Auto merge of #142906 - jdonszelmann:rollup-togt1dl, r=jdonszelmann

Rollup of 5 pull requests

Successful merges:

 - rust-lang/rust#142493 (rework `#[naked]` attribute parser)
 - rust-lang/rust#142636 (bootstrap.example.toml: use less contextual format)
 - rust-lang/rust#142822 (Make `PartialEq` a `const_trait`)
 - rust-lang/rust#142892 (Fix ICE on debug builds where lints are delayed on the crate root)
 - rust-lang/rust#142904 (notify me when rdg is touched)

Failed merges:

 - rust-lang/rust#142827 (Move error code explanation removal check into tidy)

r? `@ghost`
`@rustbot` modify labels: rollup

6 files changed, 217 insertions, 34 deletions

diff --git a/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs b/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
index ba4e2935004..24c40c301fe 100644
--- a/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
@@ -1,10 +1,12 @@
 use rustc_attr_data_structures::{AttributeKind, OptimizeAttr};
 use rustc_feature::{AttributeTemplate, template};
-use rustc_span::sym;
+use rustc_session::parse::feature_err;
+use rustc_span::{Span, sym};
 
-use super::{AttributeOrder, OnDuplicate, SingleAttributeParser};
-use crate::context::{AcceptContext, Stage};
+use super::{AcceptMapping, AttributeOrder, AttributeParser, OnDuplicate, SingleAttributeParser};
+use crate::context::{AcceptContext, FinalizeContext, Stage};
 use crate::parser::ArgParser;
+use crate::session_diagnostics::NakedFunctionIncompatibleAttribute;
 
 pub(crate) struct OptimizeParser;
 
@@ -51,12 +53,119 @@ impl<S: Stage> SingleAttributeParser<S> for ColdParser {
         if !args.no_args() {
             cx.expected_no_args(args.span().unwrap_or(cx.attr_span));
             return None;
-        };
+        }
 
         Some(AttributeKind::Cold(cx.attr_span))
     }
 }
 
+#[derive(Default)]
+pub(crate) struct NakedParser {
+    span: Option<Span>,
+}
+
+impl<S: Stage> AttributeParser<S> for NakedParser {
+    const ATTRIBUTES: AcceptMapping<Self, S> =
+        &[(&[sym::naked], template!(Word), |this, cx, args| {
+            if !args.no_args() {
+                cx.expected_no_args(args.span().unwrap_or(cx.attr_span));
+                return;
+            }
+
+            if let Some(earlier) = this.span {
+                let span = cx.attr_span;
+                cx.warn_unused_duplicate(earlier, span);
+            } else {
+                this.span = Some(cx.attr_span);
+            }
+        })];
+
+    fn finalize(self, cx: &FinalizeContext<'_, '_, S>) -> Option<AttributeKind> {
+        // FIXME(jdonszelmann): upgrade this list to *parsed* attributes
+        // once all of these have parsed forms. That'd make the check much nicer...
+        //
+        // many attributes don't make sense in combination with #[naked].
+        // Notable attributes that are incompatible with `#[naked]` are:
+        //
+        // * `#[inline]`
+        // * `#[track_caller]`
+        // * `#[test]`, `#[ignore]`, `#[should_panic]`
+        //
+        // NOTE: when making changes to this list, check that `error_codes/E0736.md` remains
+        // accurate.
+        const ALLOW_LIST: &[rustc_span::Symbol] = &[
+            // conditional compilation
+            sym::cfg_trace,
+            sym::cfg_attr_trace,
+            // testing (allowed here so better errors can be generated in `rustc_builtin_macros::test`)
+            sym::test,
+            sym::ignore,
+            sym::should_panic,
+            sym::bench,
+            // diagnostics
+            sym::allow,
+            sym::warn,
+            sym::deny,
+            sym::forbid,
+            sym::deprecated,
+            sym::must_use,
+            // abi, linking and FFI
+            sym::cold,
+            sym::export_name,
+            sym::link_section,
+            sym::linkage,
+            sym::no_mangle,
+            sym::instruction_set,
+            sym::repr,
+            sym::rustc_std_internal_symbol,
+            sym::align,
+            // obviously compatible with self
+            sym::naked,
+            // documentation
+            sym::doc,
+        ];
+
+        let span = self.span?;
+
+        // only if we found a naked attribute do we do the somewhat expensive check
+        'outer: for other_attr in cx.all_attrs {
+            for allowed_attr in ALLOW_LIST {
+                if other_attr.segments().next().is_some_and(|i| cx.tools.contains(&i.name)) {
+                    // effectively skips the error message  being emitted below
+                    // if it's a tool attribute
+                    continue 'outer;
+                }
+                if other_attr.word_is(*allowed_attr) {
+                    // effectively skips the error message  being emitted below
+                    // if its an allowed attribute
+                    continue 'outer;
+                }
+
+                if other_attr.word_is(sym::target_feature) {
+                    if !cx.features().naked_functions_target_feature() {
+                        feature_err(
+                            &cx.sess(),
+                            sym::naked_functions_target_feature,
+                            other_attr.span(),
+                            "`#[target_feature(/* ... */)]` is currently unstable on `#[naked]` functions",
+                        ).emit();
+                    }
+
+                    continue 'outer;
+                }
+            }
+
+            cx.emit_err(NakedFunctionIncompatibleAttribute {
+                span: other_attr.span(),
+                naked_span: span,
+                attr: other_attr.get_attribute_path().to_string(),
+            });
+        }
+
+        Some(AttributeKind::Naked(span))
+    }
+}
+
 pub(crate) struct NoMangleParser;
 
 impl<S: Stage> SingleAttributeParser<S> for NoMangleParser {
diff --git a/compiler/rustc_attr_parsing/src/attributes/inline.rs b/compiler/rustc_attr_parsing/src/attributes/inline.rs
index 25efc3ae49b..11844f4cd95 100644
--- a/compiler/rustc_attr_parsing/src/attributes/inline.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/inline.rs
@@ -45,10 +45,8 @@ impl<S: Stage> SingleAttributeParser<S> for InlineParser {
             ArgParser::NameValue(_) => {
                 let suggestions =
                     <Self as SingleAttributeParser<S>>::TEMPLATE.suggestions(false, "inline");
-                cx.emit_lint(
-                    AttributeLintKind::IllFormedAttributeInput { suggestions },
-                    cx.attr_span,
-                );
+                let span = cx.attr_span;
+                cx.emit_lint(AttributeLintKind::IllFormedAttributeInput { suggestions }, span);
                 return None;
             }
         }
diff --git a/compiler/rustc_attr_parsing/src/attributes/mod.rs b/compiler/rustc_attr_parsing/src/attributes/mod.rs
index 3162c1fc727..738d8735b69 100644
--- a/compiler/rustc_attr_parsing/src/attributes/mod.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/mod.rs
@@ -17,7 +17,6 @@
 use std::marker::PhantomData;
 
 use rustc_attr_data_structures::AttributeKind;
-use rustc_attr_data_structures::lints::AttributeLintKind;
 use rustc_feature::AttributeTemplate;
 use rustc_span::{Span, Symbol};
 use thin_vec::ThinVec;
@@ -189,14 +188,8 @@ impl<S: Stage> OnDuplicate<S> {
         unused: Span,
     ) {
         match self {
-            OnDuplicate::Warn => cx.emit_lint(
-                AttributeLintKind::UnusedDuplicate { this: unused, other: used, warning: false },
-                unused,
-            ),
-            OnDuplicate::WarnButFutureError => cx.emit_lint(
-                AttributeLintKind::UnusedDuplicate { this: unused, other: used, warning: true },
-                unused,
-            ),
+            OnDuplicate::Warn => cx.warn_unused_duplicate(used, unused),
+            OnDuplicate::WarnButFutureError => cx.warn_unused_duplicate_future_error(used, unused),
             OnDuplicate::Error => {
                 cx.emit_err(UnusedMultiple {
                     this: used,
diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
index 171995dc9cb..457e073c488 100644
--- a/compiler/rustc_attr_parsing/src/context.rs
+++ b/compiler/rustc_attr_parsing/src/context.rs
@@ -15,7 +15,7 @@ use rustc_session::Session;
 use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span, Symbol, sym};
 
 use crate::attributes::allow_unstable::{AllowConstFnUnstableParser, AllowInternalUnstableParser};
-use crate::attributes::codegen_attrs::{ColdParser, NoMangleParser, OptimizeParser};
+use crate::attributes::codegen_attrs::{ColdParser, NakedParser, NoMangleParser, OptimizeParser};
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::deprecation::DeprecationParser;
 use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
@@ -28,7 +28,7 @@ use crate::attributes::stability::{
 };
 use crate::attributes::transparency::TransparencyParser;
 use crate::attributes::{AttributeParser as _, Combine, Single};
-use crate::parser::{ArgParser, MetaItemParser};
+use crate::parser::{ArgParser, MetaItemParser, PathParser};
 use crate::session_diagnostics::{AttributeParseError, AttributeParseErrorReason, UnknownMetaItem};
 
 macro_rules! group_type {
@@ -97,6 +97,7 @@ attribute_parsers!(
         BodyStabilityParser,
         ConfusablesParser,
         ConstStabilityParser,
+        NakedParser,
         StabilityParser,
         // tidy-alphabetical-end
 
@@ -174,7 +175,7 @@ pub struct Late;
 ///
 /// Gives [`AttributeParser`]s enough information to create errors, for example.
 pub(crate) struct AcceptContext<'f, 'sess, S: Stage> {
-    pub(crate) finalize_cx: FinalizeContext<'f, 'sess, S>,
+    pub(crate) shared: SharedContext<'f, 'sess, S>,
     /// The span of the attribute currently being parsed
     pub(crate) attr_span: Span,
 
@@ -187,7 +188,7 @@ pub(crate) struct AcceptContext<'f, 'sess, S: Stage> {
     pub(crate) attr_path: AttrPath,
 }
 
-impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
+impl<'f, 'sess: 'f, S: Stage> SharedContext<'f, 'sess, S> {
     pub(crate) fn emit_err(&self, diag: impl for<'x> Diagnostic<'x>) -> ErrorGuaranteed {
         S::emit_err(&self.sess, diag)
     }
@@ -200,6 +201,34 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         (self.emit_lint)(AttributeLint { id, span, kind: lint });
     }
 
+    pub(crate) fn warn_unused_duplicate(&mut self, used_span: Span, unused_span: Span) {
+        self.emit_lint(
+            AttributeLintKind::UnusedDuplicate {
+                this: unused_span,
+                other: used_span,
+                warning: false,
+            },
+            unused_span,
+        )
+    }
+
+    pub(crate) fn warn_unused_duplicate_future_error(
+        &mut self,
+        used_span: Span,
+        unused_span: Span,
+    ) {
+        self.emit_lint(
+            AttributeLintKind::UnusedDuplicate {
+                this: unused_span,
+                other: used_span,
+                warning: true,
+            },
+            unused_span,
+        )
+    }
+}
+
+impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
     pub(crate) fn unknown_key(
         &self,
         span: Span,
@@ -332,16 +361,16 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
 }
 
 impl<'f, 'sess, S: Stage> Deref for AcceptContext<'f, 'sess, S> {
-    type Target = FinalizeContext<'f, 'sess, S>;
+    type Target = SharedContext<'f, 'sess, S>;
 
     fn deref(&self) -> &Self::Target {
-        &self.finalize_cx
+        &self.shared
     }
 }
 
 impl<'f, 'sess, S: Stage> DerefMut for AcceptContext<'f, 'sess, S> {
     fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.finalize_cx
+        &mut self.shared
     }
 }
 
@@ -349,7 +378,7 @@ impl<'f, 'sess, S: Stage> DerefMut for AcceptContext<'f, 'sess, S> {
 ///
 /// Gives [`AttributeParser`](crate::attributes::AttributeParser)s enough information to create
 /// errors, for example.
-pub(crate) struct FinalizeContext<'p, 'sess, S: Stage> {
+pub(crate) struct SharedContext<'p, 'sess, S: Stage> {
     /// The parse context, gives access to the session and the
     /// diagnostics context.
     pub(crate) cx: &'p mut AttributeParser<'sess, S>,
@@ -358,10 +387,40 @@ pub(crate) struct FinalizeContext<'p, 'sess, S: Stage> {
     /// The id ([`NodeId`] if `S` is `Early`, [`HirId`] if `S` is `Late`) of the syntactical component this attribute was applied to
     pub(crate) target_id: S::Id,
 
-    pub(crate) emit_lint: &'p mut dyn FnMut(AttributeLint<S::Id>),
+    emit_lint: &'p mut dyn FnMut(AttributeLint<S::Id>),
+}
+
+/// Context given to every attribute parser during finalization.
+///
+/// Gives [`AttributeParser`](crate::attributes::AttributeParser)s enough information to create
+/// errors, for example.
+pub(crate) struct FinalizeContext<'p, 'sess, S: Stage> {
+    pub(crate) shared: SharedContext<'p, 'sess, S>,
+
+    /// A list of all attribute on this syntax node.
+    ///
+    /// Useful for compatibility checks with other attributes in [`finalize`](crate::attributes::AttributeParser::finalize)
+    ///
+    /// Usually, you should use normal attribute parsing logic instead,
+    /// especially when making a *denylist* of other attributes.
+    pub(crate) all_attrs: &'p [PathParser<'p>],
 }
 
 impl<'p, 'sess: 'p, S: Stage> Deref for FinalizeContext<'p, 'sess, S> {
+    type Target = SharedContext<'p, 'sess, S>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.shared
+    }
+}
+
+impl<'p, 'sess: 'p, S: Stage> DerefMut for FinalizeContext<'p, 'sess, S> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.shared
+    }
+}
+
+impl<'p, 'sess: 'p, S: Stage> Deref for SharedContext<'p, 'sess, S> {
     type Target = AttributeParser<'sess, S>;
 
     fn deref(&self) -> &Self::Target {
@@ -369,7 +428,7 @@ impl<'p, 'sess: 'p, S: Stage> Deref for FinalizeContext<'p, 'sess, S> {
     }
 }
 
-impl<'p, 'sess: 'p, S: Stage> DerefMut for FinalizeContext<'p, 'sess, S> {
+impl<'p, 'sess: 'p, S: Stage> DerefMut for SharedContext<'p, 'sess, S> {
     fn deref_mut(&mut self) -> &mut Self::Target {
         self.cx
     }
@@ -384,8 +443,7 @@ pub enum OmitDoc {
 /// Context created once, for example as part of the ast lowering
 /// context, through which all attributes can be lowered.
 pub struct AttributeParser<'sess, S: Stage = Late> {
-    #[expect(dead_code)] // FIXME(jdonszelmann): needed later to verify we parsed all attributes
-    tools: Vec<Symbol>,
+    pub(crate) tools: Vec<Symbol>,
     features: Option<&'sess Features>,
     sess: &'sess Session,
     stage: PhantomData<S>,
@@ -473,6 +531,7 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
         mut emit_lint: impl FnMut(AttributeLint<S::Id>),
     ) -> Vec<Attribute> {
         let mut attributes = Vec::new();
+        let mut attr_paths = Vec::new();
 
         for attr in attrs {
             // If we're only looking for a single attribute, skip all the ones we don't care about.
@@ -516,6 +575,8 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
                 //     }))
                 // }
                 ast::AttrKind::Normal(n) => {
+                    attr_paths.push(PathParser::Ast(&n.item.path));
+
                     let parser = MetaItemParser::from_attr(n, self.dcx());
                     let path = parser.path();
                     let args = parser.args();
@@ -524,7 +585,7 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
                     if let Some(accepts) = S::parsers().0.get(parts.as_slice()) {
                         for (template, accept) in accepts {
                             let mut cx: AcceptContext<'_, 'sess, S> = AcceptContext {
-                                finalize_cx: FinalizeContext {
+                                shared: SharedContext {
                                     cx: self,
                                     target_span,
                                     target_id,
@@ -568,10 +629,13 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
         let mut parsed_attributes = Vec::new();
         for f in &S::parsers().1 {
             if let Some(attr) = f(&mut FinalizeContext {
-                cx: self,
-                target_span,
-                target_id,
-                emit_lint: &mut emit_lint,
+                shared: SharedContext {
+                    cx: self,
+                    target_span,
+                    target_id,
+                    emit_lint: &mut emit_lint,
+                },
+                all_attrs: &attr_paths,
             }) {
                 parsed_attributes.push(Attribute::Parsed(attr));
             }
diff --git a/compiler/rustc_attr_parsing/src/parser.rs b/compiler/rustc_attr_parsing/src/parser.rs
index 1edbe3a9d27..e02dc098127 100644
--- a/compiler/rustc_attr_parsing/src/parser.rs
+++ b/compiler/rustc_attr_parsing/src/parser.rs
@@ -87,6 +87,14 @@ impl<'a> PathParser<'a> {
     pub fn word_is(&self, sym: Symbol) -> bool {
         self.word().map(|i| i.name == sym).unwrap_or(false)
     }
+
+    /// Checks whether the first segments match the givens.
+    ///
+    /// Unlike [`segments_is`](Self::segments_is),
+    /// `self` may contain more segments than the number matched  against.
+    pub fn starts_with(&self, segments: &[Symbol]) -> bool {
+        segments.len() < self.len() && self.segments().zip(segments).all(|(a, b)| a.name == *b)
+    }
 }
 
 impl Display for PathParser<'_> {
diff --git a/compiler/rustc_attr_parsing/src/session_diagnostics.rs b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
index 2a020770e5d..808e452799d 100644
--- a/compiler/rustc_attr_parsing/src/session_diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
@@ -482,6 +482,17 @@ pub(crate) struct UnrecognizedReprHint {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(attr_parsing_naked_functions_incompatible_attribute, code = E0736)]
+pub(crate) struct NakedFunctionIncompatibleAttribute {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[label(attr_parsing_naked_attribute)]
+    pub naked_span: Span,
+    pub attr: String,
+}
+
 pub(crate) enum AttributeParseErrorReason {
     ExpectedNoArgs,
     ExpectedStringLiteral { byte_string: Option<Span> },