Rollup of 5 pull requests

compiler/rustc_codegen_ssa/src/errors.rs

@@ -8,7 +8,8 @@ use std::process::ExitStatus;
 
 use rustc_errors::codes::*;
 use rustc_errors::{
-    Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, EmissionGuarantee, IntoDiagArg, Level, msg,
+    Diag, DiagArgValue, DiagCtxtHandle, DiagSymbolList, Diagnostic, EmissionGuarantee, IntoDiagArg,
+    Level, msg,
 };
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_middle::ty::layout::LayoutError;
@@ -1249,20 +1250,29 @@ pub(crate) struct FeatureNotValid<'a> {
     #[label("`{$feature}` is not valid for this target")]
     pub span: Span,
     #[subdiagnostic]
-    pub plus_hint: Option<RemovePlusFromFeatureName<'a>>,
+    pub hint: FeatureNotValidHint<'a>,
 }
 
 #[derive(Subdiagnostic)]
-#[suggestion(
-    "consider removing the leading `+` in the feature name",
-    code = "enable = \"{stripped}\"",
-    applicability = "maybe-incorrect",
-    style = "verbose"
-)]
-pub struct RemovePlusFromFeatureName<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub stripped: &'a str,
+pub(crate) enum FeatureNotValidHint<'a> {
+    #[suggestion(
+        "consider removing the leading `+` in the feature name",
+        code = "enable = \"{stripped}\"",
+        applicability = "maybe-incorrect",
+        style = "verbose"
+    )]
+    RemovePlusFromFeatureName {
+        #[primary_span]
+        span: Span,
+        stripped: &'a str,
+    },
+    #[help(
+        "valid names are: {$possibilities}{$and_more ->
+            [0] {\"\"}
+            *[other] {\" \"}and {$and_more} more
+        }"
+    )]
+    ValidFeatureNames { possibilities: DiagSymbolList<&'a str>, and_more: usize },
 }
 
 #[derive(Diagnostic)]

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -9,12 +9,12 @@ use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::builtin::AARCH64_SOFTFLOAT_NEON;
 use rustc_session::parse::feature_err;
-use rustc_span::{Span, Symbol, sym};
+use rustc_span::{Span, Symbol, edit_distance, sym};
 use rustc_target::spec::Arch;
 use rustc_target::target_features::{RUSTC_SPECIFIC_FEATURES, Stability};
 use smallvec::SmallVec;
 
-use crate::errors::{FeatureNotValid, RemovePlusFromFeatureName};
+use crate::errors::{FeatureNotValid, FeatureNotValidHint};
 use crate::{errors, target_features};
 
 /// Compute the enabled target features from the `#[target_feature]` function attribute.
@@ -32,15 +32,25 @@ pub(crate) fn from_target_feature_attr(
     for &(feature, feature_span) in features {
         let feature_str = feature.as_str();
         let Some(stability) = rust_target_features.get(feature_str) else {
-            let plus_hint = feature_str
-                .strip_prefix('+')
-                .filter(|stripped| rust_target_features.contains_key(*stripped))
-                .map(|stripped| RemovePlusFromFeatureName { span: feature_span, stripped });
-            tcx.dcx().emit_err(FeatureNotValid {
-                feature: feature_str,
-                span: feature_span,
-                plus_hint,
-            });
+            let hint = if let Some(stripped) = feature_str.strip_prefix('+')
+                && rust_target_features.contains_key(stripped)
+            {
+                FeatureNotValidHint::RemovePlusFromFeatureName { span: feature_span, stripped }
+            } else {
+                // Show the 5 feature names that are most similar to the input.
+                let mut valid_names: Vec<_> =
+                    rust_target_features.keys().map(|name| name.as_str()).into_sorted_stable_ord();
+                valid_names.sort_by_key(|name| {
+                    edit_distance::edit_distance(name, feature.as_str(), 5).unwrap_or(usize::MAX)
+                });
+                valid_names.truncate(5);
+
+                FeatureNotValidHint::ValidFeatureNames {
+                    possibilities: valid_names.into(),
+                    and_more: rust_target_features.len().saturating_sub(5),
+                }
+            };
+            tcx.dcx().emit_err(FeatureNotValid { feature: feature_str, span: feature_span, hint });
             continue;
         };
 

