Merging upstream version 1.75.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

10 files changed, 237 insertions, 188 deletions

diff --git a/compiler/rustc_span/Cargo.toml b/compiler/rustc_span/Cargo.toml
index ee93f74e7..99de91a06 100644
--- a/compiler/rustc_span/Cargo.toml
+++ b/compiler/rustc_span/Cargo.toml
@@ -3,19 +3,18 @@ name = "rustc_span"
 version = "0.0.0"
 edition = "2021"
 
-[lib]
-
 [dependencies]
-rustc_serialize = { path = "../rustc_serialize" }
-rustc_macros = { path = "../rustc_macros" }
+# tidy-alphabetical-start
+indexmap = { version = "2.0.0" }
+md5 = { package = "md-5", version = "0.10.0" }
+rustc_arena = { path = "../rustc_arena" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_index = { path = "../rustc_index" }
-rustc_arena = { path = "../rustc_arena" }
+rustc_macros = { path = "../rustc_macros" }
+rustc_serialize = { path = "../rustc_serialize" }
 scoped-tls = "1.0"
-unicode-width = "0.1.4"
-cfg-if = "1.0"
-tracing = "0.1"
 sha1 = "0.10.0"
 sha2 = "0.10.1"
-md5 = { package = "md-5", version = "0.10.0" }
-indexmap = { version = "2.0.0" }
+tracing = "0.1"
+unicode-width = "0.1.4"
+# tidy-alphabetical-end
diff --git a/compiler/rustc_span/src/analyze_source_file.rs b/compiler/rustc_span/src/analyze_source_file.rs
index 450d5455f..7da7dc610 100644
--- a/compiler/rustc_span/src/analyze_source_file.rs
+++ b/compiler/rustc_span/src/analyze_source_file.rs
@@ -33,8 +33,8 @@ pub fn analyze_source_file(
     (lines, multi_byte_chars, non_narrow_chars)
 }
 
-cfg_if::cfg_if! {
-    if #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] {
+cfg_match! {
+    cfg(any(target_arch = "x86", target_arch = "x86_64")) => {
         fn analyze_source_file_dispatch(src: &str,
                                     lines: &mut Vec<RelativeBytePos>,
                                     multi_byte_chars: &mut Vec<MultiByteChar>,
@@ -172,8 +172,8 @@ cfg_if::cfg_if! {
                                         non_narrow_chars);
             }
         }
-    } else {
-
+    }
+    _ => {
         // The target (or compiler version) does not support SSE2 ...
         fn analyze_source_file_dispatch(src: &str,
                                     lines: &mut Vec<RelativeBytePos>,
diff --git a/compiler/rustc_span/src/fatal_error.rs b/compiler/rustc_span/src/fatal_error.rs
index fa84c486d..26c571109 100644
--- a/compiler/rustc_span/src/fatal_error.rs
+++ b/compiler/rustc_span/src/fatal_error.rs
@@ -1,13 +1,11 @@
-/// Used as a return value to signify a fatal error occurred. (It is also
-/// used as the argument to panic at the moment, but that will eventually
-/// not be true.)
+/// Used as a return value to signify a fatal error occurred.
 #[derive(Copy, Clone, Debug)]
 #[must_use]
 pub struct FatalError;
 
-pub struct FatalErrorMarker;
+pub use rustc_data_structures::FatalErrorMarker;
 
-// Don't implement Send on FatalError. This makes it impossible to panic!(FatalError).
+// Don't implement Send on FatalError. This makes it impossible to `panic_any!(FatalError)`.
 // We don't want to invoke the panic handler and print a backtrace for fatal errors.
 impl !Send for FatalError {}
 
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index 88081700c..36731d0fe 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -24,16 +24,13 @@
 // because getting it wrong can lead to nested `HygieneData::with` calls that
 // trigger runtime aborts. (Fortunately these are obvious and easy to fix.)
 
+use crate::def_id::{CrateNum, DefId, StableCrateId, CRATE_DEF_ID, LOCAL_CRATE};
 use crate::edition::Edition;
 use crate::symbol::{kw, sym, Symbol};
-use crate::with_session_globals;
-use crate::{HashStableContext, Span, DUMMY_SP};
-
-use crate::def_id::{CrateNum, DefId, StableCrateId, CRATE_DEF_ID, LOCAL_CRATE};
+use crate::{with_session_globals, HashStableContext, Span, DUMMY_SP};
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_data_structures::stable_hasher::HashingControls;
-use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher};
+use rustc_data_structures::stable_hasher::{Hash64, HashStable, HashingControls, StableHasher};
 use rustc_data_structures::sync::{Lock, Lrc, WorkerLocal};
 use rustc_data_structures::unhash::UnhashMap;
 use rustc_index::IndexVec;
@@ -130,7 +127,7 @@ impl ExpnHash {
 
     /// Returns the crate-local part of the [ExpnHash].
     ///
-    /// Used for tests.
+    /// Used for assertions.
     #[inline]
     pub fn local_hash(self) -> Hash64 {
         self.0.split().1
@@ -173,7 +170,7 @@ impl LocalExpnId {
     pub const ROOT: LocalExpnId = LocalExpnId::from_u32(0);
 
     #[inline]
-    pub fn from_raw(idx: ExpnIndex) -> LocalExpnId {
+    fn from_raw(idx: ExpnIndex) -> LocalExpnId {
         LocalExpnId::from_u32(idx.as_u32())
     }
 
@@ -205,11 +202,6 @@ impl LocalExpnId {
     }
 
     #[inline]
-    pub fn expn_hash(self) -> ExpnHash {
-        HygieneData::with(|data| data.local_expn_hash(self))
-    }
-
-    #[inline]
     pub fn expn_data(self) -> ExpnData {
         HygieneData::with(|data| data.local_expn_data(self).clone())
     }
@@ -239,13 +231,6 @@ impl LocalExpnId {
         self.to_expn_id().is_descendant_of(ancestor.to_expn_id())
     }
 
