Rollup of 17 pull requests

.github/ISSUE_TEMPLATE/library_tracking_issue.md

@@ -2,7 +2,7 @@
 name: Library Tracking Issue
 about: A tracking issue for an unstable library feature.
 title: Tracking Issue for XXX
-labels: C-tracking-issue T-libs
+labels: C-tracking-issue, T-libs
 ---
 <!--
 Thank you for creating a tracking issue!

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -257,7 +257,10 @@ pub struct Substructure<'a> {
     pub type_ident: Ident,
     /// ident of the method
     pub method_ident: Ident,
-    /// dereferenced access to any `Self_` or `Ptr(Self_, _)` arguments
+    /// dereferenced access to any [`Self_`] or [`Ptr(Self_, _)][ptr]` arguments
+    ///
+    /// [`Self_`]: ty::Ty::Self_
+    /// [ptr]: ty::Ty::Ptr
     pub self_args: &'a [P<Expr>],
     /// verbatim access to any other arguments
     pub nonself_args: &'a [P<Expr>],

compiler/rustc_interface/src/interface.rs

@@ -25,8 +25,9 @@ use std::sync::{Arc, Mutex};
 pub type Result<T> = result::Result<T, ErrorReported>;
 
 /// Represents a compiler session.
+///
 /// Can be used to run `rustc_interface` queries.
-/// Created by passing `Config` to `run_compiler`.
+/// Created by passing [`Config`] to [`run_compiler`].
 pub struct Compiler {
     pub(crate) sess: Lrc<Session>,
     codegen_backend: Lrc<Box<dyn CodegenBackend>>,

compiler/rustc_interface/src/passes.rs

@@ -95,7 +95,7 @@ declare_box_region_type!(
 /// harness if one is to be provided, injection of a dependency on the
 /// standard library and prelude, and name resolution.
 ///
-/// Returns `None` if we're aborting after handling -W help.
+/// Returns [`None`] if we're aborting after handling -W help.
 pub fn configure_and_expand(
     sess: Lrc<Session>,
     lint_store: Lrc<LintStore>,

compiler/rustc_interface/src/queries.rs

@@ -23,7 +23,11 @@ use std::cell::{Ref, RefCell, RefMut};
 use std::rc::Rc;
 
 /// Represent the result of a query.
-/// This result can be stolen with the `take` method and generated with the `compute` method.
+///
+/// This result can be stolen with the [`take`] method and generated with the [`compute`] method.
+///
+/// [`take`]: Self::take
+/// [`compute`]: Self::compute
 pub struct Query<T> {
     result: RefCell<Option<Result<T>>>,
 }

compiler/rustc_middle/src/lib.rs

@@ -8,7 +8,7 @@
 //! - **MIR.** The "mid-level (M) intermediate representation (IR)" is
 //!   defined in the `mir` module. This module contains only the
 //!   *definition* of the MIR; the passes that transform and operate
-//!   on MIR are found in `librustc_mir` crate.
+//!   on MIR are found in `rustc_mir` crate.
 //! - **Types.** The internal representation of types used in rustc is
 //!   defined in the `ty` module. This includes the **type context**
 //!   (or `tcx`), which is the central context during most of

compiler/rustc_middle/src/lint.rs

@@ -22,8 +22,8 @@ pub enum LintSource {
     Node(Symbol, Span, Option<Symbol> /* RFC 2383 reason */),
 
     /// Lint level was set by a command-line flag.
-    /// The provided `Level` is the level specified on the command line -
-    /// the actual level may be lower due to `--cap-lints`
+    /// The provided `Level` is the level specified on the command line.
+    /// (The actual level may be lower due to `--cap-lints`.)
     CommandLine(Symbol, Level),
 }
 

compiler/rustc_middle/src/middle/privacy.rs

@@ -8,7 +8,9 @@ use rustc_macros::HashStable;
 use std::fmt;
 use std::hash::Hash;
 
-// Accessibility levels, sorted in ascending order
+/// Represents the levels of accessibility an item can have.
+///
+/// The variants are sorted in ascending order of accessibility.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, HashStable)]
 pub enum AccessLevel {
     /// Superset of `AccessLevel::Reachable` used to mark impl Trait items.
@@ -18,13 +20,13 @@ pub enum AccessLevel {
     /// public, then type `T` is reachable. Its values can be obtained by other crates
     /// even if the type itself is not nameable.
     Reachable,
-    /// Public items + items accessible to other crates with help of `pub use` re-exports
+    /// Public items + items accessible to other crates with the help of `pub use` re-exports.
     Exported,
-    /// Items accessible to other crates directly, without help of re-exports
+    /// Items accessible to other crates directly, without the help of re-exports.
     Public,
 }
 
-// Accessibility levels for reachable HIR nodes
+/// Holds a map of accessibility levels for reachable HIR nodes.
 #[derive(Clone)]
 pub struct AccessLevels<Id = HirId> {
     pub map: FxHashMap<Id, AccessLevel>,

compiler/rustc_middle/src/middle/region.rs

@@ -332,7 +332,7 @@ pub struct ScopeTree {
 pub struct YieldData {
     /// The `Span` of the yield.
     pub span: Span,
-    /// The number of expressions and patterns appearing before the `yield` in the body plus one.
+    /// The number of expressions and patterns appearing before the `yield` in the body, plus one.
     pub expr_and_pat_count: usize,
     pub source: hir::YieldSource,
 }
@@ -449,9 +449,7 @@ impl ScopeTree {
     }
 
     /// Checks whether the given scope contains a `yield`. If so,
-    /// returns `Some((span, expr_count))` with the span of a yield we found and
-    /// the number of expressions and patterns appearing before the `yield` in the body + 1.
-    /// If there a are multiple yields in a scope, the one with the highest number is returned.
+    /// returns `Some(YieldData)`. If not, returns `None`.
     pub fn yield_in_scope(&self, scope: Scope) -> Option<YieldData> {
         self.yield_in_scope.get(&scope).cloned()
     }

compiler/rustc_middle/src/ty/inhabitedness/def_id_forest.rs

@@ -17,7 +17,7 @@ pub struct DefIdForest {
     /// If A and B are DefIds in the `DefIdForest`, and A is a descendant
     /// of B, then only B will be in `root_ids`.
     /// We use a `SmallVec` here because (for its use for caching inhabitedness)
-    /// its rare that this will contain even two IDs.
+    /// it's rare that this will contain even two IDs.
     root_ids: SmallVec<[DefId; 1]>,
 }
 

compiler/rustc_middle/src/ty/mod.rs

@@ -1,3 +1,14 @@
+//! Defines how the compiler represents types internally.
+//!
+//! Two important entities in this module are:
+//!
+//! - [`rustc_middle::ty::Ty`], used to represent the semantics of a type.
+//! - [`rustc_middle::ty::TyCtxt`], the central data structure in the compiler.
+//!
+//! For more information, see ["The `ty` module: representing types"] in the ructc-dev-guide.
+//!
+//! ["The `ty` module: representing types"]: https://rustc-dev-guide.rust-lang.org/ty.html
+
 // ignore-tidy-filelength
 pub use self::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 pub use self::AssocItemContainer::*;

compiler/rustc_middle/src/ty/query/on_disk_cache.rs

@@ -666,7 +666,7 @@ impl<'sess> OnDiskCache<'sess> {
 
 //- DECODING -------------------------------------------------------------------
 
-/// A decoder that can read from the incr. comp. cache. It is similar to the one
+/// A decoder that can read from the incremental compilation cache. It is similar to the one
 /// we use for crate metadata decoding in that it can rebase spans and eventually
 /// will also handle things that contain `Ty` instances.
 crate struct CacheDecoder<'a, 'tcx> {
@@ -954,7 +954,7 @@ impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [Span] {
 
 //- ENCODING -------------------------------------------------------------------
 
-/// An encoder that can write the incr. comp. cache.
+/// An encoder that can write to the incremental compilation cache.
 struct CacheEncoder<'a, 'tcx, E: OpaqueEncoder> {
     tcx: TyCtxt<'tcx>,
     encoder: &'a mut E,

compiler/rustc_middle/src/ty/sty.rs

@@ -1572,17 +1572,11 @@ impl RegionKind {
     }
 
     pub fn is_late_bound(&self) -> bool {
-        match *self {
-            ty::ReLateBound(..) => true,
-            _ => false,
-        }
+        matches!(*self, ty::ReLateBound(..))
     }
 
     pub fn is_placeholder(&self) -> bool {
-        match *self {
-            ty::RePlaceholder(..) => true,
-            _ => false,
-        }
+        matches!(*self, ty::RePlaceholder(..))
     }
 
     pub fn bound_at_or_above_binder(&self, index: ty::DebruijnIndex) -> bool {

compiler/rustc_span/src/symbol.rs

@@ -13,7 +13,7 @@ use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::str;
 
-use crate::{Span, DUMMY_SP, SESSION_GLOBALS};
+use crate::{Edition, Span, DUMMY_SP, SESSION_GLOBALS};
 
 #[cfg(test)]
 mod tests;
@@ -1609,12 +1609,32 @@ pub mod sym {
 }
 
 impl Symbol {
-    fn is_used_keyword_2018(self) -> bool {
-        self >= kw::Async && self <= kw::Dyn
+    fn is_special(self) -> bool {
+        self <= kw::Underscore
     }
 
-    fn is_unused_keyword_2018(self) -> bool {
-        self == kw::Try
+    fn is_used_keyword_always(self) -> bool {
+        self >= kw::As && self <= kw::While
+    }
+
+    fn is_used_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
+        (self >= kw::Async && self <= kw::Dyn) && edition() >= Edition::Edition2018
+    }
+
+    fn is_unused_keyword_always(self) -> bool {
+        self >= kw::Abstract && self <= kw::Yield
+    }
+
+    fn is_unused_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
+        self == kw::Try && edition() >= Edition::Edition2018
+    }
+
+    pub fn is_reserved(self, edition: impl Copy + FnOnce() -> Edition) -> bool {
+        self.is_special()
+            || self.is_used_keyword_always()
+            || self.is_unused_keyword_always()
+            || self.is_used_keyword_conditional(edition)
+            || self.is_unused_keyword_conditional(edition)
     }
 
     /// A keyword or reserved identifier that can be used as a path segment.
@@ -1642,26 +1662,27 @@ impl Ident {
     // Returns `true` for reserved identifiers used internally for elided lifetimes,
     // unnamed method parameters, crate root module, error recovery etc.
     pub fn is_special(self) -> bool {
-        self.name <= kw::Underscore
+        self.name.is_special()
     }
 
     /// Returns `true` if the token is a keyword used in the language.
     pub fn is_used_keyword(self) -> bool {
         // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
-        self.name >= kw::As && self.name <= kw::While
-            || self.name.is_used_keyword_2018() && self.span.rust_2018()
+        self.name.is_used_keyword_always()
+            || self.name.is_used_keyword_conditional(|| self.span.edition())
     }
 
     /// Returns `true` if the token is a keyword reserved for possible future use.
     pub fn is_unused_keyword(self) -> bool {
         // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
-        self.name >= kw::Abstract && self.name <= kw::Yield
-            || self.name.is_unused_keyword_2018() && self.span.rust_2018()
+        self.name.is_unused_keyword_always()
+            || self.name.is_unused_keyword_conditional(|| self.span.edition())
     }
 
     /// Returns `true` if the token is either a special identifier or a keyword.
     pub fn is_reserved(self) -> bool {
-        self.is_special() || self.is_used_keyword() || self.is_unused_keyword()
+        // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
+        self.name.is_reserved(|| self.span.edition())
     }
 
     /// A keyword or reserved identifier that can be used as a path segment.
@@ -1681,7 +1702,7 @@ fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
     SESSION_GLOBALS.with(|session_globals| f(&mut *session_globals.symbol_interner.lock()))
 }
 
-/// An alternative to `Symbol`, useful when the chars within the symbol need to
+/// An alternative to [`Symbol`], useful when the chars within the symbol need to
 /// be accessed. It deliberately has limited functionality and should only be
 /// used for temporary values.
 ///

compiler/rustc_typeck/src/check/demand.rs

@@ -360,10 +360,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         false
     }
 
-    fn replace_prefix(&self, s: &str, old: &str, new: &str) -> Option<String> {
-        s.strip_prefix(old).map(|stripped| new.to_string() + stripped)
-    }
-
     /// This function is used to determine potential "simple" improvements or users' errors and
     /// provide them useful help. For example:
     ///
@@ -394,6 +390,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return None;
         }
 
+        let replace_prefix = |s: &str, old: &str, new: &str| {
+            s.strip_prefix(old).map(|stripped| new.to_string() + stripped)
+        };
+
         let is_struct_pat_shorthand_field =
             self.is_hir_id_from_struct_pattern_shorthand_field(expr.hir_id, sp);
 
@@ -409,7 +409,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 (&ty::Str, &ty::Array(arr, _) | &ty::Slice(arr)) if arr == self.tcx.types.u8 => {
                     if let hir::ExprKind::Lit(_) = expr.kind {
                         if let Ok(src) = sm.span_to_snippet(sp) {
-                            if let Some(src) = self.replace_prefix(&src, "b\"", "\"") {
+                            if let Some(src) = replace_prefix(&src, "b\"", "\"") {
                                 return Some((
                                     sp,
                                     "consider removing the leading `b`",
@@ -423,7 +423,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 (&ty::Array(arr, _) | &ty::Slice(arr), &ty::Str) if arr == self.tcx.types.u8 => {
                     if let hir::ExprKind::Lit(_) = expr.kind {
                         if let Ok(src) = sm.span_to_snippet(sp) {
-                            if let Some(src) = self.replace_prefix(&src, "\"", "b\"") {
+                            if let Some(src) = replace_prefix(&src, "\"", "b\"") {
                                 return Some((
                                     sp,
                                     "consider adding a leading `b`",
@@ -583,23 +583,27 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 hir::Mutability::Mut => {
                                     let new_prefix = "&mut ".to_owned() + derefs;
                                     match mutbl_a {
-                                        hir::Mutability::Mut => self
-                                            .replace_prefix(&src, "&mut ", &new_prefix)
-                                            .map(|s| (s, Applicability::MachineApplicable)),
-                                        hir::Mutability::Not => self
-                                            .replace_prefix(&src, "&", &new_prefix)
-                                            .map(|s| (s, Applicability::Unspecified)),
+                                        hir::Mutability::Mut => {
+                                            replace_prefix(&src, "&mut ", &new_prefix)
+                                                .map(|s| (s, Applicability::MachineApplicable))
+                                        }
+                                        hir::Mutability::Not => {
+                                            replace_prefix(&src, "&", &new_prefix)
+                                                .map(|s| (s, Applicability::Unspecified))
+                                        }
                                     }
                                 }
                                 hir::Mutability::Not => {
                                     let new_prefix = "&".to_owned() + derefs;
                                     match mutbl_a {
-                                        hir::Mutability::Mut => self
-                                            .replace_prefix(&src, "&mut ", &new_prefix)
-                                            .map(|s| (s, Applicability::MachineApplicable)),
-                                        hir::Mutability::Not => self
-                                            .replace_prefix(&src, "&", &new_prefix)
-                                            .map(|s| (s, Applicability::MachineApplicable)),
+                                        hir::Mutability::Mut => {
+                                            replace_prefix(&src, "&mut ", &new_prefix)
+                                                .map(|s| (s, Applicability::MachineApplicable))
+                                        }
+                                        hir::Mutability::Not => {
+                                            replace_prefix(&src, "&", &new_prefix)
+                                                .map(|s| (s, Applicability::MachineApplicable))
+                                        }
                                     }
                                 }
                             } {

library/rustc-std-workspace-core/README.md

@@ -4,12 +4,12 @@ This crate is a shim and empty crate which simply depends on `libcore` and
 reexports all of its contents. The crate is the crux of empowering the standard
 library to depend on crates from crates.io
 
-Crates on crates.io that the standard library depend on the
-`rustc-std-workspace-core` crate from crates.io. On crates.io, however, this
-crate is empty. We use `[patch]` to override it to this crate in this
-repository. As a result, crates on crates.io will draw a dependency edge to
-`libcore`, the version defined in this repository. That should draw all the
-dependency edges to ensure Cargo builds crates successfully!
+Crates on crates.io that the standard library depend on need to depend on the
+`rustc-std-workspace-core` crate from crates.io, which is empty. We use
+`[patch]` to override it to this crate in this repository. As a result, crates
+on crates.io will draw a dependency edge to `libcore`, the version defined in
+this repository. That should draw all the dependency edges to ensure Cargo
+builds crates successfully!
 
 Note that crates on crates.io need to depend on this crate with the name `core`
 for everything to work correctly. To do that they can use: