }
+
+        let usage =
+            usage.as_ref().map(|(span, query)| (*span, query_job_id_frame(*query, query_map)));
+
+        // Create the cycle error
+        let error = CycleError {
+            usage,
+            cycle: stack
+                .iter()
+                .map(|&(s, ref q)| QueryInfo { span: s, frame: query_job_id_frame(*q, query_map) })
+                .collect(),
+        };
+
+        // We unwrap `waiter` here since there must always be one
+        // edge which is resumable / waited using a query latch
+        let (waitee_query, waiter_idx) = waiter.unwrap();
+
+        // Extract the waiter we want to resume
+        let waiter =
+            query_job_id_latch(waitee_query, query_map).unwrap().extract_waiter(waiter_idx);
+
+        // Set the cycle error so it will be picked up when resumed
+        *waiter.cycle.lock() = Some(error);
+
+        // Put the waiter on the list of things to resume
+        wakelist.push(waiter);
+
+        true
+    } else {
+        false
+    }
+}
+
+/// Detects query cycles by using depth first search over all active query jobs.
+/// If a query cycle is found it will break the cycle by finding an edge which
+/// uses a query latch and then resuming that waiter.
+/// There may be multiple cycles involved in a deadlock, so this searches
+/// all active queries for cycles before finally resuming all the waiters at once.
+pub fn break_query_cycles<'tcx>(query_map: QueryMap<'tcx>, registry: &rustc_thread_pool::Registry) {
+    let mut wakelist = Vec::new();
+    // It is OK per the comments:
+    // - https://github.com/rust-lang/rust/pull/131200#issuecomment-2798854932
+    // - https://github.com/rust-lang/rust/pull/131200#issuecomment-2798866392
+    #[allow(rustc::potential_query_instability)]
+    let mut jobs: Vec<QueryJobId> = query_map.keys().cloned().collect();
+
+    let mut found_cycle = false;
+
+    while jobs.len() > 0 {
+        if remove_cycle(&query_map, &mut jobs, &mut wakelist) {
+            found_cycle = true;
+        }
+    }
+
+    // Check that a cycle was found. It is possible for a deadlock to occur without
+    // a query cycle if a query which can be waited on uses Rayon to do multithreading
+    // internally. Such a query (X) may be executing on 2 threads (A and B) and A may
+    // wait using Rayon on B. Rayon may then switch to executing another query (Y)
+    // which in turn will wait on X causing a deadlock. We have a false dependency from
+    // X to Y due to Rayon waiting and a true dependency from Y to X. The algorithm here
+    // only considers the true dependency and won't detect a cycle.
+    if !found_cycle {
+        panic!(
+            "deadlock detected as we're unable to find a query cycle to break\n\
+            current query map:\n{:#?}",
+            query_map
+        );
+    }
+
+    // Mark all the thread we're about to wake up as unblocked. This needs to be done before
+    // we wake the threads up as otherwise Rayon could detect a deadlock if a thread we
+    // resumed fell asleep and this thread had yet to mark the remaining threads as unblocked.
+    for _ in 0..wakelist.len() {
+        rustc_thread_pool::mark_unblocked(registry);
+    }
+
+    for waiter in wakelist.into_iter() {
+        waiter.condvar.notify_one();
+    }
+}
+
+pub fn print_query_stack<'tcx>(
+    qcx: QueryCtxt<'tcx>,
+    mut current_query: Option<QueryJobId>,
+    dcx: DiagCtxtHandle<'_>,
+    limit_frames: Option<usize>,
+    mut file: Option<std::fs::File>,
+) -> usize {
+    // Be careful relying on global state here: this code is called from
+    // a panic hook, which means that the global `DiagCtxt` may be in a weird
+    // state if it was responsible for triggering the panic.
+    let mut count_printed = 0;
+    let mut count_total = 0;
+
+    // Make use of a partial query map if we fail to take locks collecting active queries.
+    let query_map = match qcx.collect_active_jobs_from_all_queries(false) {
+        Ok(query_map) => query_map,
+        Err(query_map) => query_map,
+    };
+
+    if let Some(ref mut file) = file {
+        let _ = writeln!(file, "\n\nquery stack during panic:");
+    }
+    while let Some(query) = current_query {
+        let Some(query_info) = query_map.get(&query) else {
+            break;
+        };
+        let query_extra = query_info.frame.info.extract();
+        if Some(count_printed) < limit_frames || limit_frames.is_none() {
+            // Only print to stderr as many stack frames as `num_frames` when present.
+            dcx.struct_failure_note(format!(
+                "#{} [{:?}] {}",
+                count_printed, query_info.frame.dep_kind, query_extra.description
+            ))
+            .with_span(query_info.job.span)
+            .emit();
+            count_printed += 1;
+        }
+
+        if let Some(ref mut file) = file {
+            let _ = writeln!(
+                file,
+                "#{} [{}] {}",
+                count_total,
+                qcx.tcx.dep_kind_vtable(query_info.frame.dep_kind).name,
+                query_extra.description
+            );
+        }
+
+        current_query = query_info.job.parent;
+        count_total += 1;
+    }
+
+    if let Some(ref mut file) = file {
+        let _ = writeln!(file, "end of query stack");
+    }
+    count_total
+}
+
+#[inline(never)]
+#[cold]
+pub(crate) fn report_cycle<'a>(
+    sess: &'a Session,
+    CycleError { usage, cycle: stack }: &CycleError,
+) -> Diag<'a> {
+    assert!(!stack.is_empty());
+
+    let span = stack[0].frame.info.default_span(stack[1 % stack.len()].span);
+
+    let mut cycle_stack = Vec::new();
+
+    use crate::error::StackCount;
+    let stack_count = if stack.len() == 1 { StackCount::Single } else { StackCount::Multiple };
+
+    for i in 1..stack.len() {
+        let frame = &stack[i].frame;
+        let span = frame.info.default_span(stack[(i + 1) % stack.len()].span);
+        cycle_stack
+            .push(crate::error::CycleStack { span, desc: frame.info.description.to_owned() });
+    }
+
+    let mut cycle_usage = None;
+    if let Some((span, ref query)) = *usage {
+        cycle_usage = Some(crate::error::CycleUsage {
+            span: query.info.default_span(span),
+            usage: query.info.description.to_string(),
+        });
+    }
+
+    let alias =
+        if stack.iter().all(|entry| matches!(entry.frame.info.def_kind, Some(DefKind::TyAlias))) {
+            Some(crate::error::Alias::Ty)
+        } else if stack.iter().all(|entry| entry.frame.info.def_kind == Some(DefKind::TraitAlias)) {
+            Some(crate::error::Alias::Trait)
+        } else {
+            None
+        };
+
+    let cycle_diag = crate::error::Cycle {
+        span,
+        cycle_stack,
+        stack_bottom: stack[0].frame.info.description.to_owned(),
+        alias,
+        cycle_usage,
+        stack_count,
+        note_span: (),
+    };
+
+    sess.dcx().create_err(cycle_diag)
+}

compiler/rustc_query_impl/src/lib.rs

@@ -19,24 +19,27 @@ use rustc_middle::queries::{
 use rustc_middle::query::AsLocalKey;
 use rustc_middle::query::on_disk_cache::{CacheEncoder, EncodedDepNodeIndex, OnDiskCache};
 use rustc_middle::query::plumbing::{HashResult, QuerySystem, QuerySystemFns, QueryVTable};
-use rustc_middle::query::values::Value;
 use rustc_middle::ty::TyCtxt;
 use rustc_query_system::dep_graph::SerializedDepNodeIndex;
 use rustc_query_system::query::{
-    CycleError, CycleErrorHandling, QueryCache, QueryMap, QueryMode, QueryState,
+    CycleError, CycleErrorHandling, QueryCache, QueryMode, QueryState,
 };
 use rustc_span::{ErrorGuaranteed, Span};
 
+pub use crate::job::{QueryMap, break_query_cycles, print_query_stack};
 pub use crate::plumbing::{QueryCtxt, query_key_hash_verify_all};
 use crate::plumbing::{encode_all_query_results, try_mark_green};
 use crate::profiling_support::QueryKeyStringCache;
 pub use crate::profiling_support::alloc_self_profile_query_strings;
+use crate::values::Value;
 
 mod error;
 mod execution;
+mod job;
 #[macro_use]
 mod plumbing;
 mod profiling_support;
+mod values;
 
