Rollup of 6 pull requests

compiler/rustc_ast/src/token.rs

@@ -881,11 +881,11 @@ impl Token {
     }
 
     pub fn is_qpath_start(&self) -> bool {
-        self == &Lt || self == &Shl
+        matches!(self.kind, Lt | Shl)
     }
 
     pub fn is_path_start(&self) -> bool {
-        self == &PathSep
+        self.kind == PathSep
             || self.is_qpath_start()
             || matches!(self.is_metavar_seq(), Some(MetaVarKind::Path))
             || self.is_path_segment_keyword()

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -6,6 +6,7 @@ use crate::session_diagnostics::{
     NakedFunctionIncompatibleAttribute, NullOnExport, NullOnObjcClass, NullOnObjcSelector,
     ObjcClassExpectedStringLiteral, ObjcSelectorExpectedStringLiteral,
 };
+use crate::target_checking::Policy::AllowSilent;
 
 pub(crate) struct OptimizeParser;
 
@@ -362,6 +363,8 @@ impl<S: Stage> NoArgsAttributeParser<S> for NoMangleParser {
         Allow(Target::Static),
         Allow(Target::Method(MethodKind::Inherent)),
         Allow(Target::Method(MethodKind::TraitImpl)),
+        AllowSilent(Target::Const), // Handled in the `InvalidNoMangleItems` pass
+        Error(Target::Closure),
     ]);
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::NoMangle;
 }

compiler/rustc_attr_parsing/src/target_checking.rs

@@ -31,7 +31,9 @@ impl AllowedTargets {
     pub(crate) fn is_allowed(&self, target: Target) -> AllowedResult {
         match self {
             AllowedTargets::AllowList(list) => {
-                if list.contains(&Policy::Allow(target)) {
+                if list.contains(&Policy::Allow(target))
+                    || list.contains(&Policy::AllowSilent(target))
+                {
                     AllowedResult::Allowed
                 } else if list.contains(&Policy::Warn(target)) {
                     AllowedResult::Warn
@@ -40,7 +42,9 @@ impl AllowedTargets {
                 }
             }
             AllowedTargets::AllowListWarnRest(list) => {
-                if list.contains(&Policy::Allow(target)) {
+                if list.contains(&Policy::Allow(target))
+                    || list.contains(&Policy::AllowSilent(target))
+                {
                     AllowedResult::Allowed
                 } else if list.contains(&Policy::Error(target)) {
                     AllowedResult::Error
@@ -61,17 +65,26 @@ impl AllowedTargets {
         .iter()
         .filter_map(|target| match target {
             Policy::Allow(target) => Some(*target),
+            Policy::AllowSilent(_) => None, // Not listed in possible targets
             Policy::Warn(_) => None,
             Policy::Error(_) => None,
         })
         .collect()
     }
 }
 
+/// This policy determines what diagnostics should be emitted based on the `Target` of the attribute.
 #[derive(Debug, Eq, PartialEq)]
 pub(crate) enum Policy {
+    /// A target that is allowed.
     Allow(Target),
+    /// A target that is allowed and not listed in the possible targets.
+    /// This is useful if the target is checked elsewhere.
+    AllowSilent(Target),
+    /// Emits a FCW on this target.
+    /// This is useful if the target was previously allowed but should not be.
     Warn(Target),
+    /// Emits an error on this target.
     Error(Target),
 }
 

compiler/rustc_builtin_macros/src/format.rs

@@ -69,35 +69,26 @@ struct MacroInput {
 /// Ok((fmtstr, parsed arguments))
 /// ```
 fn parse_args<'a>(ecx: &ExtCtxt<'a>, sp: Span, tts: TokenStream) -> PResult<'a, MacroInput> {
-    let mut args = FormatArguments::new();
-
     let mut p = ecx.new_parser_from_tts(tts);
 
