Fix misuses of a vs an

Signed-off-by: cui fliter <imcusg@gmail.com>

compiler/rustc_ast/src/token.rs

@@ -446,7 +446,7 @@ impl Token {
         }
     }
 
-    /// Returns `true` if the token can appear at the start of an pattern.
+    /// Returns `true` if the token can appear at the start of a pattern.
     ///
     /// Shamelessly borrowed from `can_begin_expr`, only used for diagnostics right now.
     pub fn can_begin_pattern(&self) -> bool {

compiler/rustc_attr/src/builtin.rs

@@ -162,7 +162,7 @@ pub enum StabilityLevel {
         is_soft: bool,
         /// If part of a feature is stabilized and a new feature is added for the remaining parts,
         /// then the `implied_by` attribute is used to indicate which now-stable feature previously
-        /// contained a item.
+        /// contained an item.
         ///
         /// ```pseudo-Rust
         /// #[unstable(feature = "foo", issue = "...")]

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -1364,7 +1364,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     err.note(format!(
                         "a for loop advances the iterator for you, the result is stored in `{loop_bind}`."
                     ));
-                    err.help("if you want to call `next` on a iterator within the loop, consider using `while let`.");
+                    err.help("if you want to call `next` on an iterator within the loop, consider using `while let`.");
         }
     }
 

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -1358,9 +1358,9 @@ fn suggest_ampmut<'tcx>(
         None => (false, decl_span),
     };
 
-    // if the binding already exists and is a reference with a explicit
+    // if the binding already exists and is a reference with an explicit
     // lifetime, then we can suggest adding ` mut`. this is special-cased from
-    // the path without a explicit lifetime.
+    // the path without an explicit lifetime.
     if let Ok(src) = tcx.sess.source_map().span_to_snippet(span)
         && src.starts_with("&'")
         // note that `&     'a T` is invalid so this is correct.

compiler/rustc_borrowck/src/lib.rs

@@ -1966,7 +1966,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             Reservation(WriteKind::MutableBorrow(BorrowKind::Mut { kind: mut_borrow_kind }))
             | Write(WriteKind::MutableBorrow(BorrowKind::Mut { kind: mut_borrow_kind })) => {
                 let is_local_mutation_allowed = match mut_borrow_kind {
-                    // `ClosureCapture` is used for mutable variable with a immutable binding.
+                    // `ClosureCapture` is used for mutable variable with an immutable binding.
                     // This is only behaviour difference between `ClosureCapture` and mutable borrows.
                     MutBorrowKind::ClosureCapture => LocalMutationIsAllowed::Yes,
                     MutBorrowKind::Default | MutBorrowKind::TwoPhaseBorrow => {

compiler/rustc_borrowck/src/universal_regions.rs

@@ -164,7 +164,7 @@ struct UniversalRegionIndices<'tcx> {
     /// be able to map them to our internal `RegionVid`. This is
     /// basically equivalent to an `GenericArgs`, except that it also
     /// contains an entry for `ReStatic` -- it might be nice to just
-    /// use a args, and then handle `ReStatic` another way.
+    /// use an args, and then handle `ReStatic` another way.
     indices: FxHashMap<ty::Region<'tcx>, RegionVid>,
 
     /// The vid assigned to `'static`. Used only for diagnostics.
@@ -290,7 +290,7 @@ impl<'tcx> UniversalRegions<'tcx> {
         (FIRST_GLOBAL_INDEX..self.num_universals).map(RegionVid::from_usize)
     }
 
-    /// Returns `true` if `r` is classified as an local region.
+    /// Returns `true` if `r` is classified as a local region.
     pub fn is_local_free_region(&self, r: RegionVid) -> bool {
         self.region_classification(r) == Some(RegionClassification::Local)
     }

compiler/rustc_codegen_cranelift/src/abi/mod.rs

@@ -30,7 +30,7 @@ fn clif_sig_from_fn_abi<'tcx>(
     let inputs = fn_abi.args.iter().flat_map(|arg_abi| arg_abi.get_abi_param(tcx).into_iter());
 
     let (return_ptr, returns) = fn_abi.ret.get_abi_return(tcx);
-    // Sometimes the first param is an pointer to the place where the return value needs to be stored.
+    // Sometimes the first param is a pointer to the place where the return value needs to be stored.
     let params: Vec<_> = return_ptr.into_iter().chain(inputs).collect();
 
     Signature { params, returns, call_conv }

compiler/rustc_codegen_llvm/src/type_.rs

@@ -112,7 +112,7 @@ impl<'ll> CodegenCx<'ll, '_> {
         }
     }
 
-    /// Return a LLVM type that has at most the required alignment,
+    /// Return an LLVM type that has at most the required alignment,
     /// and exactly the required size, as a best-effort padding array.
     pub(crate) fn type_padding_filler(&self, size: Size, align: Align) -> &'ll Type {
         let unit = Integer::approximate_align(self, align);

compiler/rustc_codegen_ssa/src/traits/type_.rs

@@ -30,7 +30,7 @@ pub trait BaseTypeMethods<'tcx>: Backend<'tcx> {
     fn type_ptr_ext(&self, address_space: AddressSpace) -> Self::Type;
     fn element_type(&self, ty: Self::Type) -> Self::Type;
 
-    /// Returns the number of elements in `self` if it is a LLVM vector type.
+    /// Returns the number of elements in `self` if it is an LLVM vector type.
     fn vector_length(&self, ty: Self::Type) -> usize;
 
     fn float_width(&self, ty: Self::Type) -> usize;

compiler/rustc_mir_build/src/build/expr/mod.rs

@@ -44,7 +44,7 @@
 //! the most suitable spot to implement it, and then just let the
 //! other fns cycle around. The handoff works like this:
 //!
-//! - `into(place)` -> fallback is to create a rvalue with `as_rvalue` and assign it to `place`
+//! - `into(place)` -> fallback is to create an rvalue with `as_rvalue` and assign it to `place`
 //! - `as_rvalue` -> fallback is to create an Operand with `as_operand` and use `Rvalue::use`
 //! - `as_operand` -> either invokes `as_constant` or `as_temp`
 //! - `as_constant` -> (no fallback)

compiler/rustc_ty_utils/src/abi.rs

@@ -528,7 +528,7 @@ fn fn_abi_adjust_for_abi<'tcx>(
                 arg.make_indirect();
             } else {
                 // We want to pass small aggregates as immediates, but using
-                // a LLVM aggregate type for this leads to bad optimizations,
+                // an LLVM aggregate type for this leads to bad optimizations,
                 // so we pick an appropriately sized integer type instead.
                 arg.cast_to(Reg { kind: RegKind::Integer, size });
             }

library/alloc/src/collections/btree/dedup_sorted_iter.rs

@@ -1,6 +1,6 @@
 use core::iter::Peekable;
 
-/// A iterator for deduping the key of a sorted iterator.
+/// An iterator for deduping the key of a sorted iterator.
 /// When encountering the duplicated key, only the last key-value pair is yielded.
 ///
 /// Used by [`BTreeMap::bulk_build_from_sorted_iter`][1].

src/doc/rustc/src/platform-support/mips-release-6.md

@@ -67,7 +67,7 @@ The following procedure outlines the build process for the MIPS64 R6 target with
 
 ### Prerequisite: Disable debuginfo
 
-A LLVM bug makes rustc crash if debug or debug info generation is enabled. You need to edit `config.toml` to disable this:
+An LLVM bug makes rustc crash if debug or debug info generation is enabled. You need to edit `config.toml` to disable this:
 
 ```toml
 [rust]

tests/ui/codegen/issue-79865-llvm-miscompile.rs

@@ -4,7 +4,7 @@
 
 // Regression test for issue #79865.
 // The assertion will fail when compiled with Rust 1.56..=1.59
-// due to a LLVM miscompilation.
+// due to an LLVM miscompilation.
 
 use std::arch::x86_64::*;
 

tests/ui/consts/const-adt-align-mismatch.rs

@@ -12,7 +12,7 @@ enum Foo {
 }
 
 // NOTE(eddyb) Don't make this a const, needs to be a static
-// so it is always instantiated as a LLVM constant value.
+// so it is always instantiated as an LLVM constant value.
 static FOO: Foo = Foo::C;
 
 fn main() {

tests/ui/debuginfo/sroa-fragment-debuginfo.rs

@@ -1,4 +1,4 @@
-// Verify that we do not trigger a LLVM assertion by creating zero-sized DWARF fragments.
+// Verify that we do not trigger an LLVM assertion by creating zero-sized DWARF fragments.
 //
 // build-pass
 // compile-flags: -g -Zmir-opt-level=0 -Zmir-enable-passes=+ScalarReplacementOfAggregates