 #[derive(ConstParamTy)] // Allow this struct to be used for const-generic values.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]

compiler/rustc_query_impl/src/plumbing.rs

@@ -28,14 +28,15 @@ use rustc_middle::ty::tls::{self, ImplicitCtxt};
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_query_system::dep_graph::{DepNodeKey, FingerprintStyle, HasDepContext};
 use rustc_query_system::query::{
-    QueryCache, QueryContext, QueryJobId, QueryMap, QuerySideEffect, QueryStackDeferred,
-    QueryStackFrame, QueryStackFrameExtra,
+    QueryCache, QueryContext, QueryJobId, QuerySideEffect, QueryStackDeferred, QueryStackFrame,
+    QueryStackFrameExtra,
 };
 use rustc_serialize::{Decodable, Encodable};
 use rustc_span::def_id::LOCAL_CRATE;
 
 use crate::error::{QueryOverflow, QueryOverflowNote};
 use crate::execution::{all_inactive, force_query};
+use crate::job::{QueryMap, find_dep_kind_root};
 use crate::{QueryDispatcherUnerased, QueryFlags, SemiDynamicQueryDispatcher};
 
 /// Implements [`QueryContext`] for use by [`rustc_query_system`], since that
@@ -55,7 +56,7 @@ impl<'tcx> QueryCtxt<'tcx> {
         let query_map = self
             .collect_active_jobs_from_all_queries(true)
             .expect("failed to collect active queries");
-        let (info, depth) = job.find_dep_kind_root(query_map);
+        let (info, depth) = find_dep_kind_root(job, query_map);
 
         let suggested_limit = match self.tcx.recursion_limit() {
             Limit(0) => Limit(2),
@@ -116,6 +117,32 @@ impl<'tcx> QueryCtxt<'tcx> {
             tls::enter_context(&new_icx, compute)
         })
     }
+
+    /// Returns a map of currently active query jobs, collected from all queries.
+    ///
+    /// If `require_complete` is `true`, this function locks all shards of the
+    /// query results to produce a complete map, which always returns `Ok`.
+    /// Otherwise, it may return an incomplete map as an error if any shard
+    /// lock cannot be acquired.
+    ///
+    /// Prefer passing `false` to `require_complete` to avoid potential deadlocks,
+    /// especially when called from within a deadlock handler, unless a
+    /// complete map is needed and no deadlock is possible at this call site.
+    pub fn collect_active_jobs_from_all_queries(
+        self,
+        require_complete: bool,
+    ) -> Result<QueryMap<'tcx>, QueryMap<'tcx>> {
+        let mut jobs = QueryMap::default();
+        let mut complete = true;
+
+        for gather_fn in crate::PER_QUERY_GATHER_ACTIVE_JOBS_FNS.iter() {
+            if gather_fn(self.tcx, &mut jobs, require_complete).is_none() {
+                complete = false;
+            }
+        }
+
+        if complete { Ok(jobs) } else { Err(jobs) }
+    }
 }
 
 impl<'tcx> HasDepContext for QueryCtxt<'tcx> {
@@ -134,32 +161,6 @@ impl<'tcx> QueryContext<'tcx> for QueryCtxt<'tcx> {
         &self.tcx.jobserver_proxy
     }
 
-    /// Returns a map of currently active query jobs, collected from all queries.
-    ///
-    /// If `require_complete` is `true`, this function locks all shards of the
-    /// query results to produce a complete map, which always returns `Ok`.
-    /// Otherwise, it may return an incomplete map as an error if any shard
-    /// lock cannot be acquired.
-    ///
-    /// Prefer passing `false` to `require_complete` to avoid potential deadlocks,
-    /// especially when called from within a deadlock handler, unless a
-    /// complete map is needed and no deadlock is possible at this call site.
-    fn collect_active_jobs_from_all_queries(
-        self,
-        require_complete: bool,
-    ) -> Result<QueryMap<'tcx>, QueryMap<'tcx>> {
-        let mut jobs = QueryMap::default();
-        let mut complete = true;
-
-        for gather_fn in crate::PER_QUERY_GATHER_ACTIVE_JOBS_FNS.iter() {
-            if gather_fn(self.tcx, &mut jobs, require_complete).is_none() {
-                complete = false;
-            }
-        }
-
-        if complete { Ok(jobs) } else { Err(jobs) }
-    }
-
     // Interactions with on_disk_cache
     fn load_side_effect(
         self,

compiler/rustc_query_impl/src/values.rs

@@ -7,15 +7,17 @@ use rustc_errors::codes::*;
 use rustc_errors::{Applicability, MultiSpan, pluralize, struct_span_code_err};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_query_system::query::{CycleError, report_cycle};
+use rustc_middle::dep_graph::dep_kinds;
+use rustc_middle::query::plumbing::CyclePlaceholder;
+use rustc_middle::ty::{self, Representability, Ty, TyCtxt};
+use rustc_middle::{bug, span_bug};
+use rustc_query_system::query::CycleError;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{ErrorGuaranteed, Span};
 
-use crate::dep_graph::dep_kinds;
-use crate::query::plumbing::CyclePlaceholder;
-use crate::ty::{self, Representability, Ty, TyCtxt};
+use crate::job::report_cycle;
 
-pub trait Value<'tcx>: Sized {
+pub(crate) trait Value<'tcx>: Sized {
     fn from_cycle_error(tcx: TyCtxt<'tcx>, cycle_error: &CycleError, guar: ErrorGuaranteed)
     -> Self;
 }

compiler/rustc_query_system/src/error.rs

@@ -1,62 +1,4 @@
-use rustc_errors::codes::*;
-use rustc_macros::{Diagnostic, Subdiagnostic};
-use rustc_span::Span;
-
-#[derive(Subdiagnostic)]
-#[note("...which requires {$desc}...")]
-pub(crate) struct CycleStack {
-    #[primary_span]
-    pub span: Span,
-    pub desc: String,
-}
-
-#[derive(Subdiagnostic)]
-pub(crate) enum StackCount {
-    #[note("...which immediately requires {$stack_bottom} again")]
-    Single,
-    #[note("...which again requires {$stack_bottom}, completing the cycle")]
-    Multiple,
-}
-
-#[derive(Subdiagnostic)]
-pub(crate) enum Alias {
-    #[note("type aliases cannot be recursive")]
-    #[help("consider using a struct, enum, or union instead to break the cycle")]
-    #[help(
-        "see <https://doc.rust-lang.org/reference/types.html#recursive-types> for more information"
-    )]
-    Ty,
-    #[note("trait aliases cannot be recursive")]
-    Trait,
-}
-
-#[derive(Subdiagnostic)]
-#[note("cycle used when {$usage}")]
-pub(crate) struct CycleUsage {
-    #[primary_span]
-    pub span: Span,
-    pub usage: String,
-}
-
-#[derive(Diagnostic)]
-#[diag("cycle detected when {$stack_bottom}", code = E0391)]
-pub(crate) struct Cycle {
-    #[primary_span]
-    pub span: Span,
-    pub stack_bottom: String,
-    #[subdiagnostic]
-    pub cycle_stack: Vec<CycleStack>,
-    #[subdiagnostic]
-    pub stack_count: StackCount,
-    #[subdiagnostic]
-    pub alias: Option<Alias>,
-    #[subdiagnostic]
-    pub cycle_usage: Option<CycleUsage>,
-    #[note(
-        "see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information"
-    )]
-    pub note_span: (),
-}
+use rustc_macros::Diagnostic;
 
 #[derive(Diagnostic)]
 #[diag("internal compiler error: reentrant incremental verify failure, suppressing message")]

compiler/rustc_query_system/src/query/caches.rs

@@ -21,9 +21,6 @@ pub trait QueryCacheKey = Hash + Eq + Copy + Debug + for<'a> HashStable<StableHa
 /// Types implementing this trait are associated with actual key/value types
 /// by the `Cache` associated type of the `rustc_middle::query::Key` trait.
 pub trait QueryCache: Sized {
-    // `Key` and `Value` are `Copy` instead of `Clone` to ensure copying them stays cheap,
-    // but it isn't strictly necessary.
-    // FIXME: Is that comment still true?
     type Key: QueryCacheKey;
     type Value: Copy;
 

compiler/rustc_query_system/src/query/job.rs

@@ -1,20 +1,12 @@
 use std::fmt::Debug;
 use std::hash::Hash;
-use std::io::Write;
-use std::iter;
 use std::num::NonZero;
 use std::sync::Arc;
 
 use parking_lot::{Condvar, Mutex};
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_errors::{Diag, DiagCtxtHandle};
-use rustc_hir::def::DefKind;
-use rustc_session::Session;
-use rustc_span::{DUMMY_SP, Span};
+use rustc_span::Span;
 
 use super::{QueryStackDeferred, QueryStackFrameExtra};
-use crate::dep_graph::DepContext;
-use crate::error::CycleStack;
 use crate::query::plumbing::CycleError;
 use crate::query::{QueryContext, QueryStackFrame};
 
