Fix typos “a”→“an”

compiler/rustc_ast/src/token.rs

@@ -495,7 +495,7 @@ impl Token {
         self.lifetime().is_some()
     }
 
-    /// Returns `true` if the token is a identifier whose name is the given
+    /// Returns `true` if the token is an identifier whose name is the given
     /// string slice.
     pub fn is_ident_named(&self, name: Symbol) -> bool {
         self.ident().map_or(false, |(ident, _)| ident.name == name)

compiler/rustc_ast_lowering/src/lib.rs

@@ -1265,7 +1265,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                     ty,
                                 );
 
-                                // Construct a AnonConst where the expr is the "ty"'s path.
+                                // Construct an AnonConst where the expr is the "ty"'s path.
 
                                 let parent_def_id = self.current_hir_id_owner.0;
                                 let node_id = self.resolver.next_node_id();
@@ -2690,7 +2690,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     /// Report an error on illegal use of `'_` or a `&T` with no explicit lifetime;
-    /// return a "error lifetime".
+    /// return an "error lifetime".
     fn new_error_lifetime(&mut self, id: Option<NodeId>, span: Span) -> hir::Lifetime {
         let (id, msg, label) = match id {
             Some(id) => (id, "`'_` cannot be used here", "`'_` is a reserved lifetime name"),

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

@@ -1700,7 +1700,7 @@ where
 /// One or more fields: call the base case function on the first value (which depends on
 /// `use_fold`), and use that as the base case. Then perform `cs_fold` on the remainder of the
 /// fields.
-/// When the `substructure` is a `EnumNonMatchingCollapsed`, the result of `enum_nonmatch_f`
+/// When the `substructure` is an `EnumNonMatchingCollapsed`, the result of `enum_nonmatch_f`
 /// is returned. Statics may not be folded over.
 /// See `cs_op` in `partial_ord.rs` for a model example.
 pub fn cs_fold1<F, B>(

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -137,7 +137,7 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
                         match scalar.value {
                             Primitive::Int(..) => {
                                 if self.cx().size_of(ret_ty).bytes() < 4 {
-                                    // `va_arg` should not be called on a integer type
+                                    // `va_arg` should not be called on an integer type
                                     // less than 4 bytes in length. If it is, promote
                                     // the integer to a `i32` and truncate the result
                                     // back to the smaller type.

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -901,7 +901,7 @@ fn cast_float_to_int<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     //
     // Performance note: Unordered comparison can be lowered to a "flipped"
     // comparison and a negation, and the negation can be merged into the
-    // select. Therefore, it not necessarily any more expensive than a
+    // select. Therefore, it not necessarily any more expensive than an
     // ordered ("normal") comparison. Whether these optimizations will be
     // performed is ultimately up to the backend, but at least x86 does
     // perform them.

compiler/rustc_data_structures/src/owning_ref/mod.rs

@@ -321,7 +321,7 @@ pub unsafe trait IntoErasedSendSync<'a> {
 /////////////////////////////////////////////////////////////////////////////
 
 impl<O, T: ?Sized> OwningRef<O, T> {
-    /// Creates a new owning reference from a owner
+    /// Creates a new owning reference from an owner
     /// initialized to the direct dereference of it.
     ///
     /// # Example
@@ -368,7 +368,7 @@ impl<O, T: ?Sized> OwningRef<O, T> {
     /// fn main() {
     ///     let owning_ref = OwningRef::new(Box::new([1, 2, 3, 4]));
     ///
-    ///     // create a owning reference that points at the
+    ///     // create an owning reference that points at the
     ///     // third element of the array.
     ///     let owning_ref = owning_ref.map(|array| &array[2]);
     ///     assert_eq!(*owning_ref, 3);
@@ -396,7 +396,7 @@ impl<O, T: ?Sized> OwningRef<O, T> {
     /// fn main() {
     ///     let owning_ref = OwningRef::new(Box::new([1, 2, 3, 4]));
     ///
-    ///     // create a owning reference that points at the
+    ///     // create an owning reference that points at the
     ///     // third element of the array.
     ///     let owning_ref = owning_ref.try_map(|array| {
     ///         if array[2] == 3 { Ok(&array[2]) } else { Err(()) }
@@ -430,7 +430,7 @@ impl<O, T: ?Sized> OwningRef<O, T> {
     /// in an additional `Box<O>`.
     ///
     /// This can be used to safely erase the owner of any `OwningRef<O, T>`
-    /// to a `OwningRef<Box<Erased>, T>`.
+    /// to an `OwningRef<Box<Erased>, T>`.
     pub fn map_owner_box(self) -> OwningRef<Box<O>, T> {
         OwningRef { reference: self.reference, owner: Box::new(self.owner) }
     }
@@ -511,7 +511,7 @@ impl<O, T: ?Sized> OwningRef<O, T> {
 }
 
