Auto merge of #142794 - tgross35:rollup-iae7okj, r=tgross35

Rollup of 9 pull requests

Successful merges:

 - rust-lang/rust#142331 (Add `trim_prefix` and `trim_suffix` methods for both `slice` and `str` types.)
 - rust-lang/rust#142491 (Rework #[cold] attribute parser)
 - rust-lang/rust#142494 (Fix missing docs in `rustc_attr_parsing`)
 - rust-lang/rust#142495 (Better template for `#[repr]` attributes)
 - rust-lang/rust#142497 (Fix random failure when JS code is executed when the whole file was not read yet)
 - rust-lang/rust#142575 (Ensure copy* intrinsics also perform the static self-init checks)
 - rust-lang/rust#142650 (Refactor Translator)
 - rust-lang/rust#142713 (mbe: Refactor transcription)
 - rust-lang/rust#142755 (rustdoc: Remove `FormatRenderer::cache`)

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

5 files changed, 56 insertions, 2 deletions

diff --git a/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs b/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
index ddcf82cbf7c..1b03525a5ce 100644
--- a/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
@@ -38,3 +38,21 @@ impl<S: Stage> SingleAttributeParser<S> for OptimizeParser {
         Some(AttributeKind::Optimize(res, cx.attr_span))
     }
 }
+
+pub(crate) struct ColdParser;
+
+impl<S: Stage> SingleAttributeParser<S> for ColdParser {
+    const PATH: &[rustc_span::Symbol] = &[sym::cold];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const TEMPLATE: AttributeTemplate = template!(Word);
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        if !args.no_args() {
+            cx.expected_no_args(args.span().unwrap_or(cx.attr_span));
+            return None;
+        };
+
+        Some(AttributeKind::Cold(cx.attr_span))
+    }
+}
diff --git a/compiler/rustc_attr_parsing/src/attributes/mod.rs b/compiler/rustc_attr_parsing/src/attributes/mod.rs
index 3bb4c163d32..78a696afa27 100644
--- a/compiler/rustc_attr_parsing/src/attributes/mod.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/mod.rs
@@ -87,8 +87,19 @@ pub(crate) trait AttributeParser<S: Stage>: Default + 'static {
 /// [`SingleAttributeParser`] can only convert attributes one-to-one, and cannot combine multiple
 /// attributes together like is necessary for `#[stable()]` and `#[unstable()]` for example.
 pub(crate) trait SingleAttributeParser<S: Stage>: 'static {
+    /// The single path of the attribute this parser accepts.
+    ///
+    /// If you need the parser to accept more than one path, use [`AttributeParser`] instead
     const PATH: &[Symbol];
+
+    /// Configures the precedence of attributes with the same `PATH` on a syntax node.
     const ATTRIBUTE_ORDER: AttributeOrder;
+
+    /// Configures what to do when when the same attribute is
+    /// applied more than once on the same syntax node.
+    ///
+    /// [`ATTRIBUTE_ORDER`](Self::ATTRIBUTE_ORDER) specified which one is assumed to be correct,
+    /// and this specified whether to, for example, warn or error on the other one.
     const ON_DUPLICATE: OnDuplicate<S>;
 
     /// The template this attribute parser should implement. Used for diagnostics.
@@ -98,6 +109,8 @@ pub(crate) trait SingleAttributeParser<S: Stage>: 'static {
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind>;
 }
 
+/// Use in combination with [`SingleAttributeParser`].
+/// `Single<T: SingleAttributeParser>` implements [`AttributeParser`].
 pub(crate) struct Single<T: SingleAttributeParser<S>, S: Stage>(
     PhantomData<(S, T)>,
     Option<(AttributeKind, Span)>,
@@ -230,6 +243,10 @@ pub(crate) trait CombineAttributeParser<S: Stage>: 'static {
     const PATH: &[rustc_span::Symbol];
 
     type Item;
+    /// A function that converts individual items (of type [`Item`](Self::Item)) into the final attribute.
+    ///
+    /// For example, individual representations fomr `#[repr(...)]` attributes into an `AttributeKind::Repr(x)`,
+    ///  where `x` is a vec of these individual reprs.
     const CONVERT: ConvertFn<Self::Item>;
 
     /// The template this attribute parser should implement. Used for diagnostics.
@@ -242,6 +259,8 @@ pub(crate) trait CombineAttributeParser<S: Stage>: 'static {
     ) -> impl IntoIterator<Item = Self::Item> + 'c;
 }
 
+/// Use in combination with [`CombineAttributeParser`].
+/// `Combine<T: CombineAttributeParser>` implements [`AttributeParser`].
 pub(crate) struct Combine<T: CombineAttributeParser<S>, S: Stage>(
     PhantomData<(S, T)>,
     ThinVec<<T as CombineAttributeParser<S>>::Item>,
diff --git a/compiler/rustc_attr_parsing/src/attributes/repr.rs b/compiler/rustc_attr_parsing/src/attributes/repr.rs
index eb16c3f95f0..4aa27043e98 100644
--- a/compiler/rustc_attr_parsing/src/attributes/repr.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/repr.rs
@@ -25,7 +25,8 @@ impl<S: Stage> CombineAttributeParser<S> for ReprParser {
     const PATH: &[Symbol] = &[sym::repr];
     const CONVERT: ConvertFn<Self::Item> = AttributeKind::Repr;
     // FIXME(jdonszelmann): never used
-    const TEMPLATE: AttributeTemplate = template!(List: "C");
+    const TEMPLATE: AttributeTemplate =
+        template!(List: "C | Rust | align(...) | packed(...) | <integer type> | transparent");
 
     fn extend<'c>(
         cx: &'c mut AcceptContext<'_, '_, S>,
diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
index 7925c43d62f..8311fccacd8 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::OptimizeParser;
+use crate::attributes::codegen_attrs::{ColdParser, OptimizeParser};
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::deprecation::DeprecationParser;
 use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
@@ -106,6 +106,7 @@ attribute_parsers!(
 
         // tidy-alphabetical-start
         Single<AsPtrParser>,
+        Single<ColdParser>,
         Single<ConstStabilityIndirectParser>,
         Single<DeprecationParser>,
         Single<InlineParser>,
@@ -234,6 +235,16 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         })
     }
 
+    pub(crate) fn expected_no_args(&self, args_span: Span) -> ErrorGuaranteed {
+        self.emit_err(AttributeParseError {
+            span: args_span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            attribute: self.attr_path.clone(),
+            reason: AttributeParseErrorReason::ExpectedNoArgs,
+        })
+    }
+
     /// emit an error that a `name = value` pair was expected at this span. The symbol can be given for
     /// a nicer error message talking about the specific name that was found lacking a value.
     pub(crate) fn expected_name_value(&self, span: Span, name: Option<Symbol>) -> ErrorGuaranteed {
diff --git a/compiler/rustc_attr_parsing/src/session_diagnostics.rs b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
index 337921a318c..29f2e44a98a 100644
--- a/compiler/rustc_attr_parsing/src/session_diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
@@ -474,6 +474,7 @@ pub(crate) struct UnrecognizedReprHint {
 }
 
 pub(crate) enum AttributeParseErrorReason {
+    ExpectedNoArgs,
     ExpectedStringLiteral { byte_string: Option<Span> },
     ExpectedSingleArgument,
     ExpectedList,
@@ -529,6 +530,10 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
                 diag.span_label(self.span, format!("didn't expect a literal here"));
                 diag.code(E0565);
             }
+            AttributeParseErrorReason::ExpectedNoArgs => {
+                diag.span_label(self.span, format!("didn't expect any arguments here"));
+                diag.code(E0565);
+            }
             AttributeParseErrorReason::ExpectedNameValue(None) => {
                 diag.span_label(
                     self.span,