@@ -32,38 +24,10 @@ impl<'tcx> QueryInfo<QueryStackDeferred<'tcx>> {
     }
 }
 
-/// Map from query job IDs to job information collected by
-/// [`QueryContext::collect_active_jobs_from_all_queries`].
-pub type QueryMap<'tcx> = FxHashMap<QueryJobId, QueryJobInfo<'tcx>>;
-
 /// A value uniquely identifying an active query job.
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
 pub struct QueryJobId(pub NonZero<u64>);
 
-impl QueryJobId {
-    fn frame<'a, 'tcx>(self, map: &'a QueryMap<'tcx>) -> QueryStackFrame<QueryStackDeferred<'tcx>> {
-        map.get(&self).unwrap().frame.clone()
-    }
-
-    fn span<'a, 'tcx>(self, map: &'a QueryMap<'tcx>) -> Span {
-        map.get(&self).unwrap().job.span
-    }
-
-    fn parent<'a, 'tcx>(self, map: &'a QueryMap<'tcx>) -> Option<QueryJobId> {
-        map.get(&self).unwrap().job.parent
-    }
-
-    fn latch<'a, 'tcx>(self, map: &'a QueryMap<'tcx>) -> Option<&'a QueryLatch<'tcx>> {
-        map.get(&self).unwrap().job.latch.as_ref()
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct QueryJobInfo<'tcx> {
-    pub frame: QueryStackFrame<QueryStackDeferred<'tcx>>,
-    pub job: QueryJob<'tcx>,
-}
-
 /// Represents an active query job.
 #[derive(Clone, Debug)]
 pub struct QueryJob<'tcx> {
@@ -76,7 +40,7 @@ pub struct QueryJob<'tcx> {
     pub parent: Option<QueryJobId>,
 
     /// The latch that is used to wait on this job.
-    latch: Option<QueryLatch<'tcx>>,
+    pub latch: Option<QueryLatch<'tcx>>,
 }
 
 impl<'tcx> QueryJob<'tcx> {
@@ -105,91 +69,23 @@ impl<'tcx> QueryJob<'tcx> {
     }
 }
 
-impl QueryJobId {
-    pub fn find_cycle_in_stack<'tcx>(
-        &self,
-        query_map: QueryMap<'tcx>,
-        current_job: &Option<QueryJobId>,
-        span: Span,
-    ) -> CycleError<QueryStackDeferred<'tcx>> {
-        // Find the waitee amongst `current_job` parents
-        let mut cycle = Vec::new();
-        let mut current_job = Option::clone(current_job);
-
-        while let Some(job) = current_job {
-            let info = query_map.get(&job).unwrap();
-            cycle.push(QueryInfo { span: info.job.span, frame: info.frame.clone() });
-
-            if job == *self {
-                cycle.reverse();
-
-                // This is the end of the cycle
-                // The span entry we included was for the usage
-                // of the cycle itself, and not part of the cycle
-                // Replace it with the span which caused the cycle to form
-                cycle[0].span = span;
-                // Find out why the cycle itself was used
-                let usage = info
-                    .job
-                    .parent
-                    .as_ref()
-                    .map(|parent| (info.job.span, parent.frame(&query_map)));
-                return CycleError { usage, cycle };
-            }
-
-            current_job = info.job.parent;
-        }
-
-        panic!("did not find a cycle")
-    }
-
-    #[cold]
-    #[inline(never)]
-    pub fn find_dep_kind_root<'tcx>(
-        &self,
-        query_map: QueryMap<'tcx>,
-    ) -> (QueryJobInfo<'tcx>, usize) {
-        let mut depth = 1;
-        let info = query_map.get(&self).unwrap();
-        let dep_kind = info.frame.dep_kind;
-        let mut current_id = info.job.parent;
-        let mut last_layout = (info.clone(), depth);
-
-        while let Some(id) = current_id {
-            let info = query_map.get(&id).unwrap();
-            if info.frame.dep_kind == dep_kind {
-                depth += 1;
-                last_layout = (info.clone(), depth);
-            }
-            current_id = info.job.parent;
-        }
-        last_layout
-    }
+#[derive(Debug)]
+pub struct QueryWaiter<'tcx> {
+    pub query: Option<QueryJobId>,
+    pub condvar: Condvar,
+    pub span: Span,
+    pub cycle: Mutex<Option<CycleError<QueryStackDeferred<'tcx>>>>,
 }
 
 #[derive(Debug)]
-struct QueryWaiter<'tcx> {
-    query: Option<QueryJobId>,
-    condvar: Condvar,
-    span: Span,
-    cycle: Mutex<Option<CycleError<QueryStackDeferred<'tcx>>>>,
+pub struct QueryLatchInfo<'tcx> {
+    pub complete: bool,
+    pub waiters: Vec<Arc<QueryWaiter<'tcx>>>,
 }
 
-#[derive(Debug)]
-struct QueryLatchInfo<'tcx> {
-    complete: bool,
-    waiters: Vec<Arc<QueryWaiter<'tcx>>>,
-}
-
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub struct QueryLatch<'tcx> {
-    info: Arc<Mutex<QueryLatchInfo<'tcx>>>,
-}
-
-impl<'tcx> Clone for QueryLatch<'tcx> {
-    fn clone(&self) -> Self {
-        Self { info: Arc::clone(&self.info) }
-    }
+    pub info: Arc<Mutex<QueryLatchInfo<'tcx>>>,
 }
 
 impl<'tcx> QueryLatch<'tcx> {
@@ -256,399 +152,10 @@ impl<'tcx> QueryLatch<'tcx> {
 