-    if p.token == token::Eof {
-        return Err(ecx.dcx().create_err(errors::FormatRequiresString { span: sp }));
-    }
-
-    let first_token = &p.token;
-
-    let fmtstr = if let token::Literal(lit) = first_token.kind
-        && matches!(lit.kind, token::Str | token::StrRaw(_))
-    {
+    // parse the format string
+    let fmtstr = match p.token.kind {
+        token::Eof => return Err(ecx.dcx().create_err(errors::FormatRequiresString { span: sp })),
         // This allows us to properly handle cases when the first comma
         // after the format string is mistakenly replaced with any operator,
         // which cause the expression parser to eat too much tokens.
-        p.parse_literal_maybe_minus()?
-    } else {
+        token::Literal(token::Lit { kind: token::Str | token::StrRaw(_), .. }) => {
+            p.parse_literal_maybe_minus()?
+        }
         // Otherwise, we fall back to the expression parser.
-        p.parse_expr()?
+        _ => p.parse_expr()?,
     };
 
-    // Only allow implicit captures to be used when the argument is a direct literal
-    // instead of a macro expanding to one.
-    let is_direct_literal = matches!(fmtstr.kind, ExprKind::Lit(_));
-
+    // parse comma FormatArgument pairs
+    let mut args = FormatArguments::new();
     let mut first = true;
-
     while p.token != token::Eof {
+        // parse a comma, or else report an error
         if !p.eat(exp!(Comma)) {
             if first {
                 p.clear_expected_token_types();
@@ -120,9 +111,11 @@ fn parse_args<'a>(ecx: &ExtCtxt<'a>, sp: Span, tts: TokenStream) -> PResult<'a,
             }
         }
         first = false;
+        // accept a trailing comma
         if p.token == token::Eof {
             break;
-        } // accept trailing commas
+        }
+        // parse a FormatArgument
         match p.token.ident() {
             Some((ident, _)) if p.look_ahead(1, |t| *t == token::Eq) => {
                 p.bump();
@@ -156,6 +149,10 @@ fn parse_args<'a>(ecx: &ExtCtxt<'a>, sp: Span, tts: TokenStream) -> PResult<'a,
             }
         }
     }
+
+    // Only allow implicit captures for direct literals
+    let is_direct_literal = matches!(fmtstr.kind, ExprKind::Lit(_));
+
     Ok(MacroInput { fmtstr, args, is_direct_literal })
 }
 

compiler/rustc_codegen_ssa/messages.ftl

@@ -223,8 +223,6 @@ codegen_ssa_multiple_main_functions = entry symbol `main` declared multiple time
 
 codegen_ssa_no_field = no field `{$name}`
 
-codegen_ssa_no_mangle_nameless = `#[no_mangle]` cannot be used on {$definition} as it has no name
-
 codegen_ssa_no_module_named =
     no module named `{$user_path}` (mangled: {$cgu_name}). available modules: {$cgu_names}
 

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -19,7 +19,6 @@ use rustc_span::{Ident, Span, sym};
 use rustc_target::spec::SanitizerSet;
 
 use crate::errors;
-use crate::errors::NoMangleNameless;
 use crate::target_features::{
     check_target_feature_trait_unsafe, check_tied_features, from_target_feature_attr,
 };
@@ -182,14 +181,10 @@ fn process_builtin_attrs(
                     if tcx.opt_item_name(did.to_def_id()).is_some() {
                         codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
                     } else {
-                        tcx.dcx().emit_err(NoMangleNameless {
-                            span: *attr_span,
-                            definition: format!(
-                                "{} {}",
-                                tcx.def_descr_article(did.to_def_id()),
-                                tcx.def_descr(did.to_def_id())
-                            ),
-                        });
+                        tcx.dcx().span_delayed_bug(
+                            *attr_span,
+                            "no_mangle should be on a named function",
+                        );
                     }
                 }
                 AttributeKind::Optimize(optimize, _) => codegen_fn_attrs.optimize = *optimize,

compiler/rustc_codegen_ssa/src/errors.rs

@@ -1284,14 +1284,6 @@ impl<G: EmissionGuarantee> Diagnostic<'_, G> for TargetFeatureDisableOrEnable<'_
     }
 }
 