-    /// `expn_id.outer_expn_is_descendant_of(ctxt)` is equivalent to but faster than
-    /// `expn_id.is_descendant_of(ctxt.outer_expn())`.
-    #[inline]
-    pub fn outer_expn_is_descendant_of(self, ctxt: SyntaxContext) -> bool {
-        self.to_expn_id().outer_expn_is_descendant_of(ctxt)
-    }
-
     /// Returns span for the macro which originally caused this expansion to happen.
     ///
     /// Stops backtracing at include! boundary.
@@ -253,12 +238,6 @@ impl LocalExpnId {
     pub fn expansion_cause(self) -> Option<Span> {
         self.to_expn_id().expansion_cause()
     }
-
-    #[inline]
-    #[track_caller]
-    pub fn parent(self) -> LocalExpnId {
-        self.expn_data().parent.as_local().unwrap()
-    }
 }
 
 impl ExpnId {
@@ -333,7 +312,7 @@ impl ExpnId {
 }
 
 #[derive(Debug)]
-pub struct HygieneData {
+pub(crate) struct HygieneData {
     /// Each expansion should have an associated expansion data, but sometimes there's a delay
     /// between creation of an expansion ID and obtaining its data (e.g. macros are collected
     /// first and then resolved later), so we use an `Option` here.
@@ -384,16 +363,11 @@ impl HygieneData {
         }
     }
 
-    pub fn with<T, F: FnOnce(&mut HygieneData) -> T>(f: F) -> T {
+    fn with<T, F: FnOnce(&mut HygieneData) -> T>(f: F) -> T {
         with_session_globals(|session_globals| f(&mut session_globals.hygiene_data.borrow_mut()))
     }
 
     #[inline]
-    fn local_expn_hash(&self, expn_id: LocalExpnId) -> ExpnHash {
-        self.local_expn_hashes[expn_id]
-    }
-
-    #[inline]
     fn expn_hash(&self, expn_id: ExpnId) -> ExpnHash {
         match expn_id.as_local() {
             Some(expn_id) => self.local_expn_hashes[expn_id],
@@ -746,7 +720,7 @@ impl SyntaxContext {
     }
 
     /// Like `SyntaxContext::adjust`, but also normalizes `self` to macros 2.0.
-    pub fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
+    pub(crate) fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
         HygieneData::with(|data| {
             *self = data.normalize_to_macros_2_0(*self);
             data.adjust(self, expn_id)
@@ -779,7 +753,11 @@ impl SyntaxContext {
     /// ```
     /// This returns `None` if the context cannot be glob-adjusted.
     /// Otherwise, it returns the scope to use when privacy checking (see `adjust` for details).
-    pub fn glob_adjust(&mut self, expn_id: ExpnId, glob_span: Span) -> Option<Option<ExpnId>> {
+    pub(crate) fn glob_adjust(
+        &mut self,
+        expn_id: ExpnId,
+        glob_span: Span,
+    ) -> Option<Option<ExpnId>> {
         HygieneData::with(|data| {
             let mut scope = None;
             let mut glob_ctxt = data.normalize_to_macros_2_0(glob_span.ctxt());
@@ -803,7 +781,7 @@ impl SyntaxContext {
     ///     assert!(self.glob_adjust(expansion, glob_ctxt) == Some(privacy_checking_scope));
     /// }
     /// ```
-    pub fn reverse_glob_adjust(
+    pub(crate) fn reverse_glob_adjust(
         &mut self,
         expn_id: ExpnId,
         glob_span: Span,
@@ -858,11 +836,11 @@ impl SyntaxContext {
     }
 
     #[inline]
-    pub fn outer_mark(self) -> (ExpnId, Transparency) {
+    fn outer_mark(self) -> (ExpnId, Transparency) {
         HygieneData::with(|data| data.outer_mark(self))
     }
 
-    pub fn dollar_crate_name(self) -> Symbol {
+    pub(crate) fn dollar_crate_name(self) -> Symbol {
         HygieneData::with(|data| data.syntax_context_data[self.0 as usize].dollar_crate_name)
     }
 
@@ -961,12 +939,12 @@ pub struct ExpnData {
     /// The normal module (`mod`) in which the expanded macro was defined.
     pub parent_module: Option<DefId>,
     /// Suppresses the `unsafe_code` lint for code produced by this macro.
-    pub allow_internal_unsafe: bool,
+    pub(crate) allow_internal_unsafe: bool,
     /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
     pub local_inner_macros: bool,
     /// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
     /// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
-    pub collapse_debuginfo: bool,
+    pub(crate) collapse_debuginfo: bool,
 }
 
 impl !PartialEq for ExpnData {}
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 772e09291..489c8d189 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -4,28 +4,36 @@
 //!
 //! - the *span*, represented by [`SpanData`] and related types;
 //! - source code as represented by a [`SourceMap`]; and
-//! - interned strings, represented by [`Symbol`]s, with some common symbols available statically in the [`sym`] module.
+//! - interned strings, represented by [`Symbol`]s, with some common symbols available statically
+//!   in the [`sym`] module.
 //!
-//! Unlike most compilers, the span contains not only the position in the source code, but also various other metadata,
-//! such as the edition and macro hygiene. This metadata is stored in [`SyntaxContext`] and [`ExpnData`].
+//! Unlike most compilers, the span contains not only the position in the source code, but also
+//! various other metadata, such as the edition and macro hygiene. This metadata is stored in
+//! [`SyntaxContext`] and [`ExpnData`].
 //!
 //! ## Note
 //!
 //! This API is completely unstable and subject to change.
 
+// tidy-alphabetical-start
+#![allow(internal_features)]
+#![cfg_attr(not(bootstrap), doc(rust_logo))]
+#![cfg_attr(not(bootstrap), feature(rustdoc_internals))]
+#![deny(rustc::diagnostic_outside_of_impl)]
+#![deny(rustc::untranslatable_diagnostic)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(array_windows)]
+#![feature(cfg_match)]
+#![feature(core_io_borrowed_buf)]
 #![feature(if_let_guard)]
-#![feature(negative_impls)]
-#![feature(min_specialization)]
-#![feature(rustc_attrs)]
 #![feature(let_chains)]
-#![feature(round_char_boundary)]
-#![feature(read_buf)]
+#![feature(min_specialization)]
+#![feature(negative_impls)]
 #![feature(new_uninit)]
-#![deny(rustc::untranslatable_diagnostic)]
-#![deny(rustc::diagnostic_outside_of_impl)]
-#![allow(internal_features)]
+#![feature(read_buf)]
+#![feature(round_char_boundary)]
+#![feature(rustc_attrs)]
+// tidy-alphabetical-end
 
 #[macro_use]
 extern crate rustc_macros;
@@ -112,7 +120,6 @@ impl SessionGlobals {
     }
 }
 
-#[inline]
 pub fn create_session_globals_then<R>(edition: Edition, f: impl FnOnce() -> R) -> R {
     assert!(
         !SESSION_GLOBALS.is_set(),
@@ -123,7 +130,6 @@ pub fn create_session_globals_then<R>(edition: Edition, f: impl FnOnce() -> R) -
     SESSION_GLOBALS.set(&session_globals, f)
 }
 
-#[inline]
 pub fn set_session_globals_then<R>(session_globals: &SessionGlobals, f: impl FnOnce() -> R) -> R {
     assert!(
         !SESSION_GLOBALS.is_set(),
@@ -133,7 +139,6 @@ pub fn set_session_globals_then<R>(session_globals: &SessionGlobals, f: impl FnO
     SESSION_GLOBALS.set(session_globals, f)
 }
 
-#[inline]
 pub fn create_default_session_if_not_set_then<R, F>(f: F) -> R
 where
     F: FnOnce(&SessionGlobals) -> R,
@@ -141,7 +146,6 @@ where
     create_session_if_not_set_then(edition::DEFAULT_EDITION, f)
 }
 
-#[inline]
 pub fn create_session_if_not_set_then<R, F>(edition: Edition, f: F) -> R
 where
     F: FnOnce(&SessionGlobals) -> R,
@@ -154,7 +158,6 @@ where
     }
 }
 
-#[inline]
 pub fn with_session_globals<R, F>(f: F) -> R
 where
     F: FnOnce(&SessionGlobals) -> R,
@@ -162,7 +165,6 @@ where
     SESSION_GLOBALS.with(f)
 }
 
-#[inline]
 pub fn create_default_session_globals_then<R>(f: impl FnOnce() -> R) -> R {
     create_session_globals_then(edition::DEFAULT_EDITION, f)
 }
@@ -174,8 +176,7 @@ scoped_tls::scoped_thread_local!(static SESSION_GLOBALS: SessionGlobals);
 
 // FIXME: We should use this enum or something like it to get rid of the
 // use of magic `/rust/1.x/...` paths across the board.
-#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd)]
-#[derive(Decodable)]
+#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Decodable)]
 pub enum RealFileName {
     LocalPath(PathBuf),
     /// For remapped paths (namely paths into libstd that have been mapped
@@ -212,8 +213,8 @@ impl<S: Encoder> Encodable<S> for RealFileName {
 
             RealFileName::Remapped { ref local_path, ref virtual_name } => encoder
                 .emit_enum_variant(1, |encoder| {
-                    // For privacy and build reproducibility, we must not embed host-dependant path in artifacts
-                    // if they have been remapped by --remap-path-prefix
+                    // For privacy and build reproducibility, we must not embed host-dependant path
+                    // in artifacts if they have been remapped by --remap-path-prefix
                     assert!(local_path.is_none());
                     local_path.encode(encoder);
                     virtual_name.encode(encoder);
@@ -280,8 +281,7 @@ impl RealFileName {
 }
 
 /// Differentiates between real files and common virtual files.
-#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash)]
-#[derive(Decodable, Encodable)]
+#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash, Decodable, Encodable)]
 pub enum FileName {
     Real(RealFileName),
     /// Call to `quote!`.
@@ -292,8 +292,6 @@ pub enum FileName {
     // FIXME(jseyfried)
     MacroExpansion(Hash64),
     ProcMacroSourceCode(Hash64),
-    /// Strings provided as `--cfg [cfgspec]` stored in a `crate_cfg`.
-    CfgSpec(Hash64),
     /// Strings provided as crate attributes in the CLI.
     CliCrateAttr(Hash64),
     /// Custom sources for explicit parser calls from plugins and drivers.
@@ -305,7 +303,6 @@ pub enum FileName {
 
 impl From<PathBuf> for FileName {
     fn from(p: PathBuf) -> Self {
-        assert!(!p.to_string_lossy().ends_with('>'));
         FileName::Real(RealFileName::LocalPath(p))
     }
 }
@@ -339,7 +336,6 @@ impl fmt::Display for FileNameDisplay<'_> {
             MacroExpansion(_) => write!(fmt, "<macro expansion>"),
             Anon(_) => write!(fmt, "<anon>"),
             ProcMacroSourceCode(_) => write!(fmt, "<proc-macro source code>"),
-            CfgSpec(_) => write!(fmt, "<cfgspec>"),
             CliCrateAttr(_) => write!(fmt, "<crate attribute>"),
             Custom(ref s) => write!(fmt, "<{s}>"),
             DocTest(ref path, _) => write!(fmt, "{}", path.display()),
@@ -365,7 +361,6 @@ impl FileName {
             Anon(_)
             | MacroExpansion(_)
             | ProcMacroSourceCode(_)
-            | CfgSpec(_)
             | CliCrateAttr(_)
             | Custom(_)
             | QuoteExpansion(_)
@@ -374,7 +369,7 @@ impl FileName {
         }
     }
 