     /// Removes a single waiter from the list of waiters.
     /// This is used to break query cycles.
-    fn extract_waiter(&self, waiter: usize) -> Arc<QueryWaiter<'tcx>> {
+    pub fn extract_waiter(&self, waiter: usize) -> Arc<QueryWaiter<'tcx>> {
         let mut info = self.info.lock();
         debug_assert!(!info.complete);
         // Remove the waiter from the list of waiters
         info.waiters.remove(waiter)
     }
 }
-
-/// A resumable waiter of a query. The usize is the index into waiters in the query's latch
-type Waiter = (QueryJobId, usize);
-
-/// Visits all the non-resumable and resumable waiters of a query.
-/// Only waiters in a query are visited.
-/// `visit` is called for every waiter and is passed a query waiting on `query_ref`
-/// and a span indicating the reason the query waited on `query_ref`.
-/// If `visit` returns Some, this function returns.
-/// For visits of non-resumable waiters it returns the return value of `visit`.
-/// For visits of resumable waiters it returns Some(Some(Waiter)) which has the
-/// required information to resume the waiter.
-/// If all `visit` calls returns None, this function also returns None.
-fn visit_waiters<'tcx, F>(
-    query_map: &QueryMap<'tcx>,
-    query: QueryJobId,
-    mut visit: F,
-) -> Option<Option<Waiter>>
-where
-    F: FnMut(Span, QueryJobId) -> Option<Option<Waiter>>,
-{
-    // Visit the parent query which is a non-resumable waiter since it's on the same stack
-    if let Some(parent) = query.parent(query_map)
-        && let Some(cycle) = visit(query.span(query_map), parent)
-    {
-        return Some(cycle);
-    }
-
-    // Visit the explicit waiters which use condvars and are resumable
-    if let Some(latch) = query.latch(query_map) {
-        for (i, waiter) in latch.info.lock().waiters.iter().enumerate() {
-            if let Some(waiter_query) = waiter.query {
-                if visit(waiter.span, waiter_query).is_some() {
-                    // Return a value which indicates that this waiter can be resumed
-                    return Some(Some((query, i)));
-                }
-            }
-        }
-    }
-
-    None
-}
-
-/// Look for query cycles by doing a depth first search starting at `query`.
-/// `span` is the reason for the `query` to execute. This is initially DUMMY_SP.
-/// If a cycle is detected, this initial value is replaced with the span causing
-/// the cycle.
-fn cycle_check<'tcx>(
-    query_map: &QueryMap<'tcx>,
-    query: QueryJobId,
-    span: Span,
-    stack: &mut Vec<(Span, QueryJobId)>,
-    visited: &mut FxHashSet<QueryJobId>,
-) -> Option<Option<Waiter>> {
-    if !visited.insert(query) {
-        return if let Some(p) = stack.iter().position(|q| q.1 == query) {
-            // We detected a query cycle, fix up the initial span and return Some
-
-            // Remove previous stack entries
-            stack.drain(0..p);
-            // Replace the span for the first query with the cycle cause
-            stack[0].0 = span;
-            Some(None)
-        } else {
-            None
-        };
-    }
-
-    // Query marked as visited is added it to the stack
-    stack.push((span, query));
-
-    // Visit all the waiters
-    let r = visit_waiters(query_map, query, |span, successor| {
-        cycle_check(query_map, successor, span, stack, visited)
-    });
-
-    // Remove the entry in our stack if we didn't find a cycle
-    if r.is_none() {
-        stack.pop();
-    }
-
-    r
-}
-
-/// Finds out if there's a path to the compiler root (aka. code which isn't in a query)
-/// from `query` without going through any of the queries in `visited`.
-/// This is achieved with a depth first search.
-fn connected_to_root<'tcx>(
-    query_map: &QueryMap<'tcx>,
-    query: QueryJobId,
-    visited: &mut FxHashSet<QueryJobId>,
-) -> bool {
-    // We already visited this or we're deliberately ignoring it
-    if !visited.insert(query) {
-        return false;
-    }
-
-    // This query is connected to the root (it has no query parent), return true
-    if query.parent(query_map).is_none() {
-        return true;
-    }
-
-    visit_waiters(query_map, query, |_, successor| {
-        connected_to_root(query_map, successor, visited).then_some(None)
-    })
-    .is_some()
-}
-
-// Deterministically pick an query from a list
-fn pick_query<'a, 'tcx, T, F>(query_map: &QueryMap<'tcx>, queries: &'a [T], f: F) -> &'a T
-where
-    F: Fn(&T) -> (Span, QueryJobId),
-{
-    // Deterministically pick an entry point
-    // FIXME: Sort this instead
-    queries
-        .iter()
-        .min_by_key(|v| {
-            let (span, query) = f(v);
-            let hash = query.frame(query_map).hash;
-            // Prefer entry points which have valid spans for nicer error messages
-            // We add an integer to the tuple ensuring that entry points
-            // with valid spans are picked first
-            let span_cmp = if span == DUMMY_SP { 1 } else { 0 };
-            (span_cmp, hash)
-        })
-        .unwrap()
-}
-
-/// Looks for query cycles starting from the last query in `jobs`.
-/// If a cycle is found, all queries in the cycle is removed from `jobs` and
-/// the function return true.
-/// If a cycle was not found, the starting query is removed from `jobs` and
-/// the function returns false.
-fn remove_cycle<'tcx>(
-    query_map: &QueryMap<'tcx>,
-    jobs: &mut Vec<QueryJobId>,
-    wakelist: &mut Vec<Arc<QueryWaiter<'tcx>>>,
-) -> bool {
-    let mut visited = FxHashSet::default();
-    let mut stack = Vec::new();
-    // Look for a cycle starting with the last query in `jobs`
-    if let Some(waiter) =
-        cycle_check(query_map, jobs.pop().unwrap(), DUMMY_SP, &mut stack, &mut visited)
-    {
-        // The stack is a vector of pairs of spans and queries; reverse it so that
-        // the earlier entries require later entries
-        let (mut spans, queries): (Vec<_>, Vec<_>) = stack.into_iter().rev().unzip();
-
-        // Shift the spans so that queries are matched with the span for their waitee
-        spans.rotate_right(1);
-
-        // Zip them back together
-        let mut stack: Vec<_> = iter::zip(spans, queries).collect();
-
-        // Remove the queries in our cycle from the list of jobs to look at
-        for r in &stack {
-            if let Some(pos) = jobs.iter().position(|j| j == &r.1) {
-                jobs.remove(pos);
-            }
-        }
-
-        // Find the queries in the cycle which are
-        // connected to queries outside the cycle
-        let entry_points = stack
-            .iter()
-            .filter_map(|&(span, query)| {
-                if query.parent(query_map).is_none() {
-                    // This query is connected to the root (it has no query parent)
-                    Some((span, query, None))
-                } else {
-                    let mut waiters = Vec::new();
-                    // Find all the direct waiters who lead to the root
-                    visit_waiters(query_map, query, |span, waiter| {
-                        // Mark all the other queries in the cycle as already visited
-                        let mut visited = FxHashSet::from_iter(stack.iter().map(|q| q.1));
-
-                        if connected_to_root(query_map, waiter, &mut visited) {
-                            waiters.push((span, waiter));
-                        }
-
-                        None
-                    });
-                    if waiters.is_empty() {
-                        None
-                    } else {
-                        // Deterministically pick one of the waiters to show to the user
-                        let waiter = *pick_query(query_map, &waiters, |s| *s);
-                        Some((span, query, Some(waiter)))
-                    }
-                }
-            })
-            .collect::<Vec<(Span, QueryJobId, Option<(Span, QueryJobId)>)>>();
-
-        // Deterministically pick an entry point
-        let (_, entry_point, usage) = pick_query(query_map, &entry_points, |e| (e.0, e.1));
-
-        // Shift the stack so that our entry point is first
-        let entry_point_pos = stack.iter().position(|(_, query)| query == entry_point);
-        if let Some(pos) = entry_point_pos {
-            stack.rotate_left(pos);
-        }
-
-        let usage = usage.as_ref().map(|(span, query)| (*span, query.frame(query_map)));
-
-        // Create the cycle error
-        let error = CycleError {
-            usage,
-            cycle: stack
-                .iter()
-                .map(|&(s, ref q)| QueryInfo { span: s, frame: q.frame(query_map) })
-                .collect(),
-        };
-
-        // We unwrap `waiter` here since there must always be one
-        // edge which is resumable / waited using a query latch
-        let (waitee_query, waiter_idx) = waiter.unwrap();
-
-        // Extract the waiter we want to resume
-        let waiter = waitee_query.latch(query_map).unwrap().extract_waiter(waiter_idx);
-
-        // Set the cycle error so it will be picked up when resumed
-        *waiter.cycle.lock() = Some(error);
-
-        // Put the waiter on the list of things to resume
-        wakelist.push(waiter);
-
-        true
-    } else {
-        false
-    }
-}
-
-/// Detects query cycles by using depth first search over all active query jobs.
-/// If a query cycle is found it will break the cycle by finding an edge which
-/// uses a query latch and then resuming that waiter.
-/// There may be multiple cycles involved in a deadlock, so this searches
-/// all active queries for cycles before finally resuming all the waiters at once.
-pub fn break_query_cycles<'tcx>(query_map: QueryMap<'tcx>, registry: &rustc_thread_pool::Registry) {
-    let mut wakelist = Vec::new();
-    // It is OK per the comments:
-    // - https://github.com/rust-lang/rust/pull/131200#issuecomment-2798854932
-    // - https://github.com/rust-lang/rust/pull/131200#issuecomment-2798866392
-    #[allow(rustc::potential_query_instability)]
-    let mut jobs: Vec<QueryJobId> = query_map.keys().cloned().collect();
-
-    let mut found_cycle = false;
-
-    while jobs.len() > 0 {
-        if remove_cycle(&query_map, &mut jobs, &mut wakelist) {
-            found_cycle = true;
-        }
-    }
-
-    // Check that a cycle was found. It is possible for a deadlock to occur without
-    // a query cycle if a query which can be waited on uses Rayon to do multithreading
-    // internally. Such a query (X) may be executing on 2 threads (A and B) and A may
-    // wait using Rayon on B. Rayon may then switch to executing another query (Y)
-    // which in turn will wait on X causing a deadlock. We have a false dependency from
-    // X to Y due to Rayon waiting and a true dependency from Y to X. The algorithm here
-    // only considers the true dependency and won't detect a cycle.
-    if !found_cycle {
-        panic!(
-            "deadlock detected as we're unable to find a query cycle to break\n\
-            current query map:\n{:#?}",
-            query_map
-        );
-    }
-
-    // Mark all the thread we're about to wake up as unblocked. This needs to be done before
-    // we wake the threads up as otherwise Rayon could detect a deadlock if a thread we
-    // resumed fell asleep and this thread had yet to mark the remaining threads as unblocked.
-    for _ in 0..wakelist.len() {
-        rustc_thread_pool::mark_unblocked(registry);
-    }
-
-    for waiter in wakelist.into_iter() {
-        waiter.condvar.notify_one();
-    }
-}
-
-#[inline(never)]
-#[cold]
-pub fn report_cycle<'a>(
-    sess: &'a Session,
-    CycleError { usage, cycle: stack }: &CycleError,
-) -> Diag<'a> {
-    assert!(!stack.is_empty());
-
-    let span = stack[0].frame.info.default_span(stack[1 % stack.len()].span);
-
-    let mut cycle_stack = Vec::new();
-
-    use crate::error::StackCount;
-    let stack_count = if stack.len() == 1 { StackCount::Single } else { StackCount::Multiple };
-
-    for i in 1..stack.len() {
-        let frame = &stack[i].frame;
-        let span = frame.info.default_span(stack[(i + 1) % stack.len()].span);
-        cycle_stack.push(CycleStack { span, desc: frame.info.description.to_owned() });
-    }
-
-    let mut cycle_usage = None;
-    if let Some((span, ref query)) = *usage {
-        cycle_usage = Some(crate::error::CycleUsage {
-            span: query.info.default_span(span),
-            usage: query.info.description.to_string(),
-        });
-    }
-
-    let alias =
-        if stack.iter().all(|entry| matches!(entry.frame.info.def_kind, Some(DefKind::TyAlias))) {
-            Some(crate::error::Alias::Ty)
-        } else if stack.iter().all(|entry| entry.frame.info.def_kind == Some(DefKind::TraitAlias)) {
-            Some(crate::error::Alias::Trait)
-        } else {
-            None
-        };
-
-    let cycle_diag = crate::error::Cycle {
-        span,
-        cycle_stack,
-        stack_bottom: stack[0].frame.info.description.to_owned(),
-        alias,
-        cycle_usage,
-        stack_count,
-        note_span: (),
-    };
-
-    sess.dcx().create_err(cycle_diag)
-}
-
-pub fn print_query_stack<'tcx, Qcx: QueryContext<'tcx>>(
-    qcx: Qcx,
-    mut current_query: Option<QueryJobId>,
-    dcx: DiagCtxtHandle<'_>,
-    limit_frames: Option<usize>,
-    mut file: Option<std::fs::File>,
-) -> usize {
-    // Be careful relying on global state here: this code is called from
-    // a panic hook, which means that the global `DiagCtxt` may be in a weird
-    // state if it was responsible for triggering the panic.
-    let mut count_printed = 0;
-    let mut count_total = 0;
-
-    // Make use of a partial query map if we fail to take locks collecting active queries.
-    let query_map = match qcx.collect_active_jobs_from_all_queries(false) {
-        Ok(query_map) => query_map,
-        Err(query_map) => query_map,
-    };
-
-    if let Some(ref mut file) = file {
-        let _ = writeln!(file, "\n\nquery stack during panic:");
-    }
-    while let Some(query) = current_query {
-        let Some(query_info) = query_map.get(&query) else {
-            break;
-        };
-        let query_extra = query_info.frame.info.extract();
-        if Some(count_printed) < limit_frames || limit_frames.is_none() {
-            // Only print to stderr as many stack frames as `num_frames` when present.
-            dcx.struct_failure_note(format!(
-                "#{} [{:?}] {}",
-                count_printed, query_info.frame.dep_kind, query_extra.description
-            ))
-            .with_span(query_info.job.span)
-            .emit();
-            count_printed += 1;
-        }
-
-        if let Some(ref mut file) = file {
-            let _ = writeln!(
-                file,
-                "#{} [{}] {}",
-                count_total,
-                qcx.dep_context().dep_kind_vtable(query_info.frame.dep_kind).name,
-                query_extra.description
-            );
-        }
-
-        current_query = query_info.job.parent;
-        count_total += 1;
-    }
-
-    if let Some(ref mut file) = file {
-        let _ = writeln!(file, "end of query stack");
-    }
-    count_total
-}

