Rollup of 8 pull requests

compiler/rustc_lint/src/context.rs

@@ -24,7 +24,7 @@ use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers, TyAndLayout};
 use rustc_middle::ty::print::{PrintError, PrintTraitRefExt as _, Printer, with_no_trimmed_paths};
 use rustc_middle::ty::{self, GenericArg, RegisteredTools, Ty, TyCtxt, TypingEnv, TypingMode};
 use rustc_session::lint::{FutureIncompatibleInfo, Lint, LintBuffer, LintExpectationId, LintId};
-use rustc_session::{LintStoreMarker, Session};
+use rustc_session::{DynLintStore, Session};
 use rustc_span::edit_distance::find_best_match_for_names;
 use rustc_span::{Ident, Span, Symbol, sym};
 use tracing::debug;
@@ -62,7 +62,13 @@ pub struct LintStore {
     lint_groups: FxIndexMap<&'static str, LintGroup>,
 }
 
-impl LintStoreMarker for LintStore {}
+impl DynLintStore for LintStore {
+    fn lint_groups_iter(&self) -> Box<dyn Iterator<Item = rustc_session::LintGroup> + '_> {
+        Box::new(self.get_lint_groups().map(|(name, lints, is_externally_loaded)| {
+            rustc_session::LintGroup { name, lints, is_externally_loaded }
+        }))
+    }
+}
 
 /// The target of the `by_name` map, which accounts for renaming/deprecation.
 #[derive(Debug)]

compiler/rustc_middle/src/lint.rs

@@ -211,11 +211,28 @@ impl LintExpectation {
 }
 
 fn explain_lint_level_source(
+    sess: &Session,
     lint: &'static Lint,
     level: Level,
     src: LintLevelSource,
     err: &mut Diag<'_, ()>,
 ) {
+    // Find the name of the lint group that contains the given lint.
+    // Assumes the lint only belongs to one group.
+    let lint_group_name = |lint| {
+        let lint_groups_iter = sess.lint_groups_iter();
+        let lint_id = LintId::of(lint);
+        lint_groups_iter
+            .filter(|lint_group| !lint_group.is_externally_loaded)
+            .find(|lint_group| {
+                lint_group
+                    .lints
+                    .iter()
+                    .find(|lint_group_lint| **lint_group_lint == lint_id)
+                    .is_some()
+            })
+            .map(|lint_group| lint_group.name)
+    };
     let name = lint.name_lower();
     if let Level::Allow = level {
         // Do not point at `#[allow(compat_lint)]` as the reason for a compatibility lint
@@ -224,7 +241,15 @@ fn explain_lint_level_source(
     }
     match src {
         LintLevelSource::Default => {
-            err.note_once(format!("`#[{}({})]` on by default", level.as_str(), name));
+            let level_str = level.as_str();
+            match lint_group_name(lint) {
+                Some(group_name) => {
+                    err.note_once(format!("`#[{level_str}({name})]` (part of `#[{level_str}({group_name})]`) on by default"));
+                }
+                None => {
+                    err.note_once(format!("`#[{level_str}({name})]` on by default"));
+                }
+            }
         }
         LintLevelSource::CommandLine(lint_flag_val, orig_level) => {
             let flag = orig_level.to_cmd_flag();
@@ -427,7 +452,7 @@ pub fn lint_level(
             decorate(&mut err);
         }
 
-        explain_lint_level_source(lint, level, src, &mut err);
+        explain_lint_level_source(sess, lint, level, src, &mut err);
         err.emit()
     }
     lint_level_impl(sess, lint, level, span, Box::new(decorate))

compiler/rustc_session/src/session.rs

@@ -44,6 +44,7 @@ use crate::config::{
     SwitchWithOptPath,
 };
 use crate::filesearch::FileSearch;
+use crate::lint::LintId;
 use crate::parse::{ParseSess, add_feature_diagnostics};
 use crate::search_paths::SearchPath;
 use crate::{errors, filesearch, lint};
@@ -139,7 +140,10 @@ pub struct CompilerIO {
     pub temps_dir: Option<PathBuf>,
 }
 