-    pub fn prefer_remapped(&self) -> FileNameDisplay<'_> {
+    pub fn prefer_remapped_unconditionaly(&self) -> FileNameDisplay<'_> {
         FileNameDisplay { inner: self, display_pref: FileNameDisplayPreference::Remapped }
     }
 
@@ -955,7 +950,7 @@ impl Span {
     /// Produces a span with the same location as `self` and context produced by a macro with the
     /// given ID and transparency, assuming that macro was defined directly and not produced by
     /// some other macro (which is the case for built-in and procedural macros).
-    pub fn with_ctxt_from_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span {
+    fn with_ctxt_from_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span {
         self.with_ctxt(SyntaxContext::root().apply_mark(expn_id, transparency))
     }
 
@@ -1530,7 +1525,8 @@ impl SourceFile {
         })
     }
 
-    /// This converts the `lines` field to contain `SourceFileLines::Lines` if needed and freezes it.
+    /// This converts the `lines` field to contain `SourceFileLines::Lines` if needed and freezes
+    /// it.
     fn convert_diffs_to_lines_frozen(&self) {
         let mut guard = if let Some(guard) = self.lines.try_write() { guard } else { return };
 
@@ -2248,7 +2244,10 @@ where
 
 /// Useful type to use with `Result<>` indicate that an error has already
 /// been reported to the user, so no need to continue checking.
-#[derive(Clone, Copy, Debug, Encodable, Decodable, Hash, PartialEq, Eq, PartialOrd, Ord)]
+///
+/// The `()` field is necessary: it is non-`pub`, which means values of this
+/// type cannot be constructed outside of this crate.
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
 #[derive(HashStable_Generic)]
 pub struct ErrorGuaranteed(());
 
@@ -2260,3 +2259,21 @@ impl ErrorGuaranteed {
         ErrorGuaranteed(())
     }
 }
+
+impl<E: rustc_serialize::Encoder> Encodable<E> for ErrorGuaranteed {
+    #[inline]
+    fn encode(&self, _e: &mut E) {
+        panic!(
+            "should never serialize an `ErrorGuaranteed`, as we do not write metadata or \
+            incremental caches in case errors occurred"
+        )
+    }
+}
+impl<D: rustc_serialize::Decoder> Decodable<D> for ErrorGuaranteed {
+    #[inline]
+    fn decode(_d: &mut D) -> ErrorGuaranteed {
+        panic!(
+            "`ErrorGuaranteed` should never have been serialized to metadata or incremental caches"
+        )
+    }
+}
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index 0b575c13a..dcf346acb 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -9,21 +9,16 @@
 //! within the `SourceMap`, which upon request can be converted to line and column
 //! information, source code snippets, etc.
 
-pub use crate::hygiene::{ExpnData, ExpnKind};
-pub use crate::*;
-
+use crate::*;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{Hash128, Hash64, StableHasher};
 use rustc_data_structures::sync::{IntoDynSyncSend, Lrc, MappedReadGuard, ReadGuard, RwLock};
 use std::cmp;
+use std::fs;
 use std::hash::Hash;
+use std::io::{self, BorrowedBuf, Read};
 use std::path::{self, Path, PathBuf};
 
-use std::fs;
-use std::io;
-use std::io::BorrowedBuf;
-use std::io::Read;
-
 #[cfg(test)]
 mod tests;
 
@@ -41,7 +36,7 @@ pub fn original_sp(sp: Span, enclosing_sp: Span) -> Span {
     }
 }
 
-pub mod monotonic {
+mod monotonic {
     use std::ops::{Deref, DerefMut};
 
     /// A `MonotonicVec` is a `Vec` which can only be grown.
@@ -51,18 +46,14 @@ pub mod monotonic {
     // field is inaccessible
     pub struct MonotonicVec<T>(Vec<T>);
     impl<T> MonotonicVec<T> {
-        pub fn new(val: Vec<T>) -> MonotonicVec<T> {
-            MonotonicVec(val)
-        }
-
-        pub fn push(&mut self, val: T) {
+        pub(super) fn push(&mut self, val: T) {
             self.0.push(val);
         }
     }
 
     impl<T> Default for MonotonicVec<T> {
         fn default() -> Self {
-            MonotonicVec::new(vec![])
+            MonotonicVec(vec![])
         }
     }
 
@@ -207,7 +198,7 @@ impl StableSourceFileId {
 //
 
 #[derive(Default)]
-pub(super) struct SourceMapFiles {
+struct SourceMapFiles {
     source_files: monotonic::MonotonicVec<Lrc<SourceFile>>,
     stable_id_to_source_file: FxHashMap<StableSourceFileId, Lrc<SourceFile>>,
 }
@@ -466,33 +457,6 @@ impl SourceMap {
         self.span_to_string(sp, FileNameDisplayPreference::Remapped)
     }
 
-    /// Format the span location suitable for pretty printing annotations with relative line numbers
-    pub fn span_to_relative_line_string(&self, sp: Span, relative_to: Span) -> String {
-        if self.files.borrow().source_files.is_empty() || sp.is_dummy() || relative_to.is_dummy() {
-            return "no-location".to_string();
-        }
-
-        let lo = self.lookup_char_pos(sp.lo());
-        let hi = self.lookup_char_pos(sp.hi());
-        let offset = self.lookup_char_pos(relative_to.lo());
-
-        if lo.file.name != offset.file.name || !relative_to.contains(sp) {
-            return self.span_to_embeddable_string(sp);
-        }
-
-        let lo_line = lo.line.saturating_sub(offset.line);
-        let hi_line = hi.line.saturating_sub(offset.line);
-
-        format!(
-            "{}:+{}:{}: +{}:{}",
-            lo.file.name.display(FileNameDisplayPreference::Remapped),
-            lo_line,
-            lo.col.to_usize() + 1,
-            hi_line,
-            hi.col.to_usize() + 1,
-        )
-    }
-
     /// Format the span location to be printed in diagnostics. Must not be emitted
     /// to build artifacts as this may leak local file paths. Use span_to_embeddable_string
     /// for string suitable for embedding.
@@ -1124,16 +1088,13 @@ pub struct FilePathMapping {
 
 impl FilePathMapping {
     pub fn empty() -> FilePathMapping {
-        FilePathMapping::new(Vec::new())
+        FilePathMapping::new(Vec::new(), FileNameDisplayPreference::Local)
     }
 
-    pub fn new(mapping: Vec<(PathBuf, PathBuf)>) -> FilePathMapping {
-        let filename_display_for_diagnostics = if mapping.is_empty() {
-            FileNameDisplayPreference::Local
-        } else {
-            FileNameDisplayPreference::Remapped
-        };
-
+    pub fn new(
+        mapping: Vec<(PathBuf, PathBuf)>,
+        filename_display_for_diagnostics: FileNameDisplayPreference,
+    ) -> FilePathMapping {
         FilePathMapping { mapping, filename_display_for_diagnostics }
     }
 
@@ -1287,6 +1248,27 @@ impl FilePathMapping {
         }
     }
 
+    /// Expand a relative path to an absolute path **without** remapping taken into account.
+    ///
+    /// The resulting `RealFileName` will have its `virtual_path` portion erased if
+    /// possible (i.e. if there's also a remapped path).
+    pub fn to_local_embeddable_absolute_path(
+        &self,
+        file_path: RealFileName,
+        working_directory: &RealFileName,
+    ) -> RealFileName {
+        let file_path = file_path.local_path_if_available();
+        if file_path.is_absolute() {
+            // No remapping has applied to this path and it is absolute,
+            // so the working directory cannot influence it either, so
+            // we are done.
+            return RealFileName::LocalPath(file_path.to_path_buf());
+        }
+        debug_assert!(file_path.is_relative());
+        let working_directory = working_directory.local_path_if_available();
+        RealFileName::LocalPath(Path::new(working_directory).join(file_path))
+    }
+
     /// Attempts to (heuristically) reverse a prefix mapping.
     ///
     /// Returns [`Some`] if there is exactly one mapping where the "to" part is
diff --git a/compiler/rustc_span/src/source_map/tests.rs b/compiler/rustc_span/src/source_map/tests.rs
index a12f50c87..5697969dd 100644
--- a/compiler/rustc_span/src/source_map/tests.rs
+++ b/compiler/rustc_span/src/source_map/tests.rs
@@ -351,7 +351,10 @@ fn reverse_map_prefix(mapping: &FilePathMapping, p: &str) -> Option<String> {
 fn path_prefix_remapping() {
     // Relative to relative
     {
-        let mapping = &FilePathMapping::new(vec![(path("abc/def"), path("foo"))]);
+        let mapping = &FilePathMapping::new(
+            vec![(path("abc/def"), path("foo"))],
+            FileNameDisplayPreference::Remapped,
+        );
 
         assert_eq!(map_path_prefix(mapping, "abc/def/src/main.rs"), path_str("foo/src/main.rs"));
         assert_eq!(map_path_prefix(mapping, "abc/def"), path_str("foo"));
@@ -359,7 +362,10 @@ fn path_prefix_remapping() {
 
     // Relative to absolute
     {
-        let mapping = &FilePathMapping::new(vec![(path("abc/def"), path("/foo"))]);
+        let mapping = &FilePathMapping::new(
+            vec![(path("abc/def"), path("/foo"))],
+            FileNameDisplayPreference::Remapped,
+        );
 
         assert_eq!(map_path_prefix(mapping, "abc/def/src/main.rs"), path_str("/foo/src/main.rs"));
         assert_eq!(map_path_prefix(mapping, "abc/def"), path_str("/foo"));
@@ -367,7 +373,10 @@ fn path_prefix_remapping() {
 
     // Absolute to relative
     {
-        let mapping = &FilePathMapping::new(vec![(path("/abc/def"), path("foo"))]);
+        let mapping = &FilePathMapping::new(
+            vec![(path("/abc/def"), path("foo"))],
+            FileNameDisplayPreference::Remapped,
+        );
 
         assert_eq!(map_path_prefix(mapping, "/abc/def/src/main.rs"), path_str("foo/src/main.rs"));
         assert_eq!(map_path_prefix(mapping, "/abc/def"), path_str("foo"));
@@ -375,7 +384,10 @@ fn path_prefix_remapping() {
 
     // Absolute to absolute
     {
-        let mapping = &FilePathMapping::new(vec![(path("/abc/def"), path("/foo"))]);
+        let mapping = &FilePathMapping::new(
+            vec![(path("/abc/def"), path("/foo"))],
+            FileNameDisplayPreference::Remapped,
+        );
 
