Rollup of 10 pull requests

compiler/rustc_borrowck/src/type_check/opaque_types.rs

@@ -25,8 +25,8 @@ pub(super) fn take_opaques_and_register_member_constraints<'tcx>(
     let opaque_types = infcx
         .take_opaque_types()
         .into_iter()
-        .map(|(opaque_type_key, decl)| {
-            let hidden_type = infcx.resolve_vars_if_possible(decl.hidden_type);
+        .map(|(opaque_type_key, hidden_type)| {
+            let hidden_type = infcx.resolve_vars_if_possible(hidden_type);
             register_member_constraints(
                 typeck,
                 &mut member_constraints,

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -2451,10 +2451,10 @@ fn add_order_independent_options(
     }
 
     if sess.target.os == "emscripten" {
-        cmd.cc_arg(if sess.panic_strategy() == PanicStrategy::Abort {
-            "-sDISABLE_EXCEPTION_CATCHING=1"
-        } else if sess.opts.unstable_opts.emscripten_wasm_eh {
+        cmd.cc_arg(if sess.opts.unstable_opts.emscripten_wasm_eh {
             "-fwasm-exceptions"
+        } else if sess.panic_strategy() == PanicStrategy::Abort {
+            "-sDISABLE_EXCEPTION_CATCHING=1"
         } else {
             "-sDISABLE_EXCEPTION_CATCHING=0"
         });

compiler/rustc_hir_analysis/src/check/check.rs

@@ -436,9 +436,9 @@ fn check_opaque_meets_bounds<'tcx>(
     } else {
         // Check that any hidden types found during wf checking match the hidden types that `type_of` sees.
         for (mut key, mut ty) in infcx.take_opaque_types() {
-            ty.hidden_type.ty = infcx.resolve_vars_if_possible(ty.hidden_type.ty);
+            ty.ty = infcx.resolve_vars_if_possible(ty.ty);
             key = infcx.resolve_vars_if_possible(key);
-            sanity_check_found_hidden_type(tcx, key, ty.hidden_type)?;
+            sanity_check_found_hidden_type(tcx, key, ty)?;
         }
         Ok(())
     }
@@ -1873,7 +1873,7 @@ pub(super) fn check_coroutine_obligations(
         // Check that any hidden types found when checking these stalled coroutine obligations
         // are valid.
         for (key, ty) in infcx.take_opaque_types() {
-            let hidden_type = infcx.resolve_vars_if_possible(ty.hidden_type);
+            let hidden_type = infcx.resolve_vars_if_possible(ty);
             let key = infcx.resolve_vars_if_possible(key);
             sanity_check_found_hidden_type(tcx, key, hidden_type)?;
         }

compiler/rustc_hir_typeck/src/demand.rs

@@ -85,6 +85,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         self.annotate_expected_due_to_let_ty(err, expr, error);
         self.annotate_loop_expected_due_to_inference(err, expr, error);
+        if self.annotate_mut_binding_to_immutable_binding(err, expr, error) {
+            return;
+        }
 
         // FIXME(#73154): For now, we do leak check when coercing function
         // pointers in typeck, instead of only during borrowck. This can lead
@@ -795,6 +798,98 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    /// Detect the following case
+    ///
+    /// ```text
+    /// fn change_object(mut a: &Ty) {
+    ///     let a = Ty::new();
+    ///     b = a;
+    /// }
+    /// ```
+    ///
+    /// where the user likely meant to modify the value behind there reference, use `a` as an out
+    /// parameter, instead of mutating the local binding. When encountering this we suggest:
+    ///
+    /// ```text
+    /// fn change_object(a: &'_ mut Ty) {
+    ///     let a = Ty::new();
+    ///     *b = a;
+    /// }
+    /// ```
+    fn annotate_mut_binding_to_immutable_binding(
+        &self,
+        err: &mut Diag<'_>,
+        expr: &hir::Expr<'_>,
+        error: Option<TypeError<'tcx>>,
+    ) -> bool {
+        if let Some(TypeError::Sorts(ExpectedFound { expected, found })) = error
+            && let ty::Ref(_, inner, hir::Mutability::Not) = expected.kind()
+
+            // The difference between the expected and found values is one level of borrowing.
+            && self.can_eq(self.param_env, *inner, found)
+
+            // We have an `ident = expr;` assignment.
+            && let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Assign(lhs, rhs, _), .. }) =
+                self.tcx.parent_hir_node(expr.hir_id)
+            && rhs.hir_id == expr.hir_id
+
+            // We are assigning to some binding.
+            && let hir::ExprKind::Path(hir::QPath::Resolved(
+                None,
+                hir::Path { res: hir::def::Res::Local(hir_id), .. },
+            )) = lhs.kind
+            && let hir::Node::Pat(pat) = self.tcx.hir_node(*hir_id)
+
+            // The pattern we have is an fn argument.
+            && let hir::Node::Param(hir::Param { ty_span, .. }) =
+                self.tcx.parent_hir_node(pat.hir_id)
+            && let item = self.tcx.hir().get_parent_item(pat.hir_id)
+            && let item = self.tcx.hir_owner_node(item)
+            && let Some(fn_decl) = item.fn_decl()
+
+            // We have a mutable binding in the argument.
+            && let hir::PatKind::Binding(hir::BindingMode::MUT, _hir_id, ident, _) = pat.kind
+
+            // Look for the type corresponding to the argument pattern we have in the argument list.
+            && let Some(ty_sugg) = fn_decl
+                .inputs
+                .iter()
+                .filter_map(|ty| {
+                    if ty.span == *ty_span
+                        && let hir::TyKind::Ref(lt, x) = ty.kind
+                    {
+                        // `&'name Ty` -> `&'name mut Ty` or `&Ty` -> `&mut Ty`
+                        Some((
+                            x.ty.span.shrink_to_lo(),
+                            format!(
+                                "{}mut ",
+                                if lt.ident.span.lo() == lt.ident.span.hi() { "" } else { " " }
+                            ),
+                        ))
+                    } else {
+                        None
+                    }
+                })
+                .next()
+        {
+            let sugg = vec![
+                ty_sugg,
+                (pat.span.until(ident.span), String::new()),
+                (lhs.span.shrink_to_lo(), "*".to_string()),
+            ];
+            // We suggest changing the argument from `mut ident: &Ty` to `ident: &'_ mut Ty` and the
+            // assignment from `ident = val;` to `*ident = val;`.
+            err.multipart_suggestion_verbose(
+                "you might have meant to mutate the pointed at value being passed in, instead of \
+                changing the reference in the local binding",
+                sugg,
+                Applicability::MaybeIncorrect,
+            );
+            return true;
+        }
+        false
+    }
+
     fn annotate_alternative_method_deref(
         &self,
         err: &mut Diag<'_>,

compiler/rustc_hir_typeck/src/writeback.rs

@@ -562,9 +562,9 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
         // types or by using this function at the end of writeback and running it as a
         // fixpoint.
         let opaque_types = self.fcx.infcx.clone_opaque_types();
-        for (opaque_type_key, decl) in opaque_types {
-            let hidden_type = self.resolve(decl.hidden_type, &decl.hidden_type.span);
-            let opaque_type_key = self.resolve(opaque_type_key, &decl.hidden_type.span);
+        for (opaque_type_key, hidden_type) in opaque_types {
+            let hidden_type = self.resolve(hidden_type, &hidden_type.span);
+            let opaque_type_key = self.resolve(opaque_type_key, &hidden_type.span);
 
             if !self.fcx.next_trait_solver() {
                 if let ty::Alias(ty::Opaque, alias_ty) = hidden_type.ty.kind()

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

@@ -155,12 +155,12 @@ impl<'tcx> InferCtxt<'tcx> {
             .opaque_type_storage
             .opaque_types
             .iter()
-            .map(|(k, v)| (*k, v.hidden_type.ty))
+            .map(|(k, v)| (*k, v.ty))
             .collect()
     }
 
     fn take_opaque_types_for_query_response(&self) -> Vec<(ty::OpaqueTypeKey<'tcx>, Ty<'tcx>)> {
-        self.take_opaque_types().into_iter().map(|(k, v)| (k, v.hidden_type.ty)).collect()
+        self.take_opaque_types().into_iter().map(|(k, v)| (k, v.ty)).collect()
     }
 
     /// Given the (canonicalized) result to a canonical query,

compiler/rustc_infer/src/infer/mod.rs

@@ -234,7 +234,7 @@ impl<'tcx> InferCtxtInner<'tcx> {
     pub fn iter_opaque_types(
         &self,
     ) -> impl Iterator<Item = (ty::OpaqueTypeKey<'tcx>, ty::OpaqueHiddenType<'tcx>)> + '_ {
-        self.opaque_type_storage.opaque_types.iter().map(|(&k, v)| (k, v.hidden_type))
+        self.opaque_type_storage.opaque_types.iter().map(|(&k, &v)| (k, v))
     }
 }
 

compiler/rustc_infer/src/infer/opaque_types/mod.rs

@@ -19,20 +19,9 @@ use crate::traits::{self, Obligation, PredicateObligations};
 
 mod table;
 
-pub(crate) type OpaqueTypeMap<'tcx> = FxIndexMap<OpaqueTypeKey<'tcx>, OpaqueTypeDecl<'tcx>>;
+pub(crate) type OpaqueTypeMap<'tcx> = FxIndexMap<OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>>;
 pub(crate) use table::{OpaqueTypeStorage, OpaqueTypeTable};
 
-/// Information about the opaque types whose values we
-/// are inferring in this function (these are the `impl Trait` that
-/// appear in the return type).
-#[derive(Clone, Debug)]
-pub struct OpaqueTypeDecl<'tcx> {
-    /// The hidden types that have been inferred for this opaque type.
-    /// There can be multiple, but they are all `lub`ed together at the end
-    /// to obtain the canonical hidden type.
-    pub hidden_type: OpaqueHiddenType<'tcx>,
-}
-
 impl<'tcx> InferCtxt<'tcx> {
     /// This is a backwards compatibility hack to prevent breaking changes from
     /// lazy TAIT around RPIT handling.

compiler/rustc_infer/src/infer/opaque_types/table.rs

@@ -3,23 +3,27 @@ use rustc_middle::bug;
 use rustc_middle::ty::{self, OpaqueHiddenType, OpaqueTypeKey, Ty};
 use tracing::instrument;
 
-use super::{OpaqueTypeDecl, OpaqueTypeMap};
+use super::OpaqueTypeMap;
 use crate::infer::snapshot::undo_log::{InferCtxtUndoLogs, UndoLog};
 
 #[derive(Default, Debug, Clone)]
 pub(crate) struct OpaqueTypeStorage<'tcx> {
     /// Opaque types found in explicit return types and their
     /// associated fresh inference variable. Writeback resolves these
     /// variables to get the concrete type, which can be used to
-    /// 'de-opaque' OpaqueTypeDecl, after typeck is done with all functions.
+    /// 'de-opaque' OpaqueHiddenType, after typeck is done with all functions.
     pub opaque_types: OpaqueTypeMap<'tcx>,
 }
 
 impl<'tcx> OpaqueTypeStorage<'tcx> {
     #[instrument(level = "debug")]
-    pub(crate) fn remove(&mut self, key: OpaqueTypeKey<'tcx>, idx: Option<OpaqueHiddenType<'tcx>>) {
-        if let Some(idx) = idx {
-            self.opaque_types.get_mut(&key).unwrap().hidden_type = idx;
+    pub(crate) fn remove(
+        &mut self,
+        key: OpaqueTypeKey<'tcx>,
+        prev: Option<OpaqueHiddenType<'tcx>>,
+    ) {
+        if let Some(prev) = prev {
+            *self.opaque_types.get_mut(&key).unwrap() = prev;
         } else {
             // FIXME(#120456) - is `swap_remove` correct?
             match self.opaque_types.swap_remove(&key) {
@@ -59,13 +63,12 @@ impl<'a, 'tcx> OpaqueTypeTable<'a, 'tcx> {
         key: OpaqueTypeKey<'tcx>,
         hidden_type: OpaqueHiddenType<'tcx>,
     ) -> Option<Ty<'tcx>> {
-        if let Some(decl) = self.storage.opaque_types.get_mut(&key) {
-            let prev = std::mem::replace(&mut decl.hidden_type, hidden_type);
+        if let Some(entry) = self.storage.opaque_types.get_mut(&key) {
+            let prev = std::mem::replace(entry, hidden_type);
             self.undo_log.push(UndoLog::OpaqueTypes(key, Some(prev)));
             return Some(prev.ty);
         }
-        let decl = OpaqueTypeDecl { hidden_type };
-        self.storage.opaque_types.insert(key, decl);
+        self.storage.opaque_types.insert(key, hidden_type);
         self.undo_log.push(UndoLog::OpaqueTypes(key, None));
         None
     }

compiler/rustc_lint/src/impl_trait_overcaptures.rs

@@ -99,7 +99,7 @@ declare_lint! {
     /// To fix this, remove the `use<'a>`, since the lifetime is already captured
     /// since it is in scope.
     pub IMPL_TRAIT_REDUNDANT_CAPTURES,
-    Warn,
+    Allow,
     "redundant precise-capturing `use<...>` syntax on an `impl Trait`",
 }
 

compiler/rustc_middle/src/mir/pretty.rs

@@ -1555,16 +1555,22 @@ pub fn write_allocations<'tcx>(
                 write!(w, " (vtable: impl {dyn_ty} for {ty})")?
             }
             Some(GlobalAlloc::Static(did)) if !tcx.is_foreign_item(did) => {
-                match tcx.eval_static_initializer(did) {
-                    Ok(alloc) => {
-                        write!(w, " (static: {}, ", tcx.def_path_str(did))?;
-                        write_allocation_track_relocs(w, alloc)?;
+                write!(w, " (static: {}", tcx.def_path_str(did))?;
+                if body.phase <= MirPhase::Runtime(RuntimePhase::PostCleanup)
+                    && tcx.hir().body_const_context(body.source.def_id()).is_some()
+                {
+                    // Statics may be cyclic and evaluating them too early
+                    // in the MIR pipeline may cause cycle errors even though
+                    // normal compilation is fine.
+                    write!(w, ")")?;
+                } else {
+                    match tcx.eval_static_initializer(did) {
+                        Ok(alloc) => {
+                            write!(w, ", ")?;
+                            write_allocation_track_relocs(w, alloc)?;
+                        }
+                        Err(_) => write!(w, ", error during initializer evaluation)")?,
                     }
-                    Err(_) => write!(
-                        w,
-                        " (static: {}, error during initializer evaluation)",
-                        tcx.def_path_str(did)
-                    )?,
                 }
             }
             Some(GlobalAlloc::Static(did)) => {

compiler/rustc_passes/messages.ftl

@@ -799,6 +799,9 @@ passes_unused_assign = value assigned to `{$name}` is never read
 passes_unused_assign_passed = value passed to `{$name}` is never read
     .help = maybe it is overwritten before being read?
 
+passes_unused_assign_suggestion =
+    you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding
+
 passes_unused_capture_maybe_capture_ref = value captured by `{$name}` is never read
     .help = did you mean to capture by reference instead?
 

compiler/rustc_passes/src/errors.rs

@@ -1787,9 +1787,26 @@ pub(crate) struct IneffectiveUnstableImpl;
 
 #[derive(LintDiagnostic)]
 #[diag(passes_unused_assign)]
-#[help]
 pub(crate) struct UnusedAssign {
     pub name: String,
+    #[subdiagnostic]
+    pub suggestion: Option<UnusedAssignSuggestion>,
+    #[help]
+    pub help: bool,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(passes_unused_assign_suggestion, applicability = "maybe-incorrect")]
+pub(crate) struct UnusedAssignSuggestion {
+    pub pre: &'static str,
+    #[suggestion_part(code = "{pre}mut ")]
+    pub ty_span: Span,
+    #[suggestion_part(code = "")]
+    pub ty_ref_span: Span,
+    #[suggestion_part(code = "*")]
+    pub ident_span: Span,
+    #[suggestion_part(code = "")]
+    pub expr_ref_span: Span,
 }
 
 #[derive(LintDiagnostic)]

compiler/rustc_passes/src/liveness.rs

@@ -1360,7 +1360,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Liveness<'a, 'tcx> {
     fn visit_local(&mut self, local: &'tcx hir::LetStmt<'tcx>) {
         self.check_unused_vars_in_pat(local.pat, None, None, |spans, hir_id, ln, var| {
             if local.init.is_some() {
-                self.warn_about_dead_assign(spans, hir_id, ln, var);
+                self.warn_about_dead_assign(spans, hir_id, ln, var, None);
             }
         });
 
@@ -1460,7 +1460,8 @@ impl<'tcx> Liveness<'_, 'tcx> {
                     // as being used.
                     let ln = self.live_node(expr.hir_id, expr.span);
                     let var = self.variable(var_hid, expr.span);
-                    self.warn_about_dead_assign(vec![expr.span], expr.hir_id, ln, var);
+                    let sugg = self.annotate_mut_binding_to_immutable_binding(var_hid, expr);
+                    self.warn_about_dead_assign(vec![expr.span], expr.hir_id, ln, var, sugg);
                 }
             }
             _ => {
@@ -1585,6 +1586,70 @@ impl<'tcx> Liveness<'_, 'tcx> {
         }
     }
 
+    /// Detect the following case
+    ///
+    /// ```text
+    /// fn change_object(mut a: &Ty) {
+    ///     let a = Ty::new();
+    ///     b = &a;
+    /// }
+    /// ```
+    ///
+    /// where the user likely meant to modify the value behind there reference, use `a` as an out
+    /// parameter, instead of mutating the local binding. When encountering this we suggest:
+    ///
+    /// ```text
+    /// fn change_object(a: &'_ mut Ty) {
+    ///     let a = Ty::new();
+    ///     *b = a;
+    /// }
+    /// ```
+    fn annotate_mut_binding_to_immutable_binding(
+        &self,
+        var_hid: HirId,
+        expr: &'tcx Expr<'tcx>,
+    ) -> Option<errors::UnusedAssignSuggestion> {
+        if let hir::Node::Expr(parent) = self.ir.tcx.parent_hir_node(expr.hir_id)
+            && let hir::ExprKind::Assign(_, rhs, _) = parent.kind
+            && let hir::ExprKind::AddrOf(borrow_kind, _mut, inner) = rhs.kind
+            && let hir::BorrowKind::Ref = borrow_kind
+            && let hir::Node::Pat(pat) = self.ir.tcx.hir_node(var_hid)
+            && let hir::Node::Param(hir::Param { ty_span, .. }) =
+                self.ir.tcx.parent_hir_node(pat.hir_id)
+            && let item_id = self.ir.tcx.hir().get_parent_item(pat.hir_id)
+            && let item = self.ir.tcx.hir_owner_node(item_id)
+            && let Some(fn_decl) = item.fn_decl()
+            && let hir::PatKind::Binding(hir::BindingMode::MUT, _hir_id, ident, _) = pat.kind
+            && let Some((ty_span, pre)) = fn_decl
+                .inputs
+                .iter()
+                .filter_map(|ty| {
+                    if ty.span == *ty_span
+                        && let hir::TyKind::Ref(lt, mut_ty) = ty.kind
+                    {
+                        // `&'name Ty` -> `&'name mut Ty` or `&Ty` -> `&mut Ty`
+                        Some((
+                            mut_ty.ty.span.shrink_to_lo(),
+                            if lt.ident.span.lo() == lt.ident.span.hi() { "" } else { " " },
+                        ))
+                    } else {
+                        None
+                    }
+                })
+                .next()
+        {
+            Some(errors::UnusedAssignSuggestion {
+                ty_span,
+                pre,
+                ty_ref_span: pat.span.until(ident.span),
+                ident_span: expr.span.shrink_to_lo(),
+                expr_ref_span: rhs.span.until(inner.span),
+            })
+        } else {
+            None
+        }
+    }
+
     #[instrument(skip(self), level = "INFO")]
     fn report_unused(
         &self,
@@ -1738,15 +1803,23 @@ impl<'tcx> Liveness<'_, 'tcx> {
         suggs
     }
 
-    fn warn_about_dead_assign(&self, spans: Vec<Span>, hir_id: HirId, ln: LiveNode, var: Variable) {
+    fn warn_about_dead_assign(
+        &self,
+        spans: Vec<Span>,
+        hir_id: HirId,
+        ln: LiveNode,
+        var: Variable,
+        suggestion: Option<errors::UnusedAssignSuggestion>,
+    ) {
         if !self.live_on_exit(ln, var)
             && let Some(name) = self.should_warn(var)
         {
+            let help = suggestion.is_none();
             self.ir.tcx.emit_node_span_lint(
                 lint::builtin::UNUSED_ASSIGNMENTS,
                 hir_id,
                 spans,
-                errors::UnusedAssign { name },
+                errors::UnusedAssign { name, suggestion, help },
             );
         }
     }

library/std/src/sys/pal/uefi/helpers.rs

@@ -222,14 +222,14 @@ pub(crate) fn runtime_services() -> Option<NonNull<r_efi::efi::RuntimeServices>>
     NonNull::new(runtime_services)
 }
 
-pub(crate) struct DevicePath(NonNull<r_efi::protocols::device_path::Protocol>);
+pub(crate) struct OwnedDevicePath(NonNull<r_efi::protocols::device_path::Protocol>);
 
-impl DevicePath {
+impl OwnedDevicePath {
     pub(crate) fn from_text(p: &OsStr) -> io::Result<Self> {
         fn inner(
             p: &OsStr,
             protocol: NonNull<r_efi::protocols::device_path_from_text::Protocol>,
-        ) -> io::Result<DevicePath> {
+        ) -> io::Result<OwnedDevicePath> {
             let path_vec = p.encode_wide().chain(Some(0)).collect::<Vec<u16>>();
             if path_vec[..path_vec.len() - 1].contains(&0) {
                 return Err(const_error!(
@@ -242,7 +242,7 @@ impl DevicePath {
                 unsafe { ((*protocol.as_ptr()).convert_text_to_device_path)(path_vec.as_ptr()) };
 
             NonNull::new(path)
-                .map(DevicePath)
+                .map(OwnedDevicePath)
                 .ok_or_else(|| const_error!(io::ErrorKind::InvalidFilename, "Invalid Device Path"))
         }
 
@@ -275,12 +275,12 @@ impl DevicePath {
         ))
     }
 
-    pub(crate) fn as_ptr(&self) -> *mut r_efi::protocols::device_path::Protocol {
+    pub(crate) const fn as_ptr(&self) -> *mut r_efi::protocols::device_path::Protocol {
         self.0.as_ptr()
     }
 }
 
-impl Drop for DevicePath {
+impl Drop for OwnedDevicePath {
     fn drop(&mut self) {
         if let Some(bt) = boot_services() {
             let bt: NonNull<r_efi::efi::BootServices> = bt.cast();
@@ -291,6 +291,15 @@ impl Drop for DevicePath {
     }
 }
 
+impl crate::fmt::Debug for OwnedDevicePath {
+    fn fmt(&self, f: &mut crate::fmt::Formatter<'_>) -> crate::fmt::Result {
+        match device_path_to_text(self.0) {
+            Ok(p) => p.fmt(f),
+            Err(_) => f.debug_struct("OwnedDevicePath").finish_non_exhaustive(),
+        }
+    }
+}
+
 pub(crate) struct OwnedProtocol<T> {
     guid: r_efi::efi::Guid,
     handle: NonNull<crate::ffi::c_void>,

library/std/src/sys/pal/uefi/process.rs

@@ -326,7 +326,7 @@ mod uefi_command_internal {
 
     impl Image {
         pub fn load_image(p: &OsStr) -> io::Result<Self> {
-            let path = helpers::DevicePath::from_text(p)?;
+            let path = helpers::OwnedDevicePath::from_text(p)?;
             let boot_services: NonNull<r_efi::efi::BootServices> = boot_services()
                 .ok_or_else(|| const_error!(io::ErrorKind::NotFound, "Boot Services not found"))?
                 .cast();

src/bootstrap/Cargo.toml

@@ -65,7 +65,7 @@ xz2 = "0.1"
 # Dependencies needed by the build-metrics feature
 sysinfo = { version = "0.33.0", default-features = false, optional = true, features = ["system"] }
 
-# Dependencies needed by the `logging` feature
+# Dependencies needed by the `tracing` feature
 tracing = { version = "0.1", optional = true, features = ["attributes"] }
 tracing-subscriber = { version = "0.3", optional = true, features = ["env-filter", "fmt", "registry", "std"] }
 tracing-tree = { version = "0.4.0", optional = true }

src/bootstrap/src/core/build_steps/tool.rs

@@ -334,7 +334,11 @@ macro_rules! bootstrap_tool {
 }
 
 bootstrap_tool!(
-    Rustbook, "src/tools/rustbook", "rustbook", submodules = SUBMODULES_FOR_RUSTBOOK;
+    // This is marked as an external tool because it includes dependencies
+    // from submodules. Trying to keep the lints in sync between all the repos
+    // is a bit of a pain. Unfortunately it means the rustbook source itself
+    // doesn't deny warnings, but it is a relatively small piece of code.
+    Rustbook, "src/tools/rustbook", "rustbook", is_external_tool = true, submodules = SUBMODULES_FOR_RUSTBOOK;
     UnstableBookGen, "src/tools/unstable-book-gen", "unstable-book-gen";
     Tidy, "src/tools/tidy", "tidy";
     Linkchecker, "src/tools/linkchecker", "linkchecker";

tests/assembly/simd-intrinsic-gather.rs

@@ -38,6 +38,6 @@ pub unsafe extern "C" fn gather_f64x4(mask: m64x4, ptrs: pf64x4) -> f64x4 {
     // x86-avx512: vpsllq ymm0, ymm0, 63
     // x86-avx512-NEXT: vpmovq2m k1, ymm0
     // x86-avx512-NEXT: vpxor xmm0, xmm0, xmm0
-    // x86-avx512-NEXT: vgatherqpd ymm0 {k1}, ymmword ptr [1*ymm1]
+    // x86-avx512-NEXT: vgatherqpd ymm0 {k1}, {{(ymmword)|(qword)}} ptr [1*ymm1]
     simd_gather(f64x4([0_f64, 0_f64, 0_f64, 0_f64]), ptrs, mask)
 }

tests/assembly/simd-intrinsic-scatter.rs

@@ -34,6 +34,6 @@ extern "rust-intrinsic" {
 pub unsafe extern "C" fn scatter_f64x4(values: f64x4, ptrs: pf64x4, mask: m64x4) {
     // x86-avx512: vpsllq ymm2, ymm2, 63
     // x86-avx512-NEXT: vpmovq2m k1, ymm2
-    // x86-avx512-NEXT: vscatterqpd ymmword ptr [1*ymm1] {k1}, ymm0
+    // x86-avx512-NEXT: vscatterqpd {{(ymmword)|(qword)}} ptr [1*ymm1] {k1}, ymm0
     simd_scatter(values, ptrs, mask)
 }

tests/mir-opt/building/dump_mir_cycle.rs

@@ -0,0 +1,19 @@
+#[derive(Debug)]
+pub struct Thing {
+    pub next: &'static Thing,
+}
+
+pub static THING: Thing = Thing { next: &THING };
+// CHECK: alloc{{.+}} (static: THING)
+
+const fn thing() -> &'static Thing {
+    &MUTUALLY_RECURSIVE
+}
+
+pub static MUTUALLY_RECURSIVE: Thing = Thing { next: thing() };
+// CHECK: alloc{{.+}} (static: MUTUALLY_RECURSIVE)
+
+fn main() {
+    // Generate optimized MIR for the const fn, too.
+    thing();
+}

tests/mir-opt/const_promotion_extern_static.BAR-promoted[0].SimplifyCfg-pre-optimizations.after.mir

@@ -15,6 +15,4 @@ const BAR::promoted[0]: &[&i32; 1] = {
     }
 }
 
-ALLOC0 (static: Y, size: 4, align: 4) {
-    2a 00 00 00                                     │ *...
-}
+ALLOC0 (static: Y)

tests/mir-opt/const_promotion_extern_static.BAR.PromoteTemps.diff

@@ -38,9 +38,7 @@
       bb2 (cleanup): {
           resume;
       }
-- }
-- 
-- ALLOC0 (static: Y, size: 4, align: 4) {
--     2a 00 00 00                                     │ *...
   }
+- 
+- ALLOC0 (static: Y)
 

tests/ui/const-generics/normalizing_with_unconstrained_impl_params.rs

@@ -0,0 +1,18 @@
+//! Regression test for <https://github.com/rust-lang/rust/issues/122638>.
+//@ check-fail
+#![feature(min_specialization)]
+impl<'a, T: std::fmt::Debug, const N: usize> Iterator for ConstChunksExact<'a, T, { N }> {
+    //~^ ERROR not all trait items implemented, missing: `Item` [E0046]
+    fn next(&mut self) -> Option<Self::Item> {}
+    //~^ ERROR mismatched types [E0308]
+}
+struct ConstChunksExact<'a, T: '_, const assert: usize> {}
+//~^ ERROR `'_` cannot be used here [E0637]
+//~| ERROR lifetime parameter `'a` is never used [E0392]
+//~| ERROR type parameter `T` is never used [E0392]
+impl<'a, T: std::fmt::Debug, const N: usize> Iterator for ConstChunksExact<'a, T, {}> {
+    //~^ ERROR mismatched types [E0308]
+    //~| ERROR the const parameter `N` is not constrained by the impl trait, self type, or predicates [E0207]
+    type Item = &'a [T; N]; }
+
+fn main() {}

tests/ui/const-generics/normalizing_with_unconstrained_impl_params.stderr

@@ -0,0 +1,60 @@
+error[E0637]: `'_` cannot be used here
+  --> $DIR/normalizing_with_unconstrained_impl_params.rs:9:32
+   |
+LL | struct ConstChunksExact<'a, T: '_, const assert: usize> {}
+   |                                ^^ `'_` is a reserved lifetime name
+
+error[E0308]: mismatched types
+  --> $DIR/normalizing_with_unconstrained_impl_params.rs:13:83
+   |
+LL | impl<'a, T: std::fmt::Debug, const N: usize> Iterator for ConstChunksExact<'a, T, {}> {
+   |                                                                                   ^^ expected `usize`, found `()`
+
+error[E0046]: not all trait items implemented, missing: `Item`
+  --> $DIR/normalizing_with_unconstrained_impl_params.rs:4:1
+   |
+LL | impl<'a, T: std::fmt::Debug, const N: usize> Iterator for ConstChunksExact<'a, T, { N }> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `Item` in implementation
+   |
+   = help: implement the missing item: `type Item = /* Type */;`
+
+error[E0392]: lifetime parameter `'a` is never used
+  --> $DIR/normalizing_with_unconstrained_impl_params.rs:9:25
+   |
+LL | struct ConstChunksExact<'a, T: '_, const assert: usize> {}
+   |                         ^^ unused lifetime parameter
+   |
+   = help: consider removing `'a`, referring to it in a field, or using a marker such as `PhantomData`
+
+error[E0392]: type parameter `T` is never used
+  --> $DIR/normalizing_with_unconstrained_impl_params.rs:9:29
+   |
+LL | struct ConstChunksExact<'a, T: '_, const assert: usize> {}
+   |                             ^ unused type parameter
+   |
+   = help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
+
+error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
+  --> $DIR/normalizing_with_unconstrained_impl_params.rs:13:30
+   |
+LL | impl<'a, T: std::fmt::Debug, const N: usize> Iterator for ConstChunksExact<'a, T, {}> {
+   |                              ^^^^^^^^^^^^^^ unconstrained const parameter
+   |
+   = note: expressions using a const parameter must map each value to a distinct output value
+   = note: proving the result of expressions other than the parameter are unique is not supported
+
+error[E0308]: mismatched types
+  --> $DIR/normalizing_with_unconstrained_impl_params.rs:6:27
+   |
+LL |     fn next(&mut self) -> Option<Self::Item> {}
+   |        ----               ^^^^^^^^^^^^^^^^^^ expected `Option<_>`, found `()`
+   |        |
+   |        implicitly returns `()` as its body has no tail or `return` expression
+   |
+   = note:   expected enum `Option<_>`
+           found unit type `()`
+
+error: aborting due to 7 previous errors
+
+Some errors have detailed explanations: E0046, E0207, E0308, E0392, E0637.
+For more information about an error, try `rustc --explain E0046`.

tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.fixed

@@ -0,0 +1,22 @@
+//@ run-rustfix
+#![deny(unused_assignments, unused_variables)]
+struct Object;
+
+fn change_object(object: &mut Object) { //~ HELP you might have meant to mutate
+    let object2 = Object;
+    *object = object2; //~ ERROR mismatched types
+}
+
+fn change_object2(object: &mut Object) { //~ ERROR variable `object` is assigned to, but never used
+    //~^ HELP you might have meant to mutate
+    let object2 = Object;
+    *object = object2;
+    //~^ ERROR `object2` does not live long enough
+    //~| ERROR value assigned to `object` is never read
+}
+
+fn main() {
+    let mut object = Object;
+    change_object(&mut object);
+    change_object2(&mut object);
+}

tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs

@@ -0,0 +1,22 @@
+//@ run-rustfix
+#![deny(unused_assignments, unused_variables)]
+struct Object;
+
+fn change_object(mut object: &Object) { //~ HELP you might have meant to mutate
+    let object2 = Object;
+    object = object2; //~ ERROR mismatched types
+}
+
+fn change_object2(mut object: &Object) { //~ ERROR variable `object` is assigned to, but never used
+    //~^ HELP you might have meant to mutate
+    let object2 = Object;
+    object = &object2;
+    //~^ ERROR `object2` does not live long enough
+    //~| ERROR value assigned to `object` is never read
+}
+
+fn main() {
+    let mut object = Object;
+    change_object(&mut object);
+    change_object2(&mut object);
+}

tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.stderr

@@ -0,0 +1,69 @@
+error[E0308]: mismatched types
+  --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:7:14
+   |
+LL | fn change_object(mut object: &Object) {
+   |                              ------- expected due to this parameter type
+LL |     let object2 = Object;
+LL |     object = object2;
+   |              ^^^^^^^ expected `&Object`, found `Object`
+   |
+help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding
+   |
+LL ~ fn change_object(object: &mut Object) {
+LL |     let object2 = Object;
+LL ~     *object = object2;
+   |
+
+error: value assigned to `object` is never read
+  --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:13:5
+   |
+LL |     object = &object2;
+   |     ^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:2:9
+   |
+LL | #![deny(unused_assignments, unused_variables)]
+   |         ^^^^^^^^^^^^^^^^^^
+help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding
+   |
+LL ~ fn change_object2(object: &mut Object) {
+LL |
+LL |     let object2 = Object;
+LL ~     *object = object2;
+   |
+
+error: variable `object` is assigned to, but never used
+  --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:10:23
+   |
+LL | fn change_object2(mut object: &Object) {
+   |                       ^^^^^^
+   |
+   = note: consider using `_object` instead
+note: the lint level is defined here
+  --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:2:29
+   |
+LL | #![deny(unused_assignments, unused_variables)]
+   |                             ^^^^^^^^^^^^^^^^
+
+error[E0597]: `object2` does not live long enough
+  --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:13:14
+   |
+LL | fn change_object2(mut object: &Object) {
+   |                               - let's call the lifetime of this reference `'1`
+LL |
+LL |     let object2 = Object;
+   |         ------- binding `object2` declared here
+LL |     object = &object2;
+   |     ---------^^^^^^^^
+   |     |        |
+   |     |        borrowed value does not live long enough
+   |     assignment requires that `object2` is borrowed for `'1`
+...
+LL | }
+   | - `object2` dropped here while still borrowed
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0308, E0597.
+For more information about an error, try `rustc --explain E0308`.

tests/ui/impl-trait/precise-capturing/redundant.rs

@@ -1,24 +1,24 @@
 //@ edition: 2024
-//@ check-pass
 
 #![feature(precise_capturing_in_traits)]
+#![deny(impl_trait_redundant_captures)]
 
 fn hello<'a>() -> impl Sized + use<'a> {}
-//~^ WARN all possible in-scope parameters are already captured
+//~^ ERROR all possible in-scope parameters are already captured
 
 struct Inherent;
 impl Inherent {
     fn inherent(&self) -> impl Sized + use<'_> {}
-    //~^ WARN all possible in-scope parameters are already captured
+    //~^ ERROR all possible in-scope parameters are already captured
 }
 
 trait Test<'a> {
     fn in_trait() -> impl Sized + use<'a, Self>;
-    //~^ WARN all possible in-scope parameters are already captured
+    //~^ ERROR all possible in-scope parameters are already captured
 }
 impl<'a> Test<'a> for () {
     fn in_trait() -> impl Sized + use<'a> {}
-    //~^ WARN all possible in-scope parameters are already captured
+    //~^ ERROR all possible in-scope parameters are already captured
 }
 
 fn main() {}

tests/ui/impl-trait/precise-capturing/redundant.stderr

@@ -1,36 +1,40 @@
-warning: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
+error: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
   --> $DIR/redundant.rs:6:19
    |
 LL | fn hello<'a>() -> impl Sized + use<'a> {}
    |                   ^^^^^^^^^^^^^-------
    |                                |
    |                                help: remove the `use<...>` syntax
    |
-   = note: `#[warn(impl_trait_redundant_captures)]` on by default
+note: the lint level is defined here
+  --> $DIR/redundant.rs:4:9
+   |
+LL | #![deny(impl_trait_redundant_captures)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-warning: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
+error: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
   --> $DIR/redundant.rs:11:27
    |
 LL |     fn inherent(&self) -> impl Sized + use<'_> {}
    |                           ^^^^^^^^^^^^^-------
    |                                        |
    |                                        help: remove the `use<...>` syntax
 
-warning: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
+error: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
   --> $DIR/redundant.rs:16:22
    |
 LL |     fn in_trait() -> impl Sized + use<'a, Self>;
    |                      ^^^^^^^^^^^^^-------------
    |                                   |
    |                                   help: remove the `use<...>` syntax
 
-warning: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
+error: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
   --> $DIR/redundant.rs:20:22
    |
 LL |     fn in_trait() -> impl Sized + use<'a> {}
    |                      ^^^^^^^^^^^^^-------
    |                                   |
    |                                   help: remove the `use<...>` syntax
 
-warning: 4 warnings emitted
+error: aborting due to 4 previous errors