compiler/rustc_query_system/src/query/mod.rs

@@ -15,10 +15,7 @@ use rustc_span::def_id::DefId;
 pub use self::caches::{
     DefIdCache, DefaultCache, QueryCache, QueryCacheKey, SingleCache, VecCache,
 };
-pub use self::job::{
-    QueryInfo, QueryJob, QueryJobId, QueryJobInfo, QueryLatch, QueryMap, break_query_cycles,
-    print_query_stack, report_cycle,
-};
+pub use self::job::{QueryInfo, QueryJob, QueryJobId, QueryLatch, QueryWaiter};
 pub use self::plumbing::*;
 use crate::dep_graph::{DepKind, DepNodeIndex, HasDepContext, SerializedDepNodeIndex};
 
@@ -52,7 +49,7 @@ pub struct QueryStackFrame<I> {
     pub dep_kind: DepKind,
     /// This hash is used to deterministically pick
     /// a query to remove cycles in the parallel compiler.
-    hash: Hash64,
+    pub hash: Hash64,
     pub def_id: Option<DefId>,
     /// A def-id that is extracted from a `Ty` in a query key
     pub def_id_for_ty_in_cycle: Option<DefId>,
@@ -161,11 +158,6 @@ pub trait QueryContext<'tcx>: HasDepContext {
     /// a token while waiting on a query.
     fn jobserver_proxy(&self) -> &Proxy;
 
-    fn collect_active_jobs_from_all_queries(
-        self,
-        require_complete: bool,
-    ) -> Result<QueryMap<'tcx>, QueryMap<'tcx>>;
-
     /// Load a side effect associated to the node in the previous session.
     fn load_side_effect(
         self,

compiler/rustc_target/src/spec/targets/aarch64_apple_tvos.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target,
         metadata: TargetMetadata {
             description: Some("ARM64 Apple tvOS".into()),
-            tier: Some(3),
+            tier: Some(2),
             host_tools: Some(false),
             std: Some(true),
         },

compiler/rustc_target/src/spec/targets/aarch64_apple_tvos_sim.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target,
         metadata: TargetMetadata {
             description: Some("ARM64 Apple tvOS Simulator".into()),
-            tier: Some(3),
+            tier: Some(2),
             host_tools: Some(false),
             std: Some(true),
         },

compiler/rustc_target/src/spec/targets/aarch64_apple_visionos.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target,
         metadata: TargetMetadata {
             description: Some("ARM64 Apple visionOS".into()),
-            tier: Some(3),
+            tier: Some(2),
             host_tools: Some(false),
             std: Some(true),
         },

compiler/rustc_target/src/spec/targets/aarch64_apple_visionos_sim.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target,
         metadata: TargetMetadata {
             description: Some("ARM64 Apple visionOS simulator".into()),
-            tier: Some(3),
+            tier: Some(2),
             host_tools: Some(false),
             std: Some(true),
         },

compiler/rustc_target/src/spec/targets/aarch64_apple_watchos.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target,
         metadata: TargetMetadata {
             description: Some("ARM64 Apple watchOS".into()),
-            tier: Some(3),
+            tier: Some(2),
             host_tools: Some(false),
             std: Some(true),
         },

compiler/rustc_target/src/spec/targets/aarch64_apple_watchos_sim.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target,
         metadata: TargetMetadata {
             description: Some("ARM64 Apple watchOS Simulator".into()),
-            tier: Some(3),
+            tier: Some(2),
             host_tools: Some(false),
             std: Some(true),
         },

compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs

@@ -190,8 +190,8 @@ impl<'tcx> Visitor<'tcx> for TyPathVisitor<'tcx> {
             }
 
             Some(rbv::ResolvedArg::LateBound(debruijn_index, _, id)) => {
-                debug!("FindNestedTypeVisitor::visit_ty: LateBound depth = {:?}", debruijn_index,);
-                debug!("id={:?}", id);
+                debug!("FindNestedTypeVisitor::visit_ty: LateBound depth = {debruijn_index:?}");
+                debug!("id={id:?}");
                 if debruijn_index == self.current_index && id.to_def_id() == self.region_def_id {
                     return ControlFlow::Break(());
                 }

compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs

@@ -239,14 +239,14 @@ pub fn suggest_new_region_bound(
                         };
                         spans_suggs.push((fn_return.span.shrink_to_hi(), format!(" + {name} ")));
                         err.multipart_suggestion_verbose(
-                            format!("{declare} `{ty}` {captures}, {use_lt}",),
+                            format!("{declare} `{ty}` {captures}, {use_lt}"),
                             spans_suggs,
                             Applicability::MaybeIncorrect,
                         );
                     } else {
                         err.span_suggestion_verbose(
                             fn_return.span.shrink_to_hi(),
-                            format!("{declare} `{ty}` {captures}, {explicit}",),
+                            format!("{declare} `{ty}` {captures}, {explicit}"),
                             &plus_lt,
                             Applicability::MaybeIncorrect,
                         );
@@ -257,7 +257,7 @@ pub fn suggest_new_region_bound(
                 if let LifetimeKind::ImplicitObjectLifetimeDefault = lt.kind {
                     err.span_suggestion_verbose(
                         fn_return.span.shrink_to_hi(),
-                        format!("{declare} the trait object {captures}, {explicit}",),
+                        format!("{declare} the trait object {captures}, {explicit}"),
                         &plus_lt,
                         Applicability::MaybeIncorrect,
                     );

compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs

@@ -710,7 +710,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             predicate
         );
         let post = if post.len() > 1 || (post.len() == 1 && post[0].contains('\n')) {
-            format!(":\n{}", post.iter().map(|p| format!("- {p}")).collect::<Vec<_>>().join("\n"),)
+            format!(":\n{}", post.iter().map(|p| format!("- {p}")).collect::<Vec<_>>().join("\n"))
         } else if post.len() == 1 {
             format!(": `{}`", post[0])
         } else {
@@ -722,7 +722,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 err.note(format!("cannot satisfy `{predicate}`"));
             }
             (0, _, 1) => {
-                err.note(format!("{} in the `{}` crate{}", msg, crates[0], post,));
+                err.note(format!("{msg} in the `{}` crate{post}", crates[0]));
             }
             (0, _, _) => {
                 err.note(format!(
@@ -739,7 +739,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             (_, 1, 1) => {
                 let span: MultiSpan = spans.into();
                 err.span_note(span, msg);
-                err.note(format!("and another `impl` found in the `{}` crate{}", crates[0], post,));
+                err.note(format!("and another `impl` found in the `{}` crate{post}", crates[0]));
             }
             _ => {
                 let span: MultiSpan = spans.into();

compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs

@@ -2263,7 +2263,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 err.highlighted_span_help(
                     self.tcx.def_span(def_id),
                     vec![
-                        StringPart::normal(format!("the trait `{trait_}` ",)),
+                        StringPart::normal(format!("the trait `{trait_}` ")),
                         StringPart::highlighted("is"),
                         StringPart::normal(desc),
                         StringPart::highlighted(self_ty),

compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs

@@ -888,7 +888,7 @@ impl<'tcx> OnUnimplementedFormatString {
                     }
                 } else {
                     let reported =
-                        struct_span_code_err!(tcx.dcx(), self.span, E0231, "{}", e.description,)
+                        struct_span_code_err!(tcx.dcx(), self.span, E0231, "{}", e.description)
                             .emit();
                     result = Err(reported);
                 }

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -312,7 +312,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             // `async`/`gen` constructs get lowered to a special kind of coroutine that
             // should *not* `impl Coroutine`.
             ty::Coroutine(did, ..) if self.tcx().is_general_coroutine(*did) => {
-                debug!(?self_ty, ?obligation, "assemble_coroutine_candidates",);
+                debug!(?self_ty, ?obligation, "assemble_coroutine_candidates");
 
                 candidates.vec.push(CoroutineCandidate);
             }
@@ -334,7 +334,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             // async constructs get lowered to a special kind of coroutine that
             // should directly `impl Future`.
             if self.tcx().coroutine_is_async(*did) {
-                debug!(?self_ty, ?obligation, "assemble_future_candidates",);
+                debug!(?self_ty, ?obligation, "assemble_future_candidates");
 
                 candidates.vec.push(FutureCandidate);
             }
@@ -352,7 +352,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         if let ty::Coroutine(did, ..) = self_ty.kind()
             && self.tcx().coroutine_is_gen(*did)
         {
-            debug!(?self_ty, ?obligation, "assemble_iterator_candidates",);
+            debug!(?self_ty, ?obligation, "assemble_iterator_candidates");
 
             candidates.vec.push(IteratorCandidate);
         }
@@ -378,7 +378,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             // gen constructs get lowered to a special kind of coroutine that
             // should directly `impl AsyncIterator`.
             if self.tcx().coroutine_is_async_gen(did) {
-                debug!(?self_ty, ?obligation, "assemble_iterator_candidates",);
+                debug!(?self_ty, ?obligation, "assemble_iterator_candidates");
 
                 // Can only confirm this candidate if we have constrained
                 // the `Yield` type to at least `Poll<Option<?0>>`..

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -1246,6 +1246,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         })
     }
 
+    /// This trait is indirectly exposed on stable, so do *not* extend the set of types that
+    /// implement the trait without FCP!
     fn confirm_bikeshed_guaranteed_no_drop_candidate(
         &mut self,
         obligation: &PolyTraitObligation<'tcx>,

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1223,7 +1223,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     && self.match_fresh_trait_preds(stack.fresh_trait_pred, prev.fresh_trait_pred)
             })
         {
-            debug!("evaluate_stack --> unbound argument, recursive --> giving up",);
+            debug!("evaluate_stack --> unbound argument, recursive --> giving up");
             return Ok(EvaluatedToAmbigStackDependent);
         }
 

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -951,6 +951,34 @@ impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for WfPredicates<'a, 'tcx> {
                         ty::Binder::dummy(ty::PredicateKind::DynCompatible(principal)),
                     ));
                 }
+
+                if !t.has_escaping_bound_vars() {
+                    for projection in data.projection_bounds() {
+                        let pred_binder = projection
+                            .with_self_ty(tcx, t)
+                            .map_bound(|p| {
+                                p.term.as_const().map(|ct| {
+                                    let assoc_const_ty = tcx
+                                        .type_of(p.projection_term.def_id)
+                                        .instantiate(tcx, p.projection_term.args);
+                                    ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(
+                                        ct,
+                                        assoc_const_ty,
+                                    ))
+                                })
+                            })
+                            .transpose();
+                        if let Some(pred_binder) = pred_binder {
+                            self.out.push(traits::Obligation::with_depth(
+                                tcx,
+                                self.cause(ObligationCauseCode::WellFormed(None)),
+                                self.recursion_depth,
+                                self.param_env,
+                                pred_binder,
+                            ));
+                        }
+                    }
+                }
             }
 
             // Inference variables are the complicated case, since we don't

library/core/src/array/drain.rs

@@ -31,7 +31,6 @@ impl<'l, 'f, T, U, const N: usize, F: FnMut(T) -> U> Drain<'l, 'f, T, N, F> {
 }
 
 /// See [`Drain::new`]; this is our fake iterator.
-#[rustc_const_unstable(feature = "array_try_map", issue = "79711")]
 #[unstable(feature = "array_try_map", issue = "79711")]
 pub(super) struct Drain<'l, 'f, T, const N: usize, F> {
     // FIXME(const-hack): This is essentially a slice::IterMut<'static>, replace when possible.

src/ci/github-actions/jobs.yml

@@ -466,10 +466,34 @@ auto:
 
   - name: dist-apple-various
     env:
-      SCRIPT: ./x.py dist bootstrap --include-default-paths --host='' --target=aarch64-apple-ios,x86_64-apple-ios,aarch64-apple-ios-sim,aarch64-apple-ios-macabi,x86_64-apple-ios-macabi
+      # Build and distribute the standard library for these targets.
+      TARGETS: "aarch64-apple-ios,\
+        aarch64-apple-ios-sim,\
+        x86_64-apple-ios,\
+        aarch64-apple-ios-macabi,\
+        x86_64-apple-ios-macabi,\
+        aarch64-apple-tvos,\
+        aarch64-apple-tvos-sim,\
+        aarch64-apple-visionos,\
+        aarch64-apple-visionos-sim,\
+        aarch64-apple-watchos,\
+        aarch64-apple-watchos-sim"
+      SCRIPT: ./x.py dist bootstrap --include-default-paths --host='' --target=$TARGETS
       # Mac Catalyst cannot currently compile the sanitizer:
       # https://github.com/rust-lang/rust/issues/129069
-      RUST_CONFIGURE_ARGS: --enable-sanitizers --enable-profiler --set rust.jemalloc --set target.aarch64-apple-ios-macabi.sanitizers=false --set target.x86_64-apple-ios-macabi.sanitizers=false
+      #
+      # And tvOS and watchOS don't currently support the profiler runtime:
+      # https://github.com/rust-lang/rust/issues/152426
+      RUST_CONFIGURE_ARGS: >-
+        --enable-sanitizers
+        --enable-profiler
+        --set rust.jemalloc
+        --set target.aarch64-apple-ios-macabi.sanitizers=false
+        --set target.x86_64-apple-ios-macabi.sanitizers=false
+        --set target.aarch64-apple-tvos.profiler=false
+        --set target.aarch64-apple-tvos-sim.profiler=false
+        --set target.aarch64-apple-watchos.profiler=false
+        --set target.aarch64-apple-watchos-sim.profiler=false
       # Ensure that host tooling is built to support our minimum support macOS version.
       # FIXME(madsmtm): This might be redundant, as we're not building host tooling here (?)
       MACOSX_DEPLOYMENT_TARGET: 10.12

src/doc/book

@@ -1 +1 @@
-Subproject commit 39aeceaa3aeab845bc4517e7a44e48727d3b9dbe
+Subproject commit 05d114287b7d6f6c9253d5242540f00fbd6172ab

src/doc/index.md

@@ -194,9 +194,8 @@ resources maintained by the [Embedded Working Group] useful.
 
 #### The Embedded Rust Book
 
-[The Embedded Rust Book] is targeted at developers familiar with embedded
-development and familiar with Rust, but have not used Rust for embedded
-development.
+[The Embedded Rust Book] is targeted at developers who are familiar with embedded
+development and Rust, but who have not used Rust for embedded development.
 
 [The Embedded Rust Book]: embedded-book/index.html
 [Rust project]: https://www.rust-lang.org

src/doc/nomicon

@@ -1 +1 @@
-Subproject commit 050c002a360fa45b701ea34feed7a860dc8a41bf
+Subproject commit b8f254a991b8b7e8f704527f0d4f343a4697dfa9

src/doc/not_found.md

@@ -41,7 +41,7 @@ Some things that might be helpful to you though:
     <input type="submit" value="Search" id="search-but">
     <!--
       Don't show the options by default,
-      since "From the Standary Library" doesn't work without JavaScript
+      since "From the Standard Library" doesn't work without JavaScript
     -->
     <fieldset id="search-from" style="display:none">
       <label><input name="from" value="library" type="radio"> From the Standard Library</label>

src/doc/reference

@@ -1 +1 @@
-Subproject commit 990819b86c22bbf538c0526f0287670f3dc1a67a
+Subproject commit addd0602c819b6526b9cc97653b0fadca395528c

src/doc/rustc/src/platform-support.md

@@ -148,6 +148,12 @@ target | std | notes
 [`aarch64-apple-ios`](platform-support/apple-ios.md) | ✓ | ARM64 iOS
 [`aarch64-apple-ios-macabi`](platform-support/apple-ios-macabi.md) | ✓ | Mac Catalyst on ARM64
 [`aarch64-apple-ios-sim`](platform-support/apple-ios.md) | ✓ | Apple iOS Simulator on ARM64
+[`aarch64-apple-tvos`](platform-support/apple-tvos.md) | ✓ | ARM64 tvOS
+[`aarch64-apple-tvos-sim`](platform-support/apple-tvos.md) | ✓ | ARM64 tvOS Simulator
+[`aarch64-apple-visionos`](platform-support/apple-visionos.md) | ✓ | ARM64 Apple visionOS
+[`aarch64-apple-visionos-sim`](platform-support/apple-visionos.md) | ✓ | ARM64 Apple visionOS Simulator
+[`aarch64-apple-watchos`](platform-support/apple-watchos.md) | ✓ | ARM64 Apple WatchOS
+[`aarch64-apple-watchos-sim`](platform-support/apple-watchos.md) | ✓ | ARM64 Apple WatchOS Simulator
 [`aarch64-linux-android`](platform-support/android.md) | ✓ | ARM64 Android
 [`aarch64-unknown-fuchsia`](platform-support/fuchsia.md) | ✓ | ARM64 Fuchsia
 [`aarch64-unknown-none`](platform-support/aarch64-unknown-none.md) | * | Bare ARM64, hardfloat
@@ -250,12 +256,6 @@ host tools.
 
 target | std | host | notes
 -------|:---:|:----:|-------
-[`aarch64-apple-tvos`](platform-support/apple-tvos.md) | ✓ |  | ARM64 tvOS
-[`aarch64-apple-tvos-sim`](platform-support/apple-tvos.md) | ✓ |  | ARM64 tvOS Simulator
-[`aarch64-apple-visionos`](platform-support/apple-visionos.md) | ✓ |  | ARM64 Apple visionOS
-[`aarch64-apple-visionos-sim`](platform-support/apple-visionos.md) | ✓ |  | ARM64 Apple visionOS Simulator
-[`aarch64-apple-watchos`](platform-support/apple-watchos.md) | ✓ |  | ARM64 Apple WatchOS
-[`aarch64-apple-watchos-sim`](platform-support/apple-watchos.md) | ✓ |  | ARM64 Apple WatchOS Simulator
 [`aarch64-kmc-solid_asp3`](platform-support/kmc-solid.md) | ✓ |  | ARM64 SOLID with TOPPERS/ASP3
 [`aarch64-nintendo-switch-freestanding`](platform-support/aarch64-nintendo-switch-freestanding.md) | * |  | ARM64 Nintendo Switch, Horizon
 [`aarch64-unknown-freebsd`](platform-support/freebsd.md) | ✓ | ✓ | ARM64 FreeBSD

src/doc/rustc/src/platform-support/apple-tvos.md

@@ -2,10 +2,13 @@
 
 Apple tvOS targets.
 
-**Tier: 3**
+**Tier: 2 (without Host Tools)**
 
 - `aarch64-apple-tvos`: Apple tvOS on ARM64.
 - `aarch64-apple-tvos-sim`: Apple tvOS Simulator on ARM64.
+
+**Tier: 3**
+
 - `x86_64-apple-tvos`: Apple tvOS Simulator on x86_64.
 
 ## Target maintainers
@@ -52,16 +55,13 @@ The following APIs are currently known to have missing or incomplete support:
 
 ## Building the target
 
-The targets can be built by enabling them for a `rustc` build in
-`bootstrap.toml`, by adding, for example:
-
-```toml
-[build]
-build-stage = 1
-target = ["aarch64-apple-tvos", "aarch64-apple-tvos-sim"]
+The tier 2 targets are distributed through `rustup`, and can be installed using one of:
+```console
+$ rustup target add aarch64-apple-tvos
+$ rustup target add aarch64-apple-tvos-sim
 ```
 
-Using the unstable `-Zbuild-std` with a nightly Cargo may also work.
+See [the instructions for iOS](./apple-ios.md#building-the-target) for how to build the tier 3 target.
 
 ## Building Rust programs
 

src/doc/rustc/src/platform-support/apple-visionos.md

@@ -2,7 +2,7 @@
 
 Apple visionOS / xrOS targets.
 
-**Tier: 3**
+**Tier: 2 (without Host Tools)**
 
 - `aarch64-apple-visionos`: Apple visionOS on arm64.
 - `aarch64-apple-visionos-sim`: Apple visionOS Simulator on arm64.
@@ -31,19 +31,12 @@ case `XROS_DEPLOYMENT_TARGET`.
 
 ## Building the target
 
-The targets can be built by enabling them for a `rustc` build in
-`bootstrap.toml`, by adding, for example:
-
-```toml
-[build]
-target = ["aarch64-apple-visionos", "aarch64-apple-visionos-sim"]
+The targets are distributed through `rustup`, and can be installed using one of:
+```console
+$ rustup target add aarch64-apple-visionos
+$ rustup target add aarch64-apple-visionos-sim
 ```
 
-Using the unstable `-Zbuild-std` with a nightly Cargo may also work.
-
-Note: Currently, a newer version of `libc` and `cc` may be required, this will
-be fixed in [#124560](https://github.com/rust-lang/rust/pull/124560).
-
 ## Building Rust programs
 
 See [the instructions for iOS](./apple-ios.md#building-rust-programs).

src/doc/rustc/src/platform-support/apple-watchos.md

@@ -2,10 +2,13 @@
 
 Apple watchOS targets.
 
-**Tier: 3**
+**Tier: 2 (without Host Tools)**
 
 - `aarch64-apple-watchos`: Apple WatchOS on ARM64.
 - `aarch64-apple-watchos-sim`: Apple WatchOS Simulator on ARM64.
+
+**Tier: 3**
+
 - `x86_64-apple-watchos-sim`: Apple WatchOS Simulator on 64-bit x86.
 - `arm64_32-apple-watchos`: Apple WatchOS on Arm 64_32.
 - `armv7k-apple-watchos`: Apple WatchOS on Armv7k.
@@ -37,16 +40,13 @@ case `WATCHOS_DEPLOYMENT_TARGET`.
 