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_trait.rs

@@ -231,8 +231,9 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         ordered_associated_items.extend(
                             tcx.associated_items(pred.trait_ref.def_id)
                                 .in_definition_order()
-                                // Only associated types & consts can possibly be constrained via a binding.
-                                .filter(|item| item.is_type() || item.is_const())
+                                // Only associated types & type consts can possibly be
+                                // constrained in a trait object type via a binding.
+                                .filter(|item| item.is_type() || item.is_type_const())
                                 // Traits with RPITITs are simply not dyn compatible (for now).
                                 .filter(|item| !item.is_impl_trait_in_trait())
                                 .map(|item| (item.def_id, trait_ref)),

compiler/rustc_middle/src/ty/assoc.rs

@@ -137,8 +137,8 @@ impl AssocItem {
         self.kind.as_def_kind()
     }
 
-    pub fn is_const(&self) -> bool {
-        matches!(self.kind, ty::AssocKind::Const { .. })
+    pub fn is_type_const(&self) -> bool {
+        matches!(self.kind, ty::AssocKind::Const { is_type_const: true, .. })
     }
 
     pub fn is_fn(&self) -> bool {

compiler/rustc_middle/src/ty/sty.rs

@@ -753,7 +753,7 @@ impl<'tcx> Ty<'tcx> {
                     .map(|principal| {
                         tcx.associated_items(principal.def_id())
                             .in_definition_order()
-                            .filter(|item| item.is_type() || item.is_const())
+                            .filter(|item| item.is_type() || item.is_type_const())
                             .filter(|item| !item.is_impl_trait_in_trait())
                             .filter(|item| !tcx.generics_require_sized_self(item.def_id))
                             .count()

compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/transform.rs

@@ -239,7 +239,7 @@ fn trait_object_ty<'tcx>(tcx: TyCtxt<'tcx>, poly_trait_ref: ty::PolyTraitRef<'tc
         .flat_map(|super_poly_trait_ref| {
             tcx.associated_items(super_poly_trait_ref.def_id())
                 .in_definition_order()
-                .filter(|item| item.is_type() || item.is_const())
+                .filter(|item| item.is_type() || item.is_type_const())
                 .filter(|item| !tcx.generics_require_sized_self(item.def_id))
                 .map(move |assoc_item| {
                     super_poly_trait_ref.map_bound(|super_trait_ref| {

compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs

@@ -263,8 +263,13 @@ impl<T> Trait<T> for X {
                             cause.code(),
                         );
                     }
+                    // Don't suggest constraining a projection to something
+                    // containing itself, e.g. `Item = &<I as Iterator>::Item`.
                     (_, ty::Alias(ty::Projection | ty::Inherent, proj_ty))
-                        if !tcx.is_impl_trait_in_trait(proj_ty.def_id) =>
+                        if !tcx.is_impl_trait_in_trait(proj_ty.def_id)
+                            && !tcx
+                                .erase_and_anonymize_regions(values.expected)
+                                .contains(tcx.erase_and_anonymize_regions(values.found)) =>
                     {
                         let msg = || {
                             format!(

library/alloc/src/boxed/thin.rs

@@ -430,3 +430,12 @@ impl<T: ?Sized + Error> Error for ThinBox<T> {
         self.deref().source()
     }
 }
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T> From<T> for ThinBox<T> {
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self::new(value)
+    }
+}

library/alloc/src/rc.rs

@@ -3980,6 +3980,15 @@ impl<T: ?Sized, A: Allocator> AsMut<T> for UniqueRc<T, A> {
 #[unstable(feature = "unique_rc_arc", issue = "112566")]
 impl<T: ?Sized, A: Allocator> Unpin for UniqueRc<T, A> {}
 
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "unique_rc_arc", issue = "112566")]
+impl<T> From<T> for UniqueRc<T> {
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self::new(value)
+    }
+}
+
 #[unstable(feature = "unique_rc_arc", issue = "112566")]
 impl<T: ?Sized + PartialEq, A: Allocator> PartialEq for UniqueRc<T, A> {
     /// Equality for two `UniqueRc`s.

library/alloc/src/sync.rs

@@ -4424,6 +4424,15 @@ impl<T: ?Sized, A: Allocator> AsMut<T> for UniqueArc<T, A> {
     }
 }
 