         assert_eq!(map_path_prefix(mapping, "/abc/def/src/main.rs"), path_str("/foo/src/main.rs"));
         assert_eq!(map_path_prefix(mapping, "/abc/def"), path_str("/foo"));
@@ -385,8 +397,10 @@ fn path_prefix_remapping() {
 #[test]
 fn path_prefix_remapping_expand_to_absolute() {
     // "virtual" working directory is relative path
-    let mapping =
-        &FilePathMapping::new(vec![(path("/foo"), path("FOO")), (path("/bar"), path("BAR"))]);
+    let mapping = &FilePathMapping::new(
+        vec![(path("/foo"), path("FOO")), (path("/bar"), path("BAR"))],
+        FileNameDisplayPreference::Remapped,
+    );
     let working_directory = path("/foo");
     let working_directory = RealFileName::Remapped {
         local_path: Some(working_directory.clone()),
@@ -487,8 +501,10 @@ fn path_prefix_remapping_expand_to_absolute() {
 fn path_prefix_remapping_reverse() {
     // Ignores options without alphanumeric chars.
     {
-        let mapping =
-            &FilePathMapping::new(vec![(path("abc"), path("/")), (path("def"), path("."))]);
+        let mapping = &FilePathMapping::new(
+            vec![(path("abc"), path("/")), (path("def"), path("."))],
+            FileNameDisplayPreference::Remapped,
+        );
 
         assert_eq!(reverse_map_prefix(mapping, "/hello.rs"), None);
         assert_eq!(reverse_map_prefix(mapping, "./hello.rs"), None);
@@ -496,20 +512,20 @@ fn path_prefix_remapping_reverse() {
 
     // Returns `None` if multiple options match.
     {
-        let mapping = &FilePathMapping::new(vec![
-            (path("abc"), path("/redacted")),
-            (path("def"), path("/redacted")),
-        ]);
+        let mapping = &FilePathMapping::new(
+            vec![(path("abc"), path("/redacted")), (path("def"), path("/redacted"))],
+            FileNameDisplayPreference::Remapped,
+        );
 
         assert_eq!(reverse_map_prefix(mapping, "/redacted/hello.rs"), None);
     }
 
     // Distinct reverse mappings.
     {
-        let mapping = &FilePathMapping::new(vec![
-            (path("abc"), path("/redacted")),
-            (path("def/ghi"), path("/fake/dir")),
-        ]);
+        let mapping = &FilePathMapping::new(
+            vec![(path("abc"), path("/redacted")), (path("def/ghi"), path("/fake/dir"))],
+            FileNameDisplayPreference::Remapped,
+        );
 
         assert_eq!(
             reverse_map_prefix(mapping, "/redacted/path/hello.rs"),
diff --git a/compiler/rustc_span/src/span_encoding.rs b/compiler/rustc_span/src/span_encoding.rs
index 93ab15460..f7d17a267 100644
--- a/compiler/rustc_span/src/span_encoding.rs
+++ b/compiler/rustc_span/src/span_encoding.rs
@@ -126,7 +126,7 @@ impl Span {
                 return Span {
                     lo_or_index: lo2,
                     len_with_tag_or_marker: PARENT_TAG | len as u16,
-                    ctxt_or_parent_or_marker: parent2 as u16
+                    ctxt_or_parent_or_marker: parent2 as u16,
                 };
             }
         }
@@ -212,6 +212,7 @@ impl Span {
 
     /// This function is used as a fast path when decoding the full `SpanData` is not necessary.
     /// It's a cut-down version of `data_untracked`.
+    #[cfg_attr(not(test), rustc_diagnostic_item = "SpanCtxt")]
     #[inline]
     pub fn ctxt(self) -> SyntaxContext {
         if self.len_with_tag_or_marker != BASE_LEN_INTERNED_MARKER {
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 4f4625662..f287862cc 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -3,7 +3,7 @@
 //! type, and vice versa.
 
 use rustc_arena::DroplessArena;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
 use rustc_data_structures::sync::Lock;
 use rustc_macros::HashStable_Generic;
@@ -20,8 +20,8 @@ mod tests;
 
