Merge pull request rust-lang#4288 from rust-lang/rustup-2025-04-23

Automatic Rustup

Author: RalfJung

compiler/rustc_builtin_macros/src/autodiff.rs

@@ -217,14 +217,12 @@ mod llvm_enzyme {
                 ast::StmtKind::Item(iitem) => extract_item_info(iitem),
                 _ => None,
             },
-            Annotatable::AssocItem(assoc_item, Impl { of_trait: false }) => {
-                match &assoc_item.kind {
-                    ast::AssocItemKind::Fn(box ast::Fn { sig, ident, .. }) => {
-                        Some((assoc_item.vis.clone(), sig.clone(), ident.clone()))
-                    }
-                    _ => None,
+            Annotatable::AssocItem(assoc_item, Impl { .. }) => match &assoc_item.kind {
+                ast::AssocItemKind::Fn(box ast::Fn { sig, ident, .. }) => {
+                    Some((assoc_item.vis.clone(), sig.clone(), ident.clone()))
                 }
-            }
+                _ => None,
+            },
             _ => None,
         }) else {
             dcx.emit_err(errors::AutoDiffInvalidApplication { span: item.span() });
@@ -365,7 +363,7 @@ mod llvm_enzyme {
                 }
                 Annotatable::Item(iitem.clone())
             }
-            Annotatable::AssocItem(ref mut assoc_item, i @ Impl { of_trait: false }) => {
+            Annotatable::AssocItem(ref mut assoc_item, i @ Impl { .. }) => {
                 if !assoc_item.attrs.iter().any(|a| same_attribute(&a.kind, &attr.kind)) {
                     assoc_item.attrs.push(attr);
                 }

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -872,8 +872,21 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
         // # Function pointers
         // (both global from `alloc_map` and local from `extra_fn_ptr_map`)
-        if self.get_fn_alloc(id).is_some() {
-            return AllocInfo::new(Size::ZERO, Align::ONE, AllocKind::Function, Mutability::Not);
+        if let Some(fn_val) = self.get_fn_alloc(id) {
+            let align = match fn_val {
+                FnVal::Instance(instance) => {
+                    // Function alignment can be set globally with the `-Zmin-function-alignment=<n>` flag;
+                    // the alignment from a `#[repr(align(<n>))]` is used if it specifies a higher alignment.
+                    let fn_align = self.tcx.codegen_fn_attrs(instance.def_id()).alignment;
+                    let global_align = self.tcx.sess.opts.unstable_opts.min_function_alignment;
+
+                    Ord::max(global_align, fn_align).unwrap_or(Align::ONE)
+                }
+                // Machine-specific extra functions currently do not support alignment restrictions.
+                FnVal::Other(_) => Align::ONE,
+            };
+
+            return AllocInfo::new(Size::ZERO, align, AllocKind::Function, Mutability::Not);
         }
 
         // # Global allocations

compiler/rustc_hir_typeck/src/expr.rs

@@ -3289,8 +3289,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         err.multipart_suggestion(
             format!("{val} is a raw pointer; try dereferencing it"),
             vec![
-                (base.span.shrink_to_lo(), "(*".to_string()),
-                (base.span.shrink_to_hi(), ")".to_string()),
+                (base.span.shrink_to_lo(), "(*".into()),
+                (base.span.between(field.span), format!(").")),
             ],
             Applicability::MaybeIncorrect,
         );

compiler/rustc_parse/messages.ftl

@@ -246,9 +246,9 @@ parse_expected_struct_field = expected one of `,`, `:`, or `{"}"}`, found `{$tok
 
 parse_expected_trait_in_trait_impl_found_type = expected a trait, found type
 
-parse_expr_rarrow_call = `->` used for field access or method call
+parse_expr_rarrow_call = `->` is not valid syntax for field accesses and method calls
     .suggestion = try using `.` instead
-    .help = the `.` operator will dereference the value if needed
+    .help = the `.` operator will automatically dereference the value, except if the value is a raw pointer
 
 parse_extern_crate_name_with_dashes = crate name using dashes are not valid in `extern crate` statements
     .label = dash-separated idents are not valid

compiler/rustc_parse/src/parser/expr.rs

@@ -26,6 +26,7 @@ use rustc_macros::Subdiagnostic;
 use rustc_session::errors::{ExprParenthesesNeeded, report_lit_error};
 use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP;
+use rustc_span::edition::Edition;
 use rustc_span::source_map::{self, Spanned};
 use rustc_span::{BytePos, ErrorGuaranteed, Ident, Pos, Span, Symbol, kw, sym};
 use thin_vec::{ThinVec, thin_vec};
@@ -2145,6 +2146,17 @@ impl<'a> Parser<'a> {
     /// Keep this in sync with `Token::can_begin_literal_maybe_minus` and
     /// `Lit::from_token` (excluding unary negation).
     fn eat_token_lit(&mut self) -> Option<token::Lit> {
+        let check_expr = |expr: P<Expr>| {
+            if let ast::ExprKind::Lit(token_lit) = expr.kind {
+                Some(token_lit)
+            } else if let ast::ExprKind::Unary(UnOp::Neg, inner) = &expr.kind
+                && let ast::Expr { kind: ast::ExprKind::Lit(_), .. } = **inner
+            {
+                None
+            } else {
+                panic!("unexpected reparsed expr/literal: {:?}", expr.kind);
+            }
+        };
         match self.token.uninterpolate().kind {
             token::Ident(name, IdentIsRaw::No) if name.is_bool_lit() => {
                 self.bump();
@@ -2158,26 +2170,15 @@ impl<'a> Parser<'a> {
                 let lit = self
                     .eat_metavar_seq(MetaVarKind::Literal, |this| this.parse_literal_maybe_minus())
                     .expect("metavar seq literal");
-                let ast::ExprKind::Lit(token_lit) = lit.kind else {
-                    panic!("didn't reparse a literal");
-                };
-                Some(token_lit)
+                check_expr(lit)
             }
             token::OpenInvisible(InvisibleOrigin::MetaVar(
                 mv_kind @ MetaVarKind::Expr { can_begin_literal_maybe_minus: true, .. },
             )) => {
                 let expr = self
                     .eat_metavar_seq(mv_kind, |this| this.parse_expr())
                     .expect("metavar seq expr");
-                if let ast::ExprKind::Lit(token_lit) = expr.kind {
-                    Some(token_lit)
-                } else if let ast::ExprKind::Unary(UnOp::Neg, inner) = &expr.kind
-                    && let ast::Expr { kind: ast::ExprKind::Lit(_), .. } = **inner
-                {
-                    None
-                } else {
-                    panic!("unexpected reparsed expr: {:?}", expr.kind);
-                }
+                check_expr(expr)
             }
             _ => None,
         }
@@ -2602,7 +2603,10 @@ impl<'a> Parser<'a> {
     /// Parses an `if` expression (`if` token already eaten).
     fn parse_expr_if(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.prev_token.span;
-        let cond = self.parse_expr_cond()?;
+        // Scoping code checks the top level edition of the `if`; let's match it here.
+        // The `CondChecker` also checks the edition of the `let` itself, just to make sure.
+        let let_chains_policy = LetChainsPolicy::EditionDependent { current_edition: lo.edition() };
+        let cond = self.parse_expr_cond(let_chains_policy)?;
         self.parse_if_after_cond(lo, cond)
     }
 
@@ -2711,18 +2715,17 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses the condition of a `if` or `while` expression.
+    ///
+    /// The specified `edition` in `let_chains_policy` should be that of the whole `if` construct,
+    /// i.e. the same span we use to later decide whether the drop behaviour should be that of
+    /// edition `..=2021` or that of `2024..`.
     // Public because it is used in rustfmt forks such as https://github.com/tucant/rustfmt/blob/30c83df9e1db10007bdd16dafce8a86b404329b2/src/parse/macros/html.rs#L57 for custom if expressions.
-    pub fn parse_expr_cond(&mut self) -> PResult<'a, P<Expr>> {
+    pub fn parse_expr_cond(&mut self, let_chains_policy: LetChainsPolicy) -> PResult<'a, P<Expr>> {
         let attrs = self.parse_outer_attributes()?;
         let (mut cond, _) =
             self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, attrs)?;
 
-        CondChecker::new(self).visit_expr(&mut cond);
-
-        if let ExprKind::Let(_, _, _, Recovered::No) = cond.kind {
-            // Remove the last feature gating of a `let` expression since it's stable.
-            self.psess.gated_spans.ungate_last(sym::let_chains, cond.span);
-        }
+        CondChecker::new(self, let_chains_policy).visit_expr(&mut cond);
 
         Ok(cond)
     }
@@ -3017,7 +3020,8 @@ impl<'a> Parser<'a> {
 
     /// Parses a `while` or `while let` expression (`while` token already eaten).
     fn parse_expr_while(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
-        let cond = self.parse_expr_cond().map_err(|mut err| {
+        let policy = LetChainsPolicy::EditionDependent { current_edition: lo.edition() };
+        let cond = self.parse_expr_cond(policy).map_err(|mut err| {
             err.span_label(lo, "while parsing the condition of this `while` expression");
             err
         })?;
@@ -3401,17 +3405,17 @@ impl<'a> Parser<'a> {
     }
 
     fn parse_match_arm_guard(&mut self) -> PResult<'a, Option<P<Expr>>> {
-        // Used to check the `let_chains` and `if_let_guard` features mostly by scanning
+        // Used to check the `if_let_guard` feature mostly by scanning
         // `&&` tokens.
-        fn check_let_expr(expr: &Expr) -> (bool, bool) {
+        fn has_let_expr(expr: &Expr) -> bool {
             match &expr.kind {
                 ExprKind::Binary(BinOp { node: BinOpKind::And, .. }, lhs, rhs) => {
-                    let lhs_rslt = check_let_expr(lhs);
-                    let rhs_rslt = check_let_expr(rhs);
-                    (lhs_rslt.0 || rhs_rslt.0, false)
+                    let lhs_rslt = has_let_expr(lhs);
+                    let rhs_rslt = has_let_expr(rhs);
+                    lhs_rslt || rhs_rslt
                 }
-                ExprKind::Let(..) => (true, true),
-                _ => (false, true),
+                ExprKind::Let(..) => true,
+                _ => false,
             }
         }
         if !self.eat_keyword(exp!(If)) {
@@ -3422,14 +3426,9 @@ impl<'a> Parser<'a> {
         let if_span = self.prev_token.span;
         let mut cond = self.parse_match_guard_condition()?;
 
-        CondChecker::new(self).visit_expr(&mut cond);
+        CondChecker::new(self, LetChainsPolicy::AlwaysAllowed).visit_expr(&mut cond);
 
-        let (has_let_expr, does_not_have_bin_op) = check_let_expr(&cond);
-        if has_let_expr {
-            if does_not_have_bin_op {
-                // Remove the last feature gating of a `let` expression since it's stable.
-                self.psess.gated_spans.ungate_last(sym::let_chains, cond.span);
-            }
+        if has_let_expr(&cond) {
             let span = if_span.to(cond.span);
             self.psess.gated_spans.gate(sym::if_let_guard, span);
         }
@@ -3456,7 +3455,7 @@ impl<'a> Parser<'a> {
                     unreachable!()
                 };
                 self.psess.gated_spans.ungate_last(sym::guard_patterns, cond.span);
-                CondChecker::new(self).visit_expr(&mut cond);
+                CondChecker::new(self, LetChainsPolicy::AlwaysAllowed).visit_expr(&mut cond);
                 let right = self.prev_token.span;
                 self.dcx().emit_err(errors::ParenthesesInMatchPat {
                     span: vec![left, right],
@@ -4027,7 +4026,14 @@ pub(crate) enum ForbiddenLetReason {
     NotSupportedParentheses(#[primary_span] Span),
 }
 
-/// Visitor to check for invalid/unstable use of `ExprKind::Let` that can't
+/// Whether let chains are allowed on all editions, or it's edition dependent (allowed only on
+/// 2024 and later). In case of edition dependence, specify the currently present edition.
+pub enum LetChainsPolicy {
+    AlwaysAllowed,
+    EditionDependent { current_edition: Edition },
+}
+
+/// Visitor to check for invalid use of `ExprKind::Let` that can't
 /// easily be caught in parsing. For example:
 ///
 /// ```rust,ignore (example)
@@ -4038,19 +4044,29 @@ pub(crate) enum ForbiddenLetReason {
 /// ```
 struct CondChecker<'a> {
     parser: &'a Parser<'a>,
+    let_chains_policy: LetChainsPolicy,
+    depth: u32,
     forbid_let_reason: Option<ForbiddenLetReason>,
     missing_let: Option<errors::MaybeMissingLet>,
     comparison: Option<errors::MaybeComparison>,
 }
 
 impl<'a> CondChecker<'a> {
-    fn new(parser: &'a Parser<'a>) -> Self {
-        CondChecker { parser, forbid_let_reason: None, missing_let: None, comparison: None }
+    fn new(parser: &'a Parser<'a>, let_chains_policy: LetChainsPolicy) -> Self {
+        CondChecker {
+            parser,
+            forbid_let_reason: None,
+            missing_let: None,
+            comparison: None,
+            let_chains_policy,
+            depth: 0,
+        }
     }
 }
 
 impl MutVisitor for CondChecker<'_> {
     fn visit_expr(&mut self, e: &mut P<Expr>) {
+        self.depth += 1;
         use ForbiddenLetReason::*;
 
         let span = e.span;
@@ -4065,8 +4081,16 @@ impl MutVisitor for CondChecker<'_> {
                             comparison: self.comparison,
                         },
                     ));
-                } else {
-                    self.parser.psess.gated_spans.gate(sym::let_chains, span);
+                } else if self.depth > 1 {
+                    // Top level `let` is always allowed; only gate chains
+                    match self.let_chains_policy {
+                        LetChainsPolicy::AlwaysAllowed => (),
+                        LetChainsPolicy::EditionDependent { current_edition } => {
+                            if !current_edition.at_least_rust_2024() || !span.at_least_rust_2024() {
+                                self.parser.psess.gated_spans.gate(sym::let_chains, span);
+                            }
+                        }
+                    }
                 }
             }
             ExprKind::Binary(Spanned { node: BinOpKind::And, .. }, _, _) => {
@@ -4168,5 +4192,6 @@ impl MutVisitor for CondChecker<'_> {
                 // These would forbid any let expressions they contain already.
             }
         }
+        self.depth -= 1;
     }
 }

library/core/src/num/f128.rs

@@ -145,6 +145,9 @@ impl f128 {
     pub const RADIX: u32 = 2;
 
     /// Number of significant digits in base 2.
+    ///
+    /// Note that the size of the mantissa in the bitwise representation is one
+    /// smaller than this since the leading 1 is not stored explicitly.
     #[unstable(feature = "f128", issue = "116909")]
     pub const MANTISSA_DIGITS: u32 = 113;
 

library/core/src/num/f16.rs

@@ -140,6 +140,9 @@ impl f16 {
     pub const RADIX: u32 = 2;
 
     /// Number of significant digits in base 2.
+    ///
+    /// Note that the size of the mantissa in the bitwise representation is one
+    /// smaller than this since the leading 1 is not stored explicitly.
     #[unstable(feature = "f16", issue = "116909")]
     pub const MANTISSA_DIGITS: u32 = 11;
 

library/core/src/num/f32.rs

@@ -390,6 +390,9 @@ impl f32 {
     pub const RADIX: u32 = 2;
 
     /// Number of significant digits in base 2.
+    ///
+    /// Note that the size of the mantissa in the bitwise representation is one
+    /// smaller than this since the leading 1 is not stored explicitly.
     #[stable(feature = "assoc_int_consts", since = "1.43.0")]
     pub const MANTISSA_DIGITS: u32 = 24;
 

library/core/src/num/f64.rs

@@ -390,6 +390,9 @@ impl f64 {
     pub const RADIX: u32 = 2;
 
     /// Number of significant digits in base 2.
+    ///
+    /// Note that the size of the mantissa in the bitwise representation is one
+    /// smaller than this since the leading 1 is not stored explicitly.
     #[stable(feature = "assoc_int_consts", since = "1.43.0")]
     pub const MANTISSA_DIGITS: u32 = 53;
     /// Approximate number of significant digits in base 10.

library/std/src/sys/process/unix/unix.rs

@@ -415,6 +415,7 @@ impl Command {
         all(target_os = "linux", target_env = "musl"),
         target_os = "nto",
         target_vendor = "apple",
+        target_os = "cygwin",
     )))]
     fn posix_spawn(
         &mut self,
@@ -433,6 +434,7 @@ impl Command {
         all(target_os = "linux", target_env = "musl"),
         target_os = "nto",
         target_vendor = "apple",
+        target_os = "cygwin",
     ))]
     fn posix_spawn(
         &mut self,
@@ -584,7 +586,7 @@ impl Command {
         /// Some platforms can set a new working directory for a spawned process in the
         /// `posix_spawn` path. This function looks up the function pointer for adding
         /// such an action to a `posix_spawn_file_actions_t` struct.
-        #[cfg(not(all(target_os = "linux", target_env = "musl")))]
+        #[cfg(not(any(all(target_os = "linux", target_env = "musl"), target_os = "cygwin")))]
         fn get_posix_spawn_addchdir() -> Option<PosixSpawnAddChdirFn> {
             use crate::sys::weak::weak;
 
@@ -618,7 +620,9 @@ impl Command {
         /// Weak symbol lookup doesn't work with statically linked libcs, so in cases
         /// where static linking is possible we need to either check for the presence
         /// of the symbol at compile time or know about it upfront.
-        #[cfg(all(target_os = "linux", target_env = "musl"))]
+        ///
+        /// Cygwin doesn't support weak symbol, so just link it.
+        #[cfg(any(all(target_os = "linux", target_env = "musl"), target_os = "cygwin"))]
         fn get_posix_spawn_addchdir() -> Option<PosixSpawnAddChdirFn> {
             // Our minimum required musl supports this function, so we can just use it.
             Some(libc::posix_spawn_file_actions_addchdir_np)

library/std/tests/floats/f128.rs

@@ -112,6 +112,8 @@ fn test_nan() {
     assert!(!nan.is_sign_negative());
     assert!(!nan.is_normal());
     assert_eq!(Fp::Nan, nan.classify());
+    // Ensure the quiet bit is set.
+    assert!(nan.to_bits() & (1 << (f128::MANTISSA_DIGITS - 2)) != 0);
 }
 
 #[test]

library/std/tests/floats/f16.rs

@@ -95,6 +95,8 @@ fn test_nan() {
     assert!(!nan.is_sign_negative());
     assert!(!nan.is_normal());
     assert_eq!(Fp::Nan, nan.classify());
+    // Ensure the quiet bit is set.
+    assert!(nan.to_bits() & (1 << (f16::MANTISSA_DIGITS - 2)) != 0);
 }
 
 #[test]