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "unique_rc_arc", issue = "112566")]
+impl<T> From<T> for UniqueArc<T> {
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self::new(value)
+    }
+}
+
 #[unstable(feature = "unique_rc_arc", issue = "112566")]
 impl<T: ?Sized, A: Allocator> Unpin for UniqueArc<T, A> {}
 

library/core/src/cell/lazy.rs

@@ -366,6 +366,16 @@ impl<T: fmt::Debug, F> fmt::Debug for LazyCell<T, F> {
     }
 }
 
+#[stable(feature = "from_wrapper_impls", since = "CURRENT_RUSTC_VERSION")]
+impl<T, F> From<T> for LazyCell<T, F> {
+    /// Constructs a `LazyCell` that starts already initialized
+    /// with the provided value.
+    #[inline]
+    fn from(value: T) -> Self {
+        Self { state: UnsafeCell::new(State::Init(value)) }
+    }
+}
+
 #[cold]
 #[inline(never)]
 const fn panic_poisoned() -> ! {

library/core/src/panic/unwind_safe.rs

@@ -313,3 +313,16 @@ impl<S: AsyncIterator> AsyncIterator for AssertUnwindSafe<S> {
         self.0.size_hint()
     }
 }
+
+/// If a value's type is already `UnwindSafe`,
+/// wrapping it in `AssertUnwindSafe` is never incorrect.
+#[stable(feature = "from_wrapper_impls", since = "CURRENT_RUSTC_VERSION")]
+impl<T> From<T> for AssertUnwindSafe<T>
+where
+    T: UnwindSafe,
+{
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self(value)
+    }
+}

library/std/src/backtrace/tests.rs

@@ -44,10 +44,9 @@ fn generate_fake_frames() -> Vec<BacktraceFrame> {
 #[test]
 fn test_debug() {
     let backtrace = Backtrace {
-        inner: Inner::Captured(LazyLock::preinit(Capture {
-            actual_start: 1,
-            frames: generate_fake_frames(),
-        })),
+        inner: Inner::Captured(
+            (Capture { actual_start: 1, frames: generate_fake_frames() }).into(),
+        ),
     };
 
     #[rustfmt::skip]
@@ -66,10 +65,9 @@ fn test_debug() {
 #[test]
 fn test_frames() {
     let backtrace = Backtrace {
-        inner: Inner::Captured(LazyLock::preinit(Capture {
-            actual_start: 1,
-            frames: generate_fake_frames(),
-        })),
+        inner: Inner::Captured(
+            (Capture { actual_start: 1, frames: generate_fake_frames() }).into(),
+        ),
     };
 
     let frames = backtrace.frames();

library/std/src/sync/lazy_lock.rs

@@ -105,15 +105,6 @@ impl<T, F: FnOnce() -> T> LazyLock<T, F> {
         LazyLock { once: Once::new(), data: UnsafeCell::new(Data { f: ManuallyDrop::new(f) }) }
     }
 
-    /// Creates a new lazy value that is already initialized.
-    #[inline]
-    #[cfg(test)]
-    pub(crate) fn preinit(value: T) -> LazyLock<T, F> {
-        let once = Once::new();
-        once.call_once(|| {});
-        LazyLock { once, data: UnsafeCell::new(Data { value: ManuallyDrop::new(value) }) }
-    }
-
     /// Consumes this `LazyLock` returning the stored value.
     ///
     /// Returns `Ok(value)` if `Lazy` is initialized and `Err(f)` otherwise.
@@ -404,6 +395,19 @@ impl<T: fmt::Debug, F> fmt::Debug for LazyLock<T, F> {
     }
 }
 
+#[stable(feature = "from_wrapper_impls", since = "CURRENT_RUSTC_VERSION")]
+impl<T, F> From<T> for LazyLock<T, F> {
+    /// Constructs a `LazyLock` that starts already initialized
+    /// with the provided value.
+    #[inline]
+    fn from(value: T) -> Self {
+        LazyLock {
+            once: Once::new_complete(),
+            data: UnsafeCell::new(Data { value: ManuallyDrop::new(value) }),
+        }
+    }
+}
+
 #[cold]
 #[inline(never)]
 fn panic_poisoned() -> ! {

library/std/src/sync/once.rs

@@ -84,6 +84,13 @@ impl Once {
         Once { inner: sys::Once::new() }
     }
 
+    /// Creates a new `Once` value that starts already completed.
+    #[inline]
+    #[must_use]
+    pub(crate) const fn new_complete() -> Once {
+        Once { inner: sys::Once::new_complete() }
+    }
+
     /// Performs an initialization routine once and only once. The given closure
     /// will be executed if this is the first time `call_once` has been called,
     /// and otherwise the routine will *not* be invoked.

library/std/src/sys/sync/once/futex.rs

@@ -75,6 +75,11 @@ impl Once {
         Once { state_and_queued: Futex::new(INCOMPLETE) }
     }
 
+    #[inline]
+    pub const fn new_complete() -> Once {
+        Once { state_and_queued: Futex::new(COMPLETE) }
+    }
+
     #[inline]
     pub fn is_completed(&self) -> bool {
         // Use acquire ordering to make all initialization changes visible to the

library/std/src/sys/sync/once/no_threads.rs

@@ -39,6 +39,11 @@ impl Once {
         Once { state: Cell::new(State::Incomplete) }
     }
 
+    #[inline]
+    pub const fn new_complete() -> Once {
+        Once { state: Cell::new(State::Complete) }
+    }
+
     #[inline]
     pub fn is_completed(&self) -> bool {
         self.state.get() == State::Complete

library/std/src/sys/sync/once/queue.rs

@@ -121,6 +121,11 @@ impl Once {
         Once { state_and_queue: AtomicPtr::new(ptr::without_provenance_mut(INCOMPLETE)) }
     }
 
+    #[inline]
+    pub const fn new_complete() -> Once {
+        Once { state_and_queue: AtomicPtr::new(ptr::without_provenance_mut(COMPLETE)) }
+    }
+
     #[inline]
     pub fn is_completed(&self) -> bool {
         // An `Acquire` load is enough because that makes all the initialization

src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile

@@ -29,5 +29,5 @@ RUN sh /scripts/sccache.sh
 ENV NO_DEBUG_ASSERTIONS=1
 ENV NO_OVERFLOW_CHECKS=1
 
-ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu
-ENV RUST_CHECK_TARGET check-aux
+ENV RUST_CONFIGURE_ARGS="--build=x86_64-unknown-linux-gnu"
+ENV RUST_CHECK_TARGET="check-aux"

src/ci/docker/host-x86_64/x86_64-gnu-debug/Dockerfile

@@ -29,20 +29,19 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-ENV RUSTBUILD_FORCE_CLANG_BASED_TESTS 1
+ENV RUSTBUILD_FORCE_CLANG_BASED_TESTS="1"
 
 # llvm.use-linker conflicts with downloading CI LLVM
-ENV NO_DOWNLOAD_CI_LLVM 1
+ENV NO_DOWNLOAD_CI_LLVM="1"
 
-ENV RUST_CONFIGURE_ARGS \
-      --build=x86_64-unknown-linux-gnu \
+ENV RUST_CONFIGURE_ARGS="--build=x86_64-unknown-linux-gnu \
       --enable-debug \
       --enable-lld \
       --set rust.debuginfo-level-tests=2 \
       --set llvm.use-linker=lld \
       --set target.x86_64-unknown-linux-gnu.linker=clang \
       --set target.x86_64-unknown-linux-gnu.cc=clang \
-      --set target.x86_64-unknown-linux-gnu.cxx=clang++
+      --set target.x86_64-unknown-linux-gnu.cxx=clang++"
 
 # This job checks:
 # - That ui tests can be built with `-Cdebuginfo=1`
@@ -53,7 +52,6 @@ ENV RUST_CONFIGURE_ARGS \
 # - That the tests with `//@ needs-force-clang-based-tests` pass, since they
 #   don't run by default unless RUSTBUILD_FORCE_CLANG_BASED_TESTS is set.
 
-ENV SCRIPT \
-  python3 ../x.py --stage 2 build && \
+ENV SCRIPT="python3 ../x.py --stage 2 build && \
   python3 ../x.py --stage 2 test tests/ui && \
-  python3 ../x.py --stage 2 test tests/run-make tests/run-make-cargo
+  python3 ../x.py --stage 2 test tests/run-make tests/run-make-cargo"