 impl<O, T: ?Sized> OwningRefMut<O, T> {
-    /// Creates a new owning reference from a owner
+    /// Creates a new owning reference from an owner
     /// initialized to the direct dereference of it.
     ///
     /// # Example
@@ -558,7 +558,7 @@ impl<O, T: ?Sized> OwningRefMut<O, T> {
     /// fn main() {
     ///     let owning_ref_mut = OwningRefMut::new(Box::new([1, 2, 3, 4]));
     ///
-    ///     // create a owning reference that points at the
+    ///     // create an owning reference that points at the
     ///     // third element of the array.
     ///     let owning_ref = owning_ref_mut.map(|array| &array[2]);
     ///     assert_eq!(*owning_ref, 3);
@@ -586,7 +586,7 @@ impl<O, T: ?Sized> OwningRefMut<O, T> {
     /// fn main() {
     ///     let owning_ref_mut = OwningRefMut::new(Box::new([1, 2, 3, 4]));
     ///
-    ///     // create a owning reference that points at the
+    ///     // create an owning reference that points at the
     ///     // third element of the array.
     ///     let owning_ref_mut = owning_ref_mut.map_mut(|array| &mut array[2]);
     ///     assert_eq!(*owning_ref_mut, 3);
@@ -614,7 +614,7 @@ impl<O, T: ?Sized> OwningRefMut<O, T> {
     /// fn main() {
     ///     let owning_ref_mut = OwningRefMut::new(Box::new([1, 2, 3, 4]));
     ///
-    ///     // create a owning reference that points at the
+    ///     // create an owning reference that points at the
     ///     // third element of the array.
     ///     let owning_ref = owning_ref_mut.try_map(|array| {
     ///         if array[2] == 3 { Ok(&array[2]) } else { Err(()) }
@@ -644,7 +644,7 @@ impl<O, T: ?Sized> OwningRefMut<O, T> {
     /// fn main() {
     ///     let owning_ref_mut = OwningRefMut::new(Box::new([1, 2, 3, 4]));
     ///
-    ///     // create a owning reference that points at the
+    ///     // create an owning reference that points at the
     ///     // third element of the array.
     ///     let owning_ref_mut = owning_ref_mut.try_map_mut(|array| {
     ///         if array[2] == 3 { Ok(&mut array[2]) } else { Err(()) }
@@ -678,7 +678,7 @@ impl<O, T: ?Sized> OwningRefMut<O, T> {
     /// in an additional `Box<O>`.
     ///
     /// This can be used to safely erase the owner of any `OwningRefMut<O, T>`
-    /// to a `OwningRefMut<Box<Erased>, T>`.
+    /// to an `OwningRefMut<Box<Erased>, T>`.
     pub fn map_owner_box(self) -> OwningRefMut<Box<O>, T> {
         OwningRefMut { reference: self.reference, owner: Box::new(self.owner) }
     }
@@ -970,7 +970,7 @@ where
     }
 }
 
-// ^ FIXME: Is a Into impl for calling into_inner() possible as well?
+// ^ FIXME: Is an Into impl for calling into_inner() possible as well?
 
 impl<O, T: ?Sized> Debug for OwningRef<O, T>
 where
@@ -1139,27 +1139,27 @@ impl<T: 'static> ToHandleMut for RefCell<T> {
 // about which handle creation to use (i.e., read() vs try_read()) as well as
 // what to do with error results.
 
-/// Typedef of a owning reference that uses a `Box` as the owner.
+/// Typedef of an owning reference that uses a `Box` as the owner.
 pub type BoxRef<T, U = T> = OwningRef<Box<T>, U>;
-/// Typedef of a owning reference that uses a `Vec` as the owner.
+/// Typedef of an owning reference that uses a `Vec` as the owner.
 pub type VecRef<T, U = T> = OwningRef<Vec<T>, U>;
-/// Typedef of a owning reference that uses a `String` as the owner.
+/// Typedef of an owning reference that uses a `String` as the owner.
 pub type StringRef = OwningRef<String, str>;
 
-/// Typedef of a owning reference that uses a `Rc` as the owner.
+/// Typedef of an owning reference that uses a `Rc` as the owner.
 pub type RcRef<T, U = T> = OwningRef<Rc<T>, U>;
-/// Typedef of a owning reference that uses a `Arc` as the owner.
+/// Typedef of an owning reference that uses a `Arc` as the owner.
 pub type ArcRef<T, U = T> = OwningRef<Arc<T>, U>;
 
-/// Typedef of a owning reference that uses a `Ref` as the owner.
+/// Typedef of an owning reference that uses a `Ref` as the owner.
 pub type RefRef<'a, T, U = T> = OwningRef<Ref<'a, T>, U>;
-/// Typedef of a owning reference that uses a `RefMut` as the owner.
+/// Typedef of an owning reference that uses a `RefMut` as the owner.
 pub type RefMutRef<'a, T, U = T> = OwningRef<RefMut<'a, T>, U>;
-/// Typedef of a owning reference that uses a `MutexGuard` as the owner.
+/// Typedef of an owning reference that uses a `MutexGuard` as the owner.
 pub type MutexGuardRef<'a, T, U = T> = OwningRef<MutexGuard<'a, T>, U>;
-/// Typedef of a owning reference that uses a `RwLockReadGuard` as the owner.
+/// Typedef of an owning reference that uses a `RwLockReadGuard` as the owner.
 pub type RwLockReadGuardRef<'a, T, U = T> = OwningRef<RwLockReadGuard<'a, T>, U>;
-/// Typedef of a owning reference that uses a `RwLockWriteGuard` as the owner.
+/// Typedef of an owning reference that uses a `RwLockWriteGuard` as the owner.
 pub type RwLockWriteGuardRef<'a, T, U = T> = OwningRef<RwLockWriteGuard<'a, T>, U>;
 
 /// Typedef of a mutable owning reference that uses a `Box` as the owner.
@@ -1219,11 +1219,11 @@ unsafe impl<'a, T: Send + Sync + 'a> IntoErasedSendSync<'a> for Arc<T> {
     }
 }
 
-/// Typedef of a owning reference that uses an erased `Box` as the owner.
+/// Typedef of an owning reference that uses an erased `Box` as the owner.
 pub type ErasedBoxRef<U> = OwningRef<Box<dyn Erased>, U>;
-/// Typedef of a owning reference that uses an erased `Rc` as the owner.
+/// Typedef of an owning reference that uses an erased `Rc` as the owner.
 pub type ErasedRcRef<U> = OwningRef<Rc<dyn Erased>, U>;
-/// Typedef of a owning reference that uses an erased `Arc` as the owner.
+/// Typedef of an owning reference that uses an erased `Arc` as the owner.
 pub type ErasedArcRef<U> = OwningRef<Arc<dyn Erased>, U>;
 
 /// Typedef of a mutable owning reference that uses an erased `Box` as the owner.

compiler/rustc_data_structures/src/profiling.rs

@@ -220,7 +220,7 @@ impl SelfProfilerRef {
         VerboseTimingGuard::start(message, self.generic_activity(event_label))
     }
 
-    /// Start profiling a extra verbose generic activity. Profiling continues until the
+    /// Start profiling an extra verbose generic activity. Profiling continues until the
     /// VerboseTimingGuard returned from this call is dropped. In addition to recording
     /// a measureme event, "extra verbose" generic activities also print a timing entry to
     /// stdout if the compiler is invoked with -Ztime-passes.

compiler/rustc_data_structures/src/sync.rs

@@ -14,7 +14,7 @@
 //!
 //! `MTRef` is an immutable reference if cfg!(parallel_compiler), and a mutable reference otherwise.
 //!
-//! `rustc_erase_owner!` erases a OwningRef owner into Erased or Erased + Send + Sync
+//! `rustc_erase_owner!` erases an OwningRef owner into Erased or Erased + Send + Sync
 //! depending on the value of cfg!(parallel_compiler).
 
 use crate::owning_ref::{Erased, OwningRef};

compiler/rustc_data_structures/src/tiny_list.rs

@@ -5,7 +5,7 @@
 //!
 //! - If you have a list that rarely stores more than one element, then this
 //!   data-structure can store the element without allocating and only uses as
-//!   much space as a `Option<(T, usize)>`. If T can double as the `Option`
+//!   much space as an `Option<(T, usize)>`. If T can double as the `Option`
 //!   discriminant, it will even only be as large as `T, usize`.
 //!
 //! If you expect to store more than 1 element in the common case, steer clear

compiler/rustc_hir/src/hir.rs

@@ -2323,7 +2323,7 @@ pub enum TyKind<'hir> {
     ///
     /// Type parameters may be stored in each `PathSegment`.
     Path(QPath<'hir>),
-    /// A opaque type definition itself. This is currently only used for the
+    /// An opaque type definition itself. This is currently only used for the
     /// `opaque type Foo: Trait` item that `impl Trait` in desugars to.
     ///
     /// The generic argument list contains the lifetimes (and in the future

compiler/rustc_hir/src/intravisit.rs

@@ -313,7 +313,7 @@ pub trait Visitor<'v>: Sized {
     }
 
     /// When invoking `visit_all_item_likes()`, you need to supply an
-    /// item-like visitor. This method converts a "intra-visit"
+    /// item-like visitor. This method converts an "intra-visit"
     /// visitor into an item-like visitor that walks the entire tree.
     /// If you use this, you probably don't want to process the
     /// contents of nested item-like things, since the outer loop will

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -1697,7 +1697,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         }
 
         // In some (most?) cases cause.body_id points to actual body, but in some cases
-        // it's a actual definition. According to the comments (e.g. in
+        // it's an actual definition. According to the comments (e.g. in
         // librustc_typeck/check/compare_method.rs:compare_predicate_entailment) the latter
         // is relied upon by some other code. This might (or might not) need cleanup.
         let body_owner_def_id =

compiler/rustc_infer/src/infer/nll_relate/mod.rs

@@ -389,7 +389,7 @@ where
     }
 }
 
-/// When we instantiate a inference variable with a value in
+/// When we instantiate an inference variable with a value in
 /// `relate_ty_var`, we always have the pair of a `TyVid` and a `Ty`,
 /// but the ordering may vary (depending on whether the inference
 /// variable was found on the `a` or `b` sides). Therefore, this trait

compiler/rustc_infer/src/infer/region_constraints/mod.rs

@@ -186,7 +186,7 @@ pub enum GenericKind<'tcx> {
 ///        ('a: min) || ('b: min)
 ///     }
 ///
-/// This is described with a `AnyRegion('a, 'b)` node.
+/// This is described with an `AnyRegion('a, 'b)` node.
 #[derive(Debug, Clone)]
 pub enum VerifyBound<'tcx> {
     /// Given a kind K and a bound B, expands to a function like the

compiler/rustc_infer/src/traits/mod.rs

@@ -28,7 +28,7 @@ pub use self::project::{
 pub use rustc_middle::traits::*;
 
 /// An `Obligation` represents some trait reference (e.g., `i32: Eq`) for
-/// which the "impl_source" must be found. The process of finding a "impl_source" is
+/// which the "impl_source" must be found. The process of finding an "impl_source" is
 /// called "resolving" the `Obligation`. This process consists of
 /// either identifying an `impl` (e.g., `impl Eq for i32`) that
 /// satisfies the obligation, or else finding a bound that is in

compiler/rustc_lint/src/types.rs

@@ -1171,7 +1171,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
                     ty::Projection(..) => {
                         let ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, ty);
 
-                        // If `ty` is a opaque type directly then `super_visit_with` won't invoke
+                        // If `ty` is an opaque type directly then `super_visit_with` won't invoke
                         // this function again.
                         if ty.has_opaque_types() {
                             self.visit_ty(ty)

compiler/rustc_metadata/src/creader.rs

@@ -308,7 +308,7 @@ impl<'a> CrateLoader<'a> {
             }
 
             // Alright, so we've gotten this far which means that `data` has the
-            // right name, we don't have a hash, and we don't have a --extern
+            // right name, we don't have a hash, and we don't have an --extern
             // pointing for ourselves. We're still not quite yet done because we
             // have to make sure that this crate was found in the crate lookup
             // path (this is a top-level dependency) as we don't want to

compiler/rustc_middle/src/hir/map/blocks.rs

@@ -63,7 +63,7 @@ impl MaybeFnLike for hir::Expr<'_> {
     }
 }
 
-/// Carries either an FnLikeNode or a Expr, as these are the two
+/// Carries either an FnLikeNode or an Expr, as these are the two
 /// constructs that correspond to "code" (as in, something from which
 /// we can construct a control-flow graph).
 #[derive(Copy, Clone)]

compiler/rustc_middle/src/middle/region.rs

@@ -151,7 +151,7 @@ rustc_index::newtype_index! {
 static_assert_size!(ScopeData, 4);
 
 impl Scope {
-    /// Returns a item-local ID associated with this scope.
+    /// Returns an item-local ID associated with this scope.
     ///
     /// N.B., likely to be replaced as API is refined; e.g., pnkfelix
     /// anticipates `fn entry_node_id` and `fn each_exit_node_id`.

compiler/rustc_middle/src/mir/interpret/error.rs

@@ -46,7 +46,7 @@ static_assert_size!(InterpErrorInfo<'_>, 8);
 /// Packages the kind of error we got from the const code interpreter
 /// up with a Rust-level backtrace of where the error occurred.
 /// These should always be constructed by calling `.into()` on
-/// a `InterpError`. In `rustc_mir::interpret`, we have `throw_err_*`
+/// an `InterpError`. In `rustc_mir::interpret`, we have `throw_err_*`
 /// macros for this.
 #[derive(Debug)]
 pub struct InterpErrorInfo<'tcx>(Box<InterpErrorInfoInner<'tcx>>);

compiler/rustc_middle/src/mir/interpret/value.rs

@@ -17,7 +17,7 @@ use super::{
 /// Represents the result of const evaluation via the `eval_to_allocation` query.
 #[derive(Copy, Clone, HashStable, TyEncodable, TyDecodable, Debug, Hash, Eq, PartialEq)]
 pub struct ConstAlloc<'tcx> {
-    // the value lives here, at offset 0, and that allocation definitely is a `AllocKind::Memory`
+    // the value lives here, at offset 0, and that allocation definitely is an `AllocKind::Memory`
     // (so you can use `AllocMap::unwrap_memory`).
     pub alloc_id: AllocId,
     pub ty: Ty<'tcx>,
@@ -113,7 +113,7 @@ impl<'tcx> ConstValue<'tcx> {
 }
 
 /// A `Scalar` represents an immediate, primitive value existing outside of a
-/// `memory::Allocation`. It is in many ways like a small chunk of a `Allocation`, up to 16 bytes in
+/// `memory::Allocation`. It is in many ways like a small chunk of an `Allocation`, up to 16 bytes in
 /// size. Like a range of bytes in an `Allocation`, a `Scalar` can either represent the raw bytes
 /// of a simple value or a pointer into another `Allocation`
 ///

compiler/rustc_middle/src/traits/mod.rs

@@ -509,7 +509,7 @@ pub enum ImplSource<'tcx, N> {
     TraitUpcasting(ImplSourceTraitUpcastingData<'tcx, N>),
 
     /// ImplSource automatically generated for a closure. The `DefId` is the ID
-    /// of the closure expression. This is a `ImplSource::UserDefined` in spirit, but the
+    /// of the closure expression. This is an `ImplSource::UserDefined` in spirit, but the
     /// impl is generated by the compiler and does not appear in the source.
     Closure(ImplSourceClosureData<'tcx, N>),
 

compiler/rustc_middle/src/traits/select.rs

@@ -111,7 +111,7 @@ pub enum SelectionCandidate<'tcx> {
     ProjectionCandidate(usize),
 
     /// Implementation of a `Fn`-family trait by one of the anonymous types
-    /// generated for a `||` expression.
+    /// generated for an `||` expression.
     ClosureCandidate,
 
     /// Implementation of a `Generator` trait by one of the anonymous types

compiler/rustc_middle/src/ty/adt.rs

@@ -209,7 +209,7 @@ impl<'tcx> AdtDef {
         self.flags.contains(AdtFlags::IS_UNION)
     }
 
-    /// Returns `true` if this is a enum.
+    /// Returns `true` if this is an enum.
     #[inline]
     pub fn is_enum(&self) -> bool {
         self.flags.contains(AdtFlags::IS_ENUM)

compiler/rustc_middle/src/ty/context.rs

@@ -1792,7 +1792,7 @@ pub mod tls {
         if context == 0 {
             f(None)
         } else {
-            // We could get a `ImplicitCtxt` pointer from another thread.
+            // We could get an `ImplicitCtxt` pointer from another thread.
             // Ensure that `ImplicitCtxt` is `Sync`.
             sync::assert_sync::<ImplicitCtxt<'_, '_>>();
 

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

@@ -9,7 +9,7 @@ use crate::ty::{DefId, SubstsRef};
 
 mod def_id_forest;
 
-// The methods in this module calculate `DefIdForest`s of modules in which a
+// The methods in this module calculate `DefIdForest`s of modules in which an
 // `AdtDef`/`VariantDef`/`FieldDef` is visibly uninhabited.
 //
 // # Example