 // The proc macro code for this is in `compiler/rustc_macros/src/symbols.rs`.
 symbols! {
-    // After modifying this list adjust `is_special`, `is_used_keyword`/`is_unused_keyword`,
-    // this should be rarely necessary though if the keywords are kept in alphabetic order.
+    // If you modify this list, adjust `is_special` and `is_used_keyword`/`is_unused_keyword`.
+    // But this should rarely be necessary if the keywords are kept in alphabetic order.
     Keywords {
         // Special reserved identifiers used internally for elided lifetimes,
         // unnamed method parameters, crate root module, error recovery etc.
@@ -98,6 +98,7 @@ symbols! {
         Builtin:            "builtin",
         Catch:              "catch",
         Default:            "default",
+        Gen:                "gen",
         MacroRules:         "macro_rules",
         Raw:                "raw",
         Union:              "union",
@@ -129,9 +130,11 @@ symbols! {
         Alignment,
         Any,
         Arc,
+        ArcWeak,
         Argument,
         ArgumentMethods,
         Arguments,
+        ArrayIntoIter,
         AsMut,
         AsRef,
         AssertParamIsClone,
@@ -164,6 +167,7 @@ symbols! {
         Capture,
         Center,
         Clone,
+        Command,
         ConstParamTy,
         Context,
         Continue,
@@ -171,6 +175,7 @@ symbols! {
         Count,
         Cow,
         Debug,
+        DebugStruct,
         Decodable,
         Decoder,
         DecorateLint,
@@ -189,11 +194,16 @@ symbols! {
         Error,
         File,
         FileType,
+        Fn,
+        FnMut,
+        FnOnce,
         FormatSpec,
         Formatter,
         From,
         FromIterator,
         FromResidual,
+        FsOpenOptions,
+        FsPermissions,
         Future,
         FutureOutput,
         FxHashMap,
@@ -207,16 +217,23 @@ symbols! {
         Implied,
         IndexOutput,
         Input,
+        Instant,
         Into,
         IntoDiagnostic,
         IntoFuture,
         IntoIterator,
+        IoLines,
         IoRead,
+        IoSeek,
         IoWrite,
         IpAddr,
         IrTyKind,
         Is,
+        Item,
         ItemContext,
+        IterEmpty,
+        IterOnce,
+        IterPeekable,
         Iterator,
         IteratorItem,
         Layout,
@@ -227,6 +244,7 @@ symbols! {
         Mutex,
         MutexGuard,
         N,
+        NonNull,
         NonZeroI128,
         NonZeroI16,
         NonZeroI32,
@@ -259,15 +277,19 @@ symbols! {
         ProcMacro,
         ProceduralMasqueradeDummyType,
         Range,
+        RangeBounds,
         RangeFrom,
         RangeFull,
         RangeInclusive,
         RangeTo,
         RangeToInclusive,
         Rc,
+        RcWeak,
         Ready,
         Receiver,
         RefCell,
+        RefCellRef,
+        RefCellRefMut,
         Relaxed,
         Release,
         Result,
@@ -284,7 +306,9 @@ symbols! {
         Send,
         SeqCst,
         SliceIndex,
+        SliceIter,
         Some,
+        SpanCtxt,
         String,
         StructuralEq,
         StructuralPartialEq,
@@ -295,6 +319,7 @@ symbols! {
         ToOwned,
         ToString,
         TokenStream,
+        Trait,
         Try,
         TryCaptureGeneric,
         TryCapturePrintable,
@@ -561,6 +586,7 @@ symbols! {
         constant,
         constructor,
         context,
+        convert_identity,
         copy,
         copy_closures,
         copy_nonoverlapping,
@@ -571,6 +597,10 @@ symbols! {
         core_panic_2015_macro,
         core_panic_2021_macro,
         core_panic_macro,
+        coroutine,
+        coroutine_clone,
+        coroutine_state,
+        coroutines,
         cosf32,
         cosf64,
         count,
@@ -616,6 +646,7 @@ symbols! {
         declare_lint_pass,
         decode,
         default_alloc_error_handler,
+        default_fn,
         default_lib_allocator,
         default_method_body_is_const,
         default_type_parameter_fallback,
@@ -628,6 +659,7 @@ symbols! {
         deref,
         deref_method,
         deref_mut,
+        deref_mut_method,
         deref_target,
         derive,
         derive_const,
@@ -687,6 +719,7 @@ symbols! {
         encode,
         end,
         env,
+        env_CFG_RELEASE: env!("CFG_RELEASE"),
         eprint_macro,
         eprintln_macro,
         eq,
@@ -777,22 +810,24 @@ symbols! {
         from_desugaring,
         from_fn,
         from_iter,
+        from_iter_fn,
         from_output,
         from_residual,
         from_size_align_unchecked,
+        from_str_method,
         from_usize,
         from_yeet,
+        fs_create_dir,
         fsub_fast,
         fundamental,
         future,
         future_trait,
         gdb_script_file,
         ge,
+        gen_blocks,
         gen_future,
         gen_kill,
-        generator,
         generator_clone,
-        generator_state,
         generators,
         generic_arg_infer,
         generic_assert,
@@ -862,12 +897,16 @@ symbols! {
         inline_const_pat,
         inout,
         instruction_set,
-        integer_: "integer",
+        integer_: "integer", // underscore to avoid clashing with the function `sym::integer` below
         integral,
         into_future,
         into_iter,
         intra_doc_pointers,
         intrinsics,
+        intrinsics_unaligned_volatile_load,
+        intrinsics_unaligned_volatile_store,
+        io_stderr,
+        io_stdout,
         irrefutable_let_patterns,
         isa_attribute,
         isize,
@@ -879,6 +918,7 @@ symbols! {
         iter,
         iter_mut,
         iter_repeat,
+        iterator,
         iterator_collect_fn,
         kcfi,
         keyword,
@@ -926,6 +966,7 @@ symbols! {
         log_syntax,
         logf32,
         logf64,
+        loongarch_target_feature,
         loop_break_value,
         lt,
         macro_at_most_once_rep,
@@ -962,6 +1003,7 @@ symbols! {
         mem_replace,
         mem_size_of,
         mem_size_of_val,
+        mem_swap,
         mem_uninitialized,
         mem_variant_count,
         mem_zeroed,
@@ -1075,6 +1117,7 @@ symbols! {
         off,
         offset,
         offset_of,
+        offset_of_enum,
         omit_gdb_pretty_printer_section,
         on,
         on_unimplemented,
@@ -1091,6 +1134,7 @@ symbols! {
         options,
         or,
         or_patterns,
+        ord_cmp_method,
         other,
         out,
         overflow_checks,
@@ -1104,7 +1148,6 @@ symbols! {
         panic_abort,
         panic_bounds_check,
         panic_cannot_unwind,
-        panic_display,
         panic_fmt,
         panic_handler,
         panic_impl,
@@ -1172,6 +1215,7 @@ symbols! {
         proc_macro_mod,
         proc_macro_non_items,
         proc_macro_path_invoc,
+        process_exit,
         profiler_builtins,
         profiler_runtime,
         ptr,
@@ -1179,6 +1223,10 @@ symbols! {
         ptr_cast_const,
         ptr_cast_mut,
         ptr_const_is_null,
+        ptr_copy,
+        ptr_copy_nonoverlapping,
+        ptr_drop_in_place,
+        ptr_eq,
         ptr_from_ref,
         ptr_guaranteed_cmp,
         ptr_is_null,
@@ -1187,8 +1235,17 @@ symbols! {
         ptr_null_mut,
         ptr_offset_from,
         ptr_offset_from_unsigned,
+        ptr_read,
+        ptr_read_unaligned,
+        ptr_read_volatile,
+        ptr_replace,
+        ptr_slice_from_raw_parts,
+        ptr_slice_from_raw_parts_mut,
+        ptr_swap,
+        ptr_swap_nonoverlapping,
         ptr_unique,
         ptr_write,
+        ptr_write_bytes,
         ptr_write_unaligned,
         ptr_write_volatile,
         pub_macro_rules,
@@ -1284,6 +1341,7 @@ symbols! {
         rust_cold_cc,
         rust_eh_catch_typeinfo,
         rust_eh_personality,
+        rust_logo,
         rustc,
         rustc_abi,
         rustc_allocator,
@@ -1299,6 +1357,7 @@ symbols! {
         rustc_coherence_is_core,
         rustc_coinductive,
         rustc_confusables,
+        rustc_const_panic_str,
         rustc_const_stable,
         rustc_const_unstable,
         rustc_conversion_suggestion,
@@ -1321,6 +1380,7 @@ symbols! {
         rustc_evaluate_where_clauses,
         rustc_expected_cgu_reuse,
         rustc_has_incoherent_inherent_impls,
+        rustc_hidden_type_of_opaques,
         rustc_host,
         rustc_if_this_changed,
         rustc_inherit_overflow_checks,
@@ -1478,6 +1538,8 @@ symbols! {
         sized,
         skip,
         slice,
+        slice_from_raw_parts,
+        slice_from_raw_parts_mut,
         slice_len_fn,
         slice_patterns,
         slicing_syntax,
@@ -1565,7 +1627,9 @@ symbols! {
         thumb2,
         thumb_mode: "thumb-mode",
         tmm_reg,
+        to_owned_method,
         to_string,
+        to_string_method,
         to_vec,
         todo_macro,
         tool_attributes,
@@ -1588,6 +1652,7 @@ symbols! {
         try_blocks,
         try_capture,
         try_from,
+        try_from_fn,
         try_into,
         try_trait_v2,
         tt,
@@ -1722,6 +1787,7 @@ symbols! {
         xmm_reg,
         yeet_desugar_details,
         yeet_expr,
+        yield_expr,
         ymm_reg,
         zmm_reg,
     }
@@ -2015,43 +2081,33 @@ impl<CTX> ToStableHashKey<CTX> for Symbol {
     }
 }
 
-#[derive(Default)]
 pub(crate) struct Interner(Lock<InternerInner>);
 
 // The `&'static str`s in this type actually point into the arena.
 //
-// The `FxHashMap`+`Vec` pair could be replaced by `FxIndexSet`, but #75278
-// found that to regress performance up to 2% in some cases. This might be
-// revisited after further improvements to `indexmap`.
-//
 // This type is private to prevent accidentally constructing more than one
 // `Interner` on the same thread, which makes it easy to mix up `Symbol`s
 // between `Interner`s.
-#[derive(Default)]
 struct InternerInner {
     arena: DroplessArena,
-    names: FxHashMap<&'static str, Symbol>,
-    strings: Vec<&'static str>,
+    strings: FxIndexSet<&'static str>,
 }
 
 impl Interner {
     fn prefill(init: &[&'static str]) -> Self {
         Interner(Lock::new(InternerInner {
-            strings: init.into(),
-            names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
-            ..Default::default()
+            arena: Default::default(),
+            strings: init.iter().copied().collect(),
         }))
     }
 
     #[inline]
     fn intern(&self, string: &str) -> Symbol {
         let mut inner = self.0.lock();
-        if let Some(&name) = inner.names.get(string) {
-            return name;
+        if let Some(idx) = inner.strings.get_index_of(string) {
+            return Symbol::new(idx as u32);
         }
 
-        let name = Symbol::new(inner.strings.len() as u32);
-
         // SAFETY: we convert from `&str` to `&[u8]`, clone it into the arena,
         // and immediately convert the clone back to `&[u8]`, all because there
         // is no `inner.arena.alloc_str()` method. This is clearly safe.
@@ -2061,20 +2117,21 @@ impl Interner {
         // SAFETY: we can extend the arena allocation to `'static` because we
         // only access these while the arena is still alive.
         let string: &'static str = unsafe { &*(string as *const str) };
-        inner.strings.push(string);
 
         // This second hash table lookup can be avoided by using `RawEntryMut`,
         // but this code path isn't hot enough for it to be worth it. See
         // #91445 for details.
-        inner.names.insert(string, name);
-        name
+        let (idx, is_new) = inner.strings.insert_full(string);
+        debug_assert!(is_new); // due to the get_index_of check above
+
+        Symbol::new(idx as u32)
     }
 
     /// Get the symbol as a string.
     ///
     /// [`Symbol::as_str()`] should be used in preference to this function.
     fn get(&self, symbol: Symbol) -> &str {
-        self.0.lock().strings[symbol.0.as_usize()]
+        self.0.lock().strings.get_index(symbol.0.as_usize()).unwrap()
     }
 }
 
@@ -2132,8 +2189,9 @@ impl Symbol {
         self >= kw::Abstract && self <= kw::Yield
     }
 
-    fn is_unused_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
-        self == kw::Try && edition() >= Edition::Edition2018
+    fn is_unused_keyword_conditional(self, edition: impl Copy + FnOnce() -> Edition) -> bool {
+        self == kw::Try && edition().at_least_rust_2018()
+            || self == kw::Gen && edition().at_least_rust_2024()
     }
 
     pub fn is_reserved(self, edition: impl Copy + FnOnce() -> Edition) -> bool {
diff --git a/compiler/rustc_span/src/symbol/tests.rs b/compiler/rustc_span/src/symbol/tests.rs
index 0958fce5f..4366c5a2c 100644
--- a/compiler/rustc_span/src/symbol/tests.rs
+++ b/compiler/rustc_span/src/symbol/tests.rs
@@ -4,7 +4,7 @@ use crate::create_default_session_globals_then;
 
 #[test]
 fn interner_tests() {
-    let i = Interner::default();
+    let i = Interner::prefill(&[]);
     // first one is zero:
     assert_eq!(i.intern("dog"), Symbol::new(0));
     // re-use gets the same entry: