Auto merge of #120620 - matthiaskrgr:rollup-sscmbsm, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - #119543 (add avx512fp16 to x86 target features)
 - #120004 (Release notes for 1.76)
 - #120562 (Revert unsound libcore changes)
 - #120566 (coverage: Use normal `edition:` headers in coverage tests)
 - #120570 (Suggest changing type to const parameters if we encounter a type in the trait bound position)
 - #120571 (Miscellaneous diagnostics cleanups)
 - #120573 (Remove `BorrowckErrors::tainted_by_errors`)
 - #120592 (Remove unnecessary `.to_string()`/`.as_str()`s)
 - #120610 (hir: Remove the generic type parameter from `MaybeOwned`)
 - #120616 (Fix ICE on field access on a tainted type after const-eval failure)

Failed merges:

 - #120569 (coverage: Improve handling of function/closure spans)

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

6 files changed, 60 insertions, 97 deletions

diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index b87eef07fd5..8ad4925cff2 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -33,7 +33,10 @@ pub type DiagnosticArgName = Cow<'static, str>;
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Encodable, Decodable)]
 pub enum DiagnosticArgValue {
     Str(Cow<'static, str>),
-    Number(i128),
+    // This gets converted to a `FluentNumber`, which is an `f64`. An `i32`
+    // safely fits in an `f64`. Any integers bigger than that will be converted
+    // to strings in `into_diagnostic_arg` and stored using the `Str` variant.
+    Number(i32),
     StrListSepByAnd(Vec<Cow<'static, str>>),
 }
 
@@ -113,7 +116,7 @@ pub struct Diagnostic {
 
     /// With `-Ztrack_diagnostics` enabled,
     /// we print where in rustc this error was emitted.
-    pub emitted_at: DiagnosticLocation,
+    pub(crate) emitted_at: DiagnosticLocation,
 }
 
 #[derive(Clone, Debug, Encodable, Decodable)]
@@ -162,10 +165,10 @@ impl DiagnosticStyledString {
         DiagnosticStyledString(vec![])
     }
     pub fn push_normal<S: Into<String>>(&mut self, t: S) {
-        self.0.push(StringPart::Normal(t.into()));
+        self.0.push(StringPart::normal(t));
     }
     pub fn push_highlighted<S: Into<String>>(&mut self, t: S) {
-        self.0.push(StringPart::Highlighted(t.into()));
+        self.0.push(StringPart::highlighted(t));
     }
     pub fn push<S: Into<String>>(&mut self, t: S, highlight: bool) {
         if highlight {
@@ -175,35 +178,34 @@ impl DiagnosticStyledString {
         }
     }
     pub fn normal<S: Into<String>>(t: S) -> DiagnosticStyledString {
-        DiagnosticStyledString(vec![StringPart::Normal(t.into())])
+        DiagnosticStyledString(vec![StringPart::normal(t)])
     }
 
     pub fn highlighted<S: Into<String>>(t: S) -> DiagnosticStyledString {
-        DiagnosticStyledString(vec![StringPart::Highlighted(t.into())])
+        DiagnosticStyledString(vec![StringPart::highlighted(t)])
     }
 
     pub fn content(&self) -> String {
-        self.0.iter().map(|x| x.content()).collect::<String>()
+        self.0.iter().map(|x| x.content.as_str()).collect::<String>()
     }
 }
 
 #[derive(Debug, PartialEq, Eq)]
-pub enum StringPart {
-    Normal(String),
-    Highlighted(String),
+pub struct StringPart {
+    content: String,
+    style: Style,
 }
 
 impl StringPart {
-    pub fn content(&self) -> &str {
-        match self {
-            &StringPart::Normal(ref s) | &StringPart::Highlighted(ref s) => s,
-        }
+    pub fn normal<S: Into<String>>(content: S) -> StringPart {
+        StringPart { content: content.into(), style: Style::NoStyle }
+    }
+
+    pub fn highlighted<S: Into<String>>(content: S) -> StringPart {
+        StringPart { content: content.into(), style: Style::Highlight }
     }
 }
 
-// Note: most of these methods are setters that return `&mut Self`. The small
-// number of simple getter functions all have `get_` prefixes to distinguish
-// them from the setters.
 impl Diagnostic {
     #[track_caller]
     pub fn new<M: Into<DiagnosticMessage>>(level: Level, message: M) -> Self {
@@ -389,19 +391,16 @@ impl Diagnostic {
         } else {
             (0, found_label.len() - expected_label.len())
         };
-        let mut msg: Vec<_> =
-            vec![(format!("{}{} `", " ".repeat(expected_padding), expected_label), Style::NoStyle)];
-        msg.extend(expected.0.iter().map(|x| match *x {
-            StringPart::Normal(ref s) => (s.to_owned(), Style::NoStyle),
-            StringPart::Highlighted(ref s) => (s.to_owned(), Style::Highlight),
-        }));
-        msg.push((format!("`{expected_extra}\n"), Style::NoStyle));
-        msg.push((format!("{}{} `", " ".repeat(found_padding), found_label), Style::NoStyle));
-        msg.extend(found.0.iter().map(|x| match *x {
-            StringPart::Normal(ref s) => (s.to_owned(), Style::NoStyle),
-            StringPart::Highlighted(ref s) => (s.to_owned(), Style::Highlight),
-        }));
-        msg.push((format!("`{found_extra}"), Style::NoStyle));
+        let mut msg = vec![StringPart::normal(format!(
+            "{}{} `",
+            " ".repeat(expected_padding),
+            expected_label
+        ))];
+        msg.extend(expected.0.into_iter());
+        msg.push(StringPart::normal(format!("`{expected_extra}\n")));
+        msg.push(StringPart::normal(format!("{}{} `", " ".repeat(found_padding), found_label)));
+        msg.extend(found.0.into_iter());
+        msg.push(StringPart::normal(format!("`{found_extra}")));
 
         // For now, just attach these as notes.
         self.highlighted_note(msg);
@@ -410,9 +409,9 @@ impl Diagnostic {
 
     pub fn note_trait_signature(&mut self, name: Symbol, signature: String) -> &mut Self {
         self.highlighted_note(vec![
-            (format!("`{name}` from trait: `"), Style::NoStyle),
-            (signature, Style::Highlight),
-            ("`".to_string(), Style::NoStyle),
+            StringPart::normal(format!("`{name}` from trait: `")),
+            StringPart::highlighted(signature),
+            StringPart::normal("`"),
         ]);
         self
     }
@@ -424,10 +423,7 @@ impl Diagnostic {
         self
     }
 
-    fn highlighted_note<M: Into<SubdiagnosticMessage>>(
-        &mut self,
-        msg: Vec<(M, Style)>,
-    ) -> &mut Self {
+    fn highlighted_note(&mut self, msg: Vec<StringPart>) -> &mut Self {
         self.sub_with_highlights(Level::Note, msg, MultiSpan::new());
         self
     }
@@ -496,7 +492,7 @@ impl Diagnostic {
     }
 
     /// Add a help message attached to this diagnostic with a customizable highlighted message.
-    pub fn highlighted_help(&mut self, msg: Vec<(String, Style)>) -> &mut Self {
+    pub fn highlighted_help(&mut self, msg: Vec<StringPart>) -> &mut Self {
         self.sub_with_highlights(Level::Help, msg, MultiSpan::new());
         self
     }
@@ -890,15 +886,6 @@ impl Diagnostic {
         self
     }
 
-    pub fn clear_code(&mut self) -> &mut Self {
-        self.code = None;
-        self
-    }
-
-    pub fn get_code(&self) -> Option<ErrCode> {
-        self.code
-    }
-
     pub fn primary_message(&mut self, msg: impl Into<DiagnosticMessage>) -> &mut Self {
         self.messages[0] = (msg.into(), Style::NoStyle);
         self
@@ -913,7 +900,7 @@ impl Diagnostic {
 
     pub fn arg(
         &mut self,
-        name: impl Into<Cow<'static, str>>,
+        name: impl Into<DiagnosticArgName>,
         arg: impl IntoDiagnosticArg,
     ) -> &mut Self {
         self.args.insert(name.into(), arg.into_diagnostic_arg());
@@ -924,10 +911,6 @@ impl Diagnostic {
         self.args = args;
     }
 
-    pub fn messages(&self) -> &[(DiagnosticMessage, Style)] {
-        &self.messages
-    }
-
     /// Helper function that takes a `SubdiagnosticMessage` and returns a `DiagnosticMessage` by
     /// combining it with the primary message of the diagnostic (if translatable, otherwise it just
     /// passes the user's string along).
@@ -958,15 +941,10 @@ impl Diagnostic {
 
     /// Convenience function for internal use, clients should use one of the
     /// public methods above.
-    fn sub_with_highlights<M: Into<SubdiagnosticMessage>>(
-        &mut self,
-        level: Level,
-        messages: Vec<(M, Style)>,
-        span: MultiSpan,
-    ) {
+    fn sub_with_highlights(&mut self, level: Level, messages: Vec<StringPart>, span: MultiSpan) {
         let messages = messages
             .into_iter()
-            .map(|m| (self.subdiagnostic_message_to_diagnostic_message(m.0), m.1))
+            .map(|m| (self.subdiagnostic_message_to_diagnostic_message(m.content), m.style))
             .collect();
         let sub = SubDiagnostic { level, messages, span };
         self.children.push(sub);
diff --git a/compiler/rustc_errors/src/diagnostic_builder.rs b/compiler/rustc_errors/src/diagnostic_builder.rs
index 8bfb1816486..faff7f0b526 100644
--- a/compiler/rustc_errors/src/diagnostic_builder.rs
+++ b/compiler/rustc_errors/src/diagnostic_builder.rs
@@ -255,13 +255,8 @@ impl<'a, G: EmissionGuarantee> DiagnosticBuilder<'a, G> {
     /// Stashes diagnostic for possible later improvement in a different,
     /// later stage of the compiler. The diagnostic can be accessed with
     /// the provided `span` and `key` through [`DiagCtxt::steal_diagnostic()`].
-    pub fn stash(self, span: Span, key: StashKey) {
-        self.dcx.stash_diagnostic(span, key, self.into_diagnostic());
-    }
-
-    /// Converts the builder to a `Diagnostic` for later emission.
-    pub fn into_diagnostic(mut self) -> Diagnostic {
-        self.take_diag()
+    pub fn stash(mut self, span: Span, key: StashKey) {
+        self.dcx.stash_diagnostic(span, key, self.take_diag());
     }
 
     /// Delay emission of this diagnostic as a bug.
diff --git a/compiler/rustc_errors/src/diagnostic_impls.rs b/compiler/rustc_errors/src/diagnostic_impls.rs
index faab3fc663a..15effd3cbec 100644
--- a/compiler/rustc_errors/src/diagnostic_impls.rs
+++ b/compiler/rustc_errors/src/diagnostic_impls.rs
@@ -63,12 +63,8 @@ macro_rules! into_diagnostic_arg_for_number {
         $(
             impl IntoDiagnosticArg for $ty {
                 fn into_diagnostic_arg(self) -> DiagnosticArgValue {
-                    // HACK: `FluentNumber` the underline backing struct represent
-                    // numbers using a f64 which can't represent all the i128 numbers
-                    // So in order to be able to use fluent selectors and still
-                    // have all the numbers representable we only convert numbers
-                    // below a certain threshold.
-                    if let Ok(n) = TryInto::<i128>::try_into(self) && n >= -100 && n <= 100 {
+                    // Convert to a string if it won't fit into `Number`.
+                    if let Ok(n) = TryInto::<i32>::try_into(self) {
                         DiagnosticArgValue::Number(n)
                     } else {
                         self.to_string().into_diagnostic_arg()
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 9f76c1dd248..4be5ed923e5 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -558,7 +558,7 @@ impl Emitter for HumanEmitter {
 /// failures of rustc, as witnessed e.g. in issue #89358.
 pub struct SilentEmitter {
     pub fatal_dcx: DiagCtxt,
-    pub fatal_note: Option<String>,
+    pub fatal_note: String,
 }
 
 impl Translate for SilentEmitter {
@@ -576,13 +576,11 @@ impl Emitter for SilentEmitter {
         None
     }
 
-    fn emit_diagnostic(&mut self, d: &Diagnostic) {
-        if d.level == Level::Fatal {
-            let mut d = d.clone();
-            if let Some(ref note) = self.fatal_note {
-                d.note(note.clone());
-            }
-            self.fatal_dcx.emit_diagnostic(d);
+    fn emit_diagnostic(&mut self, diag: &Diagnostic) {
+        if diag.level == Level::Fatal {
+            let mut diag = diag.clone();
+            diag.note(self.fatal_note.clone());
+            self.fatal_dcx.emit_diagnostic(diag);
         }
     }
 }
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 960b68196ff..b2bd4d8eb95 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -34,7 +34,7 @@ extern crate self as rustc_errors;
 pub use codes::*;
 pub use diagnostic::{
     AddToDiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgName,
-    DiagnosticArgValue, DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
+    DiagnosticArgValue, DiagnosticStyledString, IntoDiagnosticArg, StringPart, SubDiagnostic,
 };
 pub use diagnostic_builder::{
     BugAbort, DiagnosticBuilder, EmissionGuarantee, FatalAbort, IntoDiagnostic,
@@ -102,7 +102,6 @@ pub type PResult<'a, T> = Result<T, PErr<'a>>;
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
 
 // `PResult` is used a lot. Make sure it doesn't unintentionally get bigger.
-// (See also the comment on `DiagnosticBuilderInner`'s `diagnostic` field.)
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 rustc_data_structures::static_assert_size!(PResult<'_, ()>, 16);
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
@@ -1039,10 +1038,6 @@ impl DiagCtxt {
         }
     }
 
-    pub fn take_future_breakage_diagnostics(&self) -> Vec<Diagnostic> {
-        std::mem::take(&mut self.inner.borrow_mut().future_breakage_diagnostics)
-    }
-
     pub fn abort_if_errors(&self) {
         let mut inner = self.inner.borrow_mut();
         inner.emit_stashed_diagnostics();
@@ -1150,8 +1145,12 @@ impl DiagCtxt {
         self.inner.borrow_mut().emitter.emit_artifact_notification(path, artifact_type);
     }
 
-    pub fn emit_future_breakage_report(&self, diags: Vec<Diagnostic>) {
-        self.inner.borrow_mut().emitter.emit_future_breakage_report(diags)
+    pub fn emit_future_breakage_report(&self) {
+        let mut inner = self.inner.borrow_mut();
+        let diags = std::mem::take(&mut inner.future_breakage_diagnostics);
+        if !diags.is_empty() {
+            inner.emitter.emit_future_breakage_report(diags);
+        }
     }
 
     pub fn emit_unused_externs(
@@ -1224,9 +1223,8 @@ impl DiagCtxtInner {
     /// Emit all stashed diagnostics.
     fn emit_stashed_diagnostics(&mut self) -> Option<ErrorGuaranteed> {
         let has_errors = self.has_errors();
-        let diags = self.stashed_diagnostics.drain(..).map(|x| x.1).collect::<Vec<_>>();
         let mut reported = None;
-        for diag in diags {
+        for (_, diag) in std::mem::take(&mut self.stashed_diagnostics).into_iter() {
             // Decrement the count tracking the stash; emitting will increment it.
             if diag.is_error() {
                 if diag.is_lint.is_some() {
@@ -1254,7 +1252,7 @@ impl DiagCtxtInner {
         // be stored. Instead, they are buffered until the `LintExpectationId` is replaced by
         // a stable one by the `LintLevelsBuilder`.
         if let Some(LintExpectationId::Unstable { .. }) = diagnostic.level.get_expectation_id() {
-            self.unstable_expect_diagnostics.push(diagnostic.clone());
+            self.unstable_expect_diagnostics.push(diagnostic);
             return None;
         }
 
@@ -1269,16 +1267,14 @@ impl DiagCtxtInner {
             DelayedBug(DelayedBugKind::Normal) => {
                 let backtrace = std::backtrace::Backtrace::capture();
                 self.span_delayed_bugs
-                    .push(DelayedDiagnostic::with_backtrace(diagnostic.clone(), backtrace));
-
+                    .push(DelayedDiagnostic::with_backtrace(diagnostic, backtrace));
                 #[allow(deprecated)]
                 return Some(ErrorGuaranteed::unchecked_claim_error_was_emitted());
             }
             DelayedBug(DelayedBugKind::GoodPath) => {
                 let backtrace = std::backtrace::Backtrace::capture();
                 self.good_path_delayed_bugs
-                    .push(DelayedDiagnostic::with_backtrace(diagnostic.clone(), backtrace));
-
+                    .push(DelayedDiagnostic::with_backtrace(diagnostic, backtrace));
                 return None;
             }
             _ => {}
@@ -1424,7 +1420,7 @@ impl DiagCtxtInner {
                     &mut out,
                     "delayed span bug: {}\n{}\n",
                     bug.inner
-                        .messages()
+                        .messages
                         .iter()
                         .filter_map(|(msg, _)| msg.as_str())
                         .collect::<String>(),
diff --git a/compiler/rustc_errors/src/snippet.rs b/compiler/rustc_errors/src/snippet.rs
index 98eb70b5fce..b55f7853885 100644
--- a/compiler/rustc_errors/src/snippet.rs
+++ b/compiler/rustc_errors/src/snippet.rs
@@ -197,7 +197,7 @@ pub struct StyledString {
     pub style: Style,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, Encodable, Decodable)]
 pub enum Style {
     MainHeaderMsg,
     HeaderMsg,