 ## Building the target
 
-The targets can be built by enabling them for a `rustc` build in
-`bootstrap.toml`, by adding, for example:
-
-```toml
-[build]
-build-stage = 1
-target = ["aarch64-apple-watchos", "aarch64-apple-watchos-sim"]
+The tier 2 targets are distributed through `rustup`, and can be installed using one of:
+```console
+$ rustup target add aarch64-apple-watchos
+$ rustup target add aarch64-apple-watchos-sim
 ```
 
-Using the unstable `-Zbuild-std` with a nightly Cargo may also work.
+See [the instructions for iOS](./apple-ios.md#building-the-target) for how to build the tier 3 targets.
 
 ## Building Rust programs
 

tests/ui/attributes/const-stability-on-macro.rs

@@ -2,13 +2,13 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 #[rustc_const_stable(feature = "foo", since = "3.3.3")]
-//~^ ERROR macros cannot have const stability attributes
+//~^ ERROR attribute cannot be used on macro defs
 macro_rules! foo {
     () => {};
 }
 
-#[rustc_const_unstable(feature = "bar", issue="none")]
-//~^ ERROR macros cannot have const stability attributes
+#[rustc_const_unstable(feature = "bar", issue = "none")]
+//~^ ERROR attribute cannot be used on macro defs
 macro_rules! bar {
     () => {};
 }

tests/ui/attributes/const-stability-on-macro.stderr

@@ -1,20 +1,18 @@
-error: macros cannot have const stability attributes
+error: `#[rustc_const_stable]` attribute cannot be used on macro defs
   --> $DIR/const-stability-on-macro.rs:4:1
    |
 LL | #[rustc_const_stable(feature = "foo", since = "3.3.3")]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid const stability attribute
-LL |
-LL | macro_rules! foo {
-   | ---------------- const stability attribute affects this macro
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: `#[rustc_const_stable]` can be applied to associated consts, constants, crates, functions, impl blocks, statics, traits, and use statements
 
-error: macros cannot have const stability attributes
+error: `#[rustc_const_unstable]` attribute cannot be used on macro defs
   --> $DIR/const-stability-on-macro.rs:10:1
    |
-LL | #[rustc_const_unstable(feature = "bar", issue="none")]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid const stability attribute
-LL |
-LL | macro_rules! bar {
-   | ---------------- const stability attribute affects this macro
+LL | #[rustc_const_unstable(feature = "bar", issue = "none")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: `#[rustc_const_unstable]` can be applied to associated consts, constants, crates, functions, impl blocks, statics, traits, and use statements
 
 error: aborting due to 2 previous errors
 

tests/ui/const-generics/associated-const-bindings/dyn-compat-const-projection-behind-trait-alias-mentions-self.rs

@@ -15,6 +15,7 @@ trait Trait {
 struct Hold<T: ?Sized>(T);
 
 trait Bound = Trait<Y = { Hold::<Self> }>;
+//~^ ERROR the constant `Hold::<Self>` is not of type `i32`
 
 fn main() {
     let _: dyn Bound; //~ ERROR associated constant binding in trait object type mentions `Self`

tests/ui/const-generics/associated-const-bindings/dyn-compat-const-projection-behind-trait-alias-mentions-self.stderr

@@ -1,5 +1,17 @@
+error: the constant `Hold::<Self>` is not of type `i32`
+  --> $DIR/dyn-compat-const-projection-behind-trait-alias-mentions-self.rs:17:21
+   |
+LL | trait Bound = Trait<Y = { Hold::<Self> }>;
+   |                     ^^^^^^^^^^^^^^^^^^^^ expected `i32`, found struct constructor
+   |
+note: required by a const generic parameter in `Bound`
+  --> $DIR/dyn-compat-const-projection-behind-trait-alias-mentions-self.rs:17:21
+   |
+LL | trait Bound = Trait<Y = { Hold::<Self> }>;
+   |                     ^^^^^^^^^^^^^^^^^^^^ required by this const generic parameter in `Bound`
+
 error: associated constant binding in trait object type mentions `Self`
-  --> $DIR/dyn-compat-const-projection-behind-trait-alias-mentions-self.rs:20:12
+  --> $DIR/dyn-compat-const-projection-behind-trait-alias-mentions-self.rs:21:12
    |
 LL | trait Bound = Trait<Y = { Hold::<Self> }>;
    |                     -------------------- this binding mentions `Self`
@@ -7,5 +19,5 @@ LL | trait Bound = Trait<Y = { Hold::<Self> }>;
 LL |     let _: dyn Bound;
    |            ^^^^^^^^^ contains a mention of `Self`
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 

tests/ui/const-generics/associated-const-bindings/dyn-const-projection-escaping-bound-vars.rs

@@ -0,0 +1,11 @@
+//! Check associated const binding with escaping bound vars doesn't cause ICE
+//! (#151642)
+//@ check-pass
+
+#![feature(min_generic_const_args)]
+#![expect(incomplete_features)]
+
+trait Trait2<'a> { type const ASSOC: i32; }
+fn g(_: for<'a> fn(Box<dyn Trait2<'a, ASSOC = 10>>)) {}
+
+fn main() {}

tests/ui/const-generics/associated-const-bindings/wf-mismatch-1.rs

@@ -0,0 +1,11 @@
+//! Check that we correctly handle associated const bindings
+//! in `impl Trait` where the RHS is a const param (#151642).
+
+#![feature(min_generic_const_args)]
+#![expect(incomplete_features)]
+
+trait Trait { type const CT: bool; }
+
+fn f<const N: i32>(_: impl Trait<CT = { N }>) {}
+//~^ ERROR the constant `N` is not of type `bool`
+fn main() {}

tests/ui/const-generics/associated-const-bindings/wf-mismatch-1.stderr

@@ -0,0 +1,14 @@
+error: the constant `N` is not of type `bool`
+  --> $DIR/wf-mismatch-1.rs:9:34
+   |
+LL | fn f<const N: i32>(_: impl Trait<CT = { N }>) {}
+   |                                  ^^^^^^^^^^ expected `bool`, found `i32`
+   |
+note: required by a const generic parameter in `f`
+  --> $DIR/wf-mismatch-1.rs:9:34
+   |
+LL | fn f<const N: i32>(_: impl Trait<CT = { N }>) {}
+   |                                  ^^^^^^^^^^ required by this const generic parameter in `f`
+
+error: aborting due to 1 previous error
+

tests/ui/const-generics/associated-const-bindings/wf-mismatch-2.rs

@@ -0,0 +1,13 @@
+//! Check that we correctly handle associated const bindings
+//! in `dyn Trait` where the RHS is a const param (#151642).
+
+#![feature(min_generic_const_args)]
+#![expect(incomplete_features)]
+
+trait Trait { type const CT: bool; }
+
+fn f<const N: i32>() {
+    let _: dyn Trait<CT = { N }>;
+    //~^ ERROR the constant `N` is not of type `bool`
+}
+fn main() {}

tests/ui/const-generics/associated-const-bindings/wf-mismatch-2.stderr

@@ -0,0 +1,8 @@
+error: the constant `N` is not of type `bool`
+  --> $DIR/wf-mismatch-2.rs:10:12
+   |
+LL |     let _: dyn Trait<CT = { N }>;
+   |            ^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `i32`
+
+error: aborting due to 1 previous error
+

tests/ui/const-generics/associated-const-bindings/wf-mismatch-3.rs

@@ -0,0 +1,17 @@
+//! Check that we correctly handle associated const bindings
+//! where the RHS is a normalizable const projection (#151642).
+
+#![feature(min_generic_const_args)]
+#![expect(incomplete_features)]
+
+trait Trait { type const CT: bool; }
+
+trait Bound { type const N: u32; }
+impl Bound for () { type const N: u32 = 0; }
+
+fn f() { let _: dyn Trait<CT = { <() as Bound>::N }>; }
+//~^ ERROR the constant `0` is not of type `bool`
+fn g(_: impl Trait<CT = { <() as Bound>::N }>) {}
+//~^ ERROR the constant `0` is not of type `bool`
+
+fn main() {}

tests/ui/const-generics/associated-const-bindings/wf-mismatch-3.stderr

@@ -0,0 +1,20 @@
+error: the constant `0` is not of type `bool`
+  --> $DIR/wf-mismatch-3.rs:14:20
+   |
+LL | fn g(_: impl Trait<CT = { <() as Bound>::N }>) {}
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `u32`
+   |
+note: required by a const generic parameter in `g`
+  --> $DIR/wf-mismatch-3.rs:14:20
+   |
+LL | fn g(_: impl Trait<CT = { <() as Bound>::N }>) {}
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this const generic parameter in `g`
+
+error: the constant `0` is not of type `bool`
+  --> $DIR/wf-mismatch-3.rs:12:17
+   |
+LL | fn f() { let _: dyn Trait<CT = { <() as Bound>::N }>; }
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `u32`
+
+error: aborting due to 2 previous errors
+

tests/ui/generic-const-items/assoc-const-bindings.rs

@@ -1,35 +1,33 @@
 //@ check-pass
 
 #![feature(generic_const_items, min_generic_const_args)]
-#![feature(adt_const_params)]
-#![allow(incomplete_features)]
+#![feature(adt_const_params, unsized_const_params, generic_const_parameter_types)]
+#![expect(incomplete_features)]
+
+use std::marker::{ConstParamTy, ConstParamTy_};
 
 trait Owner {
     type const C<const N: u32>: u32;
     type const K<const N: u32>: u32;
-    // #[type_const]
-    // const Q<T>: Maybe<T>;
+    type const Q<T: ConstParamTy_>: Maybe<T>;
 }
 
 impl Owner for () {
     type const C<const N: u32>: u32 = N;
     type const K<const N: u32>: u32 = const { 99 + 1 };
-    // FIXME(mgca): re-enable once we properly support ctors and generics on paths
-    // #[type_const]
-    // const Q<T>: Maybe<T> = Maybe::Nothing;
+    type const Q<T: ConstParamTy_>: Maybe<T> = Maybe::Nothing::<T>;
 }
 
 fn take0<const N: u32>(_: impl Owner<C<N> = { N }>) {}
 fn take1(_: impl Owner<K<99> = 100>) {}
-// FIXME(mgca): re-enable once we properly support ctors and generics on paths
-// fn take2(_: impl Owner<Q<()> = { Maybe::Just(()) }>) {}
+fn take2(_: impl Owner<Q<()> = { Maybe::Just::<()>(()) }>) {}
 
 fn main() {
     take0::<128>(());
     take1(());
 }
 
-#[derive(PartialEq, Eq, std::marker::ConstParamTy)]
+#[derive(PartialEq, Eq, ConstParamTy)]
 enum Maybe<T> {
     Nothing,
     Just(T),