-pub trait LintStoreMarker: Any + DynSync + DynSend {}
+pub trait DynLintStore: Any + DynSync + DynSend {
+    /// Provides a way to access lint groups without depending on `rustc_lint`
+    fn lint_groups_iter(&self) -> Box<dyn Iterator<Item = LintGroup> + '_>;
+}
 
 /// Represents the data associated with a compilation
 /// session for a single crate.
@@ -164,7 +168,7 @@ pub struct Session {
     pub code_stats: CodeStats,
 
     /// This only ever stores a `LintStore` but we don't want a dependency on that type here.
-    pub lint_store: Option<Arc<dyn LintStoreMarker>>,
+    pub lint_store: Option<Arc<dyn DynLintStore>>,
 
     /// Cap lint level specified by a driver specifically.
     pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
@@ -240,6 +244,12 @@ impl CodegenUnits {
     }
 }
 
+pub struct LintGroup {
+    pub name: &'static str,
+    pub lints: Vec<LintId>,
+    pub is_externally_loaded: bool,
+}
+
 impl Session {
     pub fn miri_unleashed_feature(&self, span: Span, feature_gate: Option<Symbol>) {
         self.miri_unleashed_features.lock().push((span, feature_gate));
@@ -596,6 +606,13 @@ impl Session {
             (&*self.target.staticlib_prefix, &*self.target.staticlib_suffix)
         }
     }
+
+    pub fn lint_groups_iter(&self) -> Box<dyn Iterator<Item = LintGroup> + '_> {
+        match self.lint_store {
+            Some(ref lint_store) => lint_store.lint_groups_iter(),
+            None => Box::new(std::iter::empty()),
+        }
+    }
 }
 
 // JUSTIFICATION: defn of the suggested wrapper fns

compiler/rustc_target/src/spec/targets/x86_64_apple_darwin.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target,
         metadata: TargetMetadata {
             description: Some("x86_64 Apple macOS (10.12+, Sierra+)".into()),
-            tier: Some(1),
+            tier: Some(2),
             host_tools: Some(true),
             std: Some(true),
         },

library/Cargo.lock

@@ -336,9 +336,9 @@ dependencies = [
 name = "std_detect"
 version = "0.1.5"
 dependencies = [
- "alloc",
- "core",
  "libc",
+ "rustc-std-workspace-alloc",
+ "rustc-std-workspace-core",
 ]
 
 [[package]]

library/core/src/cmp.rs

@@ -1554,6 +1554,9 @@ pub fn min<T: Ord>(v1: T, v2: T) -> T {
 ///
 /// Returns the first argument if the comparison determines them to be equal.
 ///
+/// The parameter order is preserved when calling the `compare` function, i.e. `v1` is
+/// always passed as the first argument and `v2` as the second.
+///
 /// # Examples
 ///
 /// ```
@@ -1574,7 +1577,7 @@ pub fn min<T: Ord>(v1: T, v2: T) -> T {
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
 pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
-    if compare(&v2, &v1).is_lt() { v2 } else { v1 }
+    if compare(&v1, &v2).is_le() { v1 } else { v2 }
 }
 
 /// Returns the element that gives the minimum value from the specified function.
@@ -1646,6 +1649,9 @@ pub fn max<T: Ord>(v1: T, v2: T) -> T {
 ///
 /// Returns the second argument if the comparison determines them to be equal.
 ///
+/// The parameter order is preserved when calling the `compare` function, i.e. `v1` is
+/// always passed as the first argument and `v2` as the second.
+///
 /// # Examples
 ///
 /// ```
@@ -1666,7 +1672,7 @@ pub fn max<T: Ord>(v1: T, v2: T) -> T {
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
 pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
-    if compare(&v2, &v1).is_lt() { v1 } else { v2 }
+    if compare(&v1, &v2).is_gt() { v1 } else { v2 }
 }
 
 /// Returns the element that gives the maximum value from the specified function.
@@ -1745,6 +1751,9 @@ where
 ///
 /// Returns `[v1, v2]` if the comparison determines them to be equal.
 ///
+/// The parameter order is preserved when calling the `compare` function, i.e. `v1` is
+/// always passed as the first argument and `v2` as the second.
+///
 /// # Examples
 ///
 /// ```
@@ -1769,7 +1778,7 @@ pub fn minmax_by<T, F>(v1: T, v2: T, compare: F) -> [T; 2]
 where
     F: FnOnce(&T, &T) -> Ordering,
 {
-    if compare(&v2, &v1).is_lt() { [v2, v1] } else { [v1, v2] }
+    if compare(&v1, &v2).is_le() { [v1, v2] } else { [v2, v1] }
 }
 
 /// Returns minimum and maximum values with respect to the specified key function.

library/core/src/num/int_macros.rs

@@ -209,6 +209,48 @@ macro_rules! int_impl {
             self & self.wrapping_neg()
         }
 
+        /// Returns the index of the highest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".highest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".highest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn highest_one(self) -> Option<u32> {
+            (self as $UnsignedT).highest_one()
+        }
+
+        /// Returns the index of the lowest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".lowest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".lowest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn lowest_one(self) -> Option<u32> {
+            (self as $UnsignedT).lowest_one()
+        }
+
         /// Returns the bit pattern of `self` reinterpreted as an unsigned integer of the same size.
         ///
         /// This produces the same result as an `as` cast, but ensures that the bit-width remains

library/core/src/num/nonzero.rs

@@ -681,6 +681,54 @@ macro_rules! nonzero_integer {
                 unsafe { NonZero::new_unchecked(n) }
             }
 
+            /// Returns the index of the highest bit set to one in `self`.
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// #![feature(int_lowest_highest_one)]
+            ///
+            /// # use core::num::NonZero;
+            /// # fn main() { test().unwrap(); }
+            /// # fn test() -> Option<()> {
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1)?.highest_one(), 0);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x10)?.highest_one(), 4);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1f)?.highest_one(), 4);")]
+            /// # Some(())
+            /// # }
+            /// ```
+            #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+            #[must_use = "this returns the result of the operation, \
+                          without modifying the original"]
+            #[inline(always)]
+            pub const fn highest_one(self) -> u32 {
+                Self::BITS - 1 - self.leading_zeros()
+            }
+
+            /// Returns the index of the lowest bit set to one in `self`.
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// #![feature(int_lowest_highest_one)]
+            ///
+            /// # use core::num::NonZero;
+            /// # fn main() { test().unwrap(); }
+            /// # fn test() -> Option<()> {
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1)?.lowest_one(), 0);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x10)?.lowest_one(), 4);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1f)?.lowest_one(), 0);")]
+            /// # Some(())
+            /// # }
+            /// ```
+            #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+            #[must_use = "this returns the result of the operation, \
+                          without modifying the original"]
+            #[inline(always)]
+            pub const fn lowest_one(self) -> u32 {
+                self.trailing_zeros()
+            }
+
             /// Returns the number of ones in the binary representation of `self`.
             ///
             /// # Examples

library/core/src/num/uint_macros.rs

@@ -261,6 +261,54 @@ macro_rules! uint_impl {
             self & self.wrapping_neg()
         }
 
+        /// Returns the index of the highest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".highest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".highest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn highest_one(self) -> Option<u32> {
+            match NonZero::new(self) {
+                Some(v) => Some(v.highest_one()),
+                None => None,
+            }
+        }
+
+        /// Returns the index of the lowest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".lowest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".lowest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn lowest_one(self) -> Option<u32> {
+            match NonZero::new(self) {
+                Some(v) => Some(v.lowest_one()),
+                None => None,
+            }
+        }
+
         /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
         ///
         /// This produces the same result as an `as` cast, but ensures that the bit-width remains

library/coretests/tests/lib.rs

@@ -54,6 +54,7 @@
 #![feature(generic_assert_internals)]
 #![feature(hasher_prefixfree_extras)]
 #![feature(hashmap_internals)]
+#![feature(int_lowest_highest_one)]
 #![feature(int_roundings)]
 #![feature(ip)]
 #![feature(is_ascii_octdigit)]