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_no_mangle_nameless)]
-pub(crate) struct NoMangleNameless {
-    #[primary_span]
-    pub span: Span,
-    pub definition: String,
-}
-
 #[derive(Diagnostic)]
 #[diag(codegen_ssa_feature_not_valid)]
 pub(crate) struct FeatureNotValid<'a> {

compiler/rustc_hir_typeck/src/pat.rs

@@ -3115,20 +3115,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // binding mode. This keeps it from making those suggestions, as doing so could panic.
         let info = table.entry(pat_id).or_insert_with(|| ty::Rust2024IncompatiblePatInfo {
             primary_labels: Vec::new(),
-            bad_modifiers: false,
+            bad_ref_modifiers: false,
+            bad_mut_modifiers: false,
             bad_ref_pats: false,
             suggest_eliding_modes: !self.tcx.features().ref_pat_eat_one_layer_2024()
                 && !self.tcx.features().ref_pat_eat_one_layer_2024_structural(),
         });
 
         let pat_kind = if let PatKind::Binding(user_bind_annot, _, _, _) = subpat.kind {
-            info.bad_modifiers = true;
             // If the user-provided binding modifier doesn't match the default binding mode, we'll
             // need to suggest reference patterns, which can affect other bindings.
             // For simplicity, we opt to suggest making the pattern fully explicit.
             info.suggest_eliding_modes &=
                 user_bind_annot == BindingMode(ByRef::Yes(def_br_mutbl), Mutability::Not);
-            "binding modifier"
+            if user_bind_annot == BindingMode(ByRef::No, Mutability::Mut) {
+                info.bad_mut_modifiers = true;
+                "`mut` binding modifier"
+            } else {
+                info.bad_ref_modifiers = true;
+                match user_bind_annot.1 {
+                    Mutability::Not => "explicit `ref` binding modifier",
+                    Mutability::Mut => "explicit `ref mut` binding modifier",
+                }
+            }
         } else {
             info.bad_ref_pats = true;
             // For simplicity, we don't try to suggest eliding reference patterns. Thus, we'll
@@ -3147,11 +3156,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // so, we may want to inspect the span's source callee or macro backtrace.
             "occurs within macro expansion".to_owned()
         } else {
-            let dbm_str = match def_br_mutbl {
-                Mutability::Not => "ref",
-                Mutability::Mut => "ref mut",
-            };
-            format!("{pat_kind} not allowed under `{dbm_str}` default binding mode")
+            format!("{pat_kind} not allowed when implicitly borrowing")
         };
         info.primary_labels.push((trimmed_span, primary_label));
     }

compiler/rustc_lint_defs/src/builtin.rs

@@ -1601,7 +1601,7 @@ declare_lint! {
     "detects patterns whose meaning will change in Rust 2024",
     @future_incompatible = FutureIncompatibleInfo {
         reason: FutureIncompatibilityReason::EditionSemanticsChange(Edition::Edition2024),
-        reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>",
+        reference: "<https://doc.rust-lang.org/edition-guide/rust-2024/match-ergonomics.html>",
     };
 }
 

compiler/rustc_middle/src/ty/typeck_results.rs

@@ -858,8 +858,10 @@ impl<'tcx> std::fmt::Display for UserTypeKind<'tcx> {
 pub struct Rust2024IncompatiblePatInfo {
     /// Labeled spans for `&`s, `&mut`s, and binding modifiers incompatible with Rust 2024.
     pub primary_labels: Vec<(Span, String)>,
-    /// Whether any binding modifiers occur under a non-`move` default binding mode.
-    pub bad_modifiers: bool,
+    /// Whether any `mut` binding modifiers occur under a non-`move` default binding mode.
+    pub bad_mut_modifiers: bool,
+    /// Whether any `ref`/`ref mut` binding modifiers occur under a non-`move` default binding mode.
+    pub bad_ref_modifiers: bool,
     /// Whether any `&` or `&mut` patterns occur under a non-`move` default binding mode.
     pub bad_ref_pats: bool,
     /// If `true`, we can give a simpler suggestion solely by eliding explicit binding modifiers.

compiler/rustc_mir_build/messages.ftl

@@ -322,17 +322,6 @@ mir_build_pointer_pattern = function pointers and raw pointers not derived from
 
 mir_build_privately_uninhabited = pattern `{$witness_1}` is currently uninhabited, but this variant contains private fields which may become inhabited in the future
 
-mir_build_rust_2024_incompatible_pat = {$bad_modifiers ->
-        *[true] binding modifiers{$bad_ref_pats ->
-            *[true] {" "}and reference patterns
-            [false] {""}
-        }
-        [false] reference patterns
-    } may only be written when the default binding mode is `move`{$is_hard_error ->
-        *[true] {""}
-        [false] {" "}in Rust 2024
-    }
-
 mir_build_static_in_pattern = statics cannot be referenced in patterns
     .label = can't be used in patterns
 mir_build_static_in_pattern_def = `static` defined here

compiler/rustc_mir_build/src/errors.rs

@@ -1,8 +1,7 @@
-use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, EmissionGuarantee, Level,
-    MultiSpan, Subdiagnostic, pluralize,
+    MultiSpan, Subdiagnostic,
 };
 use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::{self, Ty};
@@ -1087,69 +1086,6 @@ pub(crate) enum MiscPatternSuggestion {
     },
 }
 
-#[derive(LintDiagnostic)]
-#[diag(mir_build_rust_2024_incompatible_pat)]
-pub(crate) struct Rust2024IncompatiblePat {
-    #[subdiagnostic]
-    pub(crate) sugg: Rust2024IncompatiblePatSugg,
-    pub(crate) bad_modifiers: bool,
-    pub(crate) bad_ref_pats: bool,
-    pub(crate) is_hard_error: bool,
-}
-
-pub(crate) struct Rust2024IncompatiblePatSugg {
-    /// If true, our suggestion is to elide explicit binding modifiers.
-    /// If false, our suggestion is to make the pattern fully explicit.
-    pub(crate) suggest_eliding_modes: bool,
-    pub(crate) suggestion: Vec<(Span, String)>,
-    pub(crate) ref_pattern_count: usize,
-    pub(crate) binding_mode_count: usize,
-    /// Labels for where incompatibility-causing by-ref default binding modes were introduced.
-    pub(crate) default_mode_labels: FxIndexMap<Span, ty::Mutability>,
-}
-
-impl Subdiagnostic for Rust2024IncompatiblePatSugg {
-    fn add_to_diag<G: EmissionGuarantee>(self, diag: &mut Diag<'_, G>) {
-        // Format and emit explanatory notes about default binding modes. Reversing the spans' order
-        // means if we have nested spans, the innermost ones will be visited first.
-        for (span, def_br_mutbl) in self.default_mode_labels.into_iter().rev() {
-            // Don't point to a macro call site.
-            if !span.from_expansion() {
-                let note_msg = "matching on a reference type with a non-reference pattern changes the default binding mode";
-                let label_msg =
-                    format!("this matches on type `{}_`", def_br_mutbl.ref_prefix_str());
-                let mut label = MultiSpan::from(span);
-                label.push_span_label(span, label_msg);
-                diag.span_note(label, note_msg);
-            }
-        }
-
-        // Format and emit the suggestion.
-        let applicability =
-            if self.suggestion.iter().all(|(span, _)| span.can_be_used_for_suggestions()) {
-                Applicability::MachineApplicable
-            } else {
-                Applicability::MaybeIncorrect
-            };
-        let msg = if self.suggest_eliding_modes {
-            let plural_modes = pluralize!(self.binding_mode_count);
-            format!("remove the unnecessary binding modifier{plural_modes}")
-        } else {
-            let plural_derefs = pluralize!(self.ref_pattern_count);
-            let and_modes = if self.binding_mode_count > 0 {
-                format!(" and variable binding mode{}", pluralize!(self.binding_mode_count))
-            } else {
-                String::new()
-            };
-            format!("make the implied reference pattern{plural_derefs}{and_modes} explicit")
-        };
-        // FIXME(dianne): for peace of mind, don't risk emitting a 0-part suggestion (that panics!)
-        if !self.suggestion.is_empty() {
-            diag.multipart_suggestion_verbose(msg, self.suggestion, applicability);
-        }
-    }
-}
-
 #[derive(Diagnostic)]
 #[diag(mir_build_loop_match_invalid_update)]
 pub(crate) struct LoopMatchInvalidUpdate {