Auto merge of #88265 - m-ou-se:rollup-soymv20, r=m-ou-se

Rollup of 6 pull requests

Successful merges:

 - #87976 (Account for tabs when highlighting multiline code suggestions)
 - #88174 (Clarify some wording in Rust 2021 lint docs)
 - #88188 (Greatly improve limitation handling on parallel rustdoc GUI test run)
 - #88230 (Fix typos “a”→“an”)
 - #88232 (Add notes to macro-not-found diagnostics to point out how things with the same name were not a match.)
 - #88259 (Do not mark `-Z thir-unsafeck` as unsound anymore)

Failed merges:

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

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/builder.rs

@@ -558,7 +558,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
 
     fn range_metadata(&mut self, load: &'ll Value, range: Range<u128>) {
         if self.sess().target.arch == "amdgpu" {
-            // amdgpu/LLVM does something weird and thinks a i64 value is
+            // amdgpu/LLVM does something weird and thinks an i64 value is
             // split into a v2i32, halving the bitwidth LLVM expects,
             // tripping an assertion. So, for now, just disable this
             // optimization.

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -137,9 +137,9 @@ 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
+                                    // the integer to an `i32` and truncate the result
                                     // back to the smaller type.
                                     let promoted_result = emit_va_arg(self, args[0], tcx.types.i32);
                                     self.trunc(promoted_result, llret_ty)
@@ -1031,7 +1031,7 @@ fn generic_simd_intrinsic(
         // vector mask and returns an unsigned integer containing the most
         // significant bit (MSB) of each lane.
 
-        // If the vector has less than 8 lanes, an u8 is returned with zeroed
+        // If the vector has less than 8 lanes, a u8 is returned with zeroed
         // trailing bits.
         let expected_int_bits = in_len.max(8);
         match ret_ty.kind() {

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 an `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_errors/src/emitter.rs

@@ -1623,7 +1623,7 @@ impl EmitterWriter {
             let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
             draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
             let mut lines = complete.lines();
-            for (line_pos, (line, parts)) in
+            for (line_pos, (line, highlight_parts)) in
                 lines.by_ref().zip(highlights).take(MAX_SUGGESTION_HIGHLIGHT_LINES).enumerate()
             {
                 // Print the span column to avoid confusion
@@ -1658,7 +1658,7 @@ impl EmitterWriter {
                     );
                     buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
                 } else if is_multiline {
-                    match &parts[..] {
+                    match &highlight_parts[..] {
                         [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
                             buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
                         }
@@ -1676,17 +1676,25 @@ impl EmitterWriter {
                 // print the suggestion
                 buffer.append(row_num, &replace_tabs(line), Style::NoStyle);
 
-                if is_multiline {
-                    for SubstitutionHighlight { start, end } in parts {
+                // Colorize addition/replacements with green.
+                for &SubstitutionHighlight { start, end } in highlight_parts {
+                    // Account for tabs when highlighting (#87972).
+                    let tabs: usize = line
+                        .chars()
+                        .take(start)
+                        .map(|ch| match ch {
+                            '\t' => 3,
+                            _ => 0,
+                        })
+                        .sum();
                     buffer.set_style_range(
                         row_num,
-                            max_line_num_len + 3 + start,
-                            max_line_num_len + 3 + end,
+                        max_line_num_len + 3 + start + tabs,
+                        max_line_num_len + 3 + end + tabs,
                         Style::Addition,
                         true,
                     );
                 }
-                }
                 row_num += 1;
             }
 
@@ -1723,13 +1731,6 @@ impl EmitterWriter {
                     assert!(underline_start >= 0 && underline_end >= 0);
                     let padding: usize = max_line_num_len + 3;
                     for p in underline_start..underline_end {
-                        // Colorize addition/replacements with green.
-                        buffer.set_style(
-                            row_num - 1,
-                            (padding as isize + p) as usize,
-                            Style::Addition,
-                            true,
-                        );
                         if !show_diff {
                             // If this is a replacement, underline with `^`, if this is an addition
                             // underline with `+`.

compiler/rustc_errors/src/lib.rs

@@ -283,6 +283,9 @@ impl CodeSuggestion {
                 let mut buf = String::new();
 
                 let mut line_highlight = vec![];
+                // We need to keep track of the difference between the existing code and the added
+                // or deleted code in order to point at the correct column *after* substitution.
+                let mut acc = 0;
                 for part in &substitution.parts {
                     let cur_lo = sm.lookup_char_pos(part.span.lo());
                     if prev_hi.line == cur_lo.line {
@@ -290,9 +293,11 @@ impl CodeSuggestion {
                             push_trailing(&mut buf, prev_line.as_ref(), &prev_hi, Some(&cur_lo));
                         while count > 0 {
                             highlights.push(std::mem::take(&mut line_highlight));
+                            acc = 0;
                             count -= 1;
                         }
                     } else {
+                        acc = 0;
                         highlights.push(std::mem::take(&mut line_highlight));
                         let mut count = push_trailing(&mut buf, prev_line.as_ref(), &prev_hi, None);
                         while count > 0 {
@@ -316,18 +321,43 @@ impl CodeSuggestion {
                         }
                     }
                     // Add a whole line highlight per line in the snippet.
+                    let len: isize = part
+                        .snippet
+                        .split('\n')
+                        .next()
+                        .unwrap_or(&part.snippet)
+                        .chars()
+                        .map(|c| match c {
+                            '\t' => 4,
+                            _ => 1,
+                        })
+                        .sum();
                     line_highlight.push(SubstitutionHighlight {
-                        start: cur_lo.col.0,
-                        end: cur_lo.col.0
-                            + part.snippet.split('\n').next().unwrap_or(&part.snippet).len(),
+                        start: (cur_lo.col.0 as isize + acc) as usize,
+                        end: (cur_lo.col.0 as isize + acc + len) as usize,
                     });
-                    for line in part.snippet.split('\n').skip(1) {
-                        highlights.push(std::mem::take(&mut line_highlight));
-                        line_highlight.push(SubstitutionHighlight { start: 0, end: line.len() });
-                    }
                     buf.push_str(&part.snippet);
-                    prev_hi = sm.lookup_char_pos(part.span.hi());
+                    let cur_hi = sm.lookup_char_pos(part.span.hi());
+                    if prev_hi.line == cur_lo.line {
+                        // Account for the difference between the width of the current code and the
+                        // snippet being suggested, so that the *later* suggestions are correctly
+                        // aligned on the screen.
+                        acc += len as isize - (cur_hi.col.0 - cur_lo.col.0) as isize;
+                    }
+                    prev_hi = cur_hi;
                     prev_line = sf.get_line(prev_hi.line - 1);
+                    for line in part.snippet.split('\n').skip(1) {
+                        acc = 0;
+                        highlights.push(std::mem::take(&mut line_highlight));
+                        let end: usize = line
+                            .chars()
+                            .map(|c| match c {
+                                '\t' => 4,
+                                _ => 1,
+                            })
+                            .sum();
+                        line_highlight.push(SubstitutionHighlight { start: 0, end });
+                    }
                 }
                 highlights.push(std::mem::take(&mut line_highlight));
                 let only_capitalization = is_case_difference(sm, &buf, bounding_span);

compiler/rustc_hir/src/hir.rs

@@ -974,7 +974,7 @@ pub enum PatKind<'hir> {
     /// Invariant: `pats.len() >= 2`.
     Or(&'hir [Pat<'hir>]),
 
-    /// A path pattern for an unit struct/variant or a (maybe-associated) constant.
+    /// A path pattern for a unit struct/variant or a (maybe-associated) constant.
     Path(QPath<'hir>),
 
     /// A tuple pattern (e.g., `(a, b)`).
@@ -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

@@ -307,7 +307,7 @@ where
     /// relations between `'0` and `'a`).
     ///
     /// The variable `pair` can be either a `(vid, ty)` or `(ty, vid)`
-    /// -- in other words, it is always a (unresolved) inference
+    /// -- in other words, it is always an (unresolved) inference
     /// variable `vid` and a type `ty` that are being related, but the
     /// vid may appear either as the "a" type or the "b" type,
     /// depending on where it appears in the tuple. The trait
@@ -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/infer/undo_log.rs

@@ -96,7 +96,7 @@ impl Default for InferCtxtUndoLogs<'_> {
 }
 
 /// The UndoLogs trait defines how we undo a particular kind of action (of type T). We can undo any
-/// action that is convertable into a UndoLog (per the From impls above).
+/// action that is convertable into an UndoLog (per the From impls above).
 impl<'tcx, T> UndoLogs<T> for InferCtxtUndoLogs<'tcx>
 where
     UndoLog<'tcx>: From<T>,

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_lexer/src/lib.rs

@@ -489,7 +489,7 @@ impl Cursor<'_> {
         // Start is already eaten, eat the rest of identifier.
         self.eat_while(is_id_continue);
         // Known prefixes must have been handled earlier. So if
-        // we see a prefix here, it is definitely a unknown prefix.
+        // we see a prefix here, it is definitely an unknown prefix.
         match self.first() {
             '#' | '"' | '\'' => UnknownPrefix,
             _ => Ident,

compiler/rustc_lint/src/nonstandard_style.rs

@@ -118,7 +118,7 @@ fn to_camel_case(s: &str) -> String {
         })
         .fold((String::new(), None), |(acc, prev): (String, Option<String>), next| {
             // separate two components with an underscore if their boundary cannot
-            // be distinguished using a uppercase/lowercase case distinction
+            // be distinguished using an uppercase/lowercase case distinction
             let join = if let Some(prev) = prev {
                 let l = prev.chars().last().unwrap();
                 let f = next.chars().next().unwrap();

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_lint_defs/src/builtin.rs

@@ -3070,16 +3070,19 @@ declare_lint! {
 
 declare_lint! {
     /// The `rust_2021_incompatible_closure_captures` lint detects variables that aren't completely
-    /// captured in Rust 2021 and affect the Drop order of at least one path starting at this variable.
-    /// It can also detect when a variable implements a trait, but one of its field does not and
-    /// the field is captured by a closure and used with the assumption that said field implements
+    /// captured in Rust 2021, such that the `Drop` order of their fields may differ between
+    /// Rust 2018 and 2021.
+    ///
+    /// It can also detect when a variable implements a trait like `Send`, but one of its fields does not,
+    /// and the field is captured by a closure and used with the assumption that said field implements
     /// the same trait as the root variable.
     ///
     /// ### Example of drop reorder
     ///
     /// ```rust,compile_fail
-    /// # #![deny(rust_2021_incompatible_closure_captures)]
+    /// #![deny(rust_2021_incompatible_closure_captures)]
     /// # #![allow(unused)]
+    ///
     /// struct FancyInteger(i32);
     ///
     /// impl Drop for FancyInteger {
@@ -3133,8 +3136,8 @@ declare_lint! {
     /// ### Explanation
     ///
     /// In the above example, only `fptr.0` is captured in Rust 2021.
-    /// The field is of type *mut i32 which doesn't implement Send, making the code invalid as the
-    /// field cannot be sent between thread safely.
+    /// The field is of type `*mut i32`, which doesn't implement `Send`,
+    /// making the code invalid as the field cannot be sent between threads safely.
     pub RUST_2021_INCOMPATIBLE_CLOSURE_CAPTURES,
     Allow,
     "detects closures affected by Rust 2021 changes",
@@ -3254,6 +3257,7 @@ declare_lint! {
     ///
     /// ```rust,compile_fail
     /// #![deny(rust_2021_incompatible_or_patterns)]
+    ///
     /// macro_rules! match_any {
     ///     ( $expr:expr , $( $( $pat:pat )|+ => $expr_arm:expr ),+ ) => {
     ///         match $expr {
@@ -3275,7 +3279,7 @@ declare_lint! {
     ///
     /// ### Explanation
     ///
-    /// In Rust 2021, the pat matcher will match new patterns, which include the | character.
+    /// In Rust 2021, the `pat` matcher will match additional patterns, which include the `|` character.
     pub RUST_2021_INCOMPATIBLE_OR_PATTERNS,
     Allow,
     "detects usage of old versions of or-patterns",
@@ -3371,7 +3375,7 @@ declare_lint! {
 }
 
 declare_lint! {
-    /// The `unsupported_calling_conventions` lint is output whenever there is an use of the
+    /// The `unsupported_calling_conventions` lint is output whenever there is a use of the
     /// `stdcall`, `fastcall`, `thiscall`, `vectorcall` calling conventions (or their unwind
     /// variants) on targets that cannot meaningfully be supported for the requested target.
     ///

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -62,7 +62,7 @@ crate struct CrateMetadata {
     // --- Some data pre-decoded from the metadata blob, usually for performance ---
     /// Properties of the whole crate.
     /// NOTE(eddyb) we pass `'static` to a `'tcx` parameter because this
-    /// lifetime is only used behind `Lazy`, and therefore acts like an
+    /// lifetime is only used behind `Lazy`, and therefore acts like a
     /// universal (`for<'tcx>`), that is paired up with whichever `TyCtxt`
     /// is being used to decode those values.
     root: CrateRoot<'static>,

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`
 ///
@@ -376,27 +376,27 @@ impl<'tcx, Tag: Provenance> Scalar<Tag> {
         self.to_bits(sz)
     }
 
-    /// Converts the scalar to produce an `u8`. Fails if the scalar is a pointer.
+    /// Converts the scalar to produce a `u8`. Fails if the scalar is a pointer.
     pub fn to_u8(self) -> InterpResult<'static, u8> {
         self.to_unsigned_with_bit_width(8).map(|v| u8::try_from(v).unwrap())
     }
 
-    /// Converts the scalar to produce an `u16`. Fails if the scalar is a pointer.
+    /// Converts the scalar to produce a `u16`. Fails if the scalar is a pointer.
     pub fn to_u16(self) -> InterpResult<'static, u16> {
         self.to_unsigned_with_bit_width(16).map(|v| u16::try_from(v).unwrap())
     }
 
-    /// Converts the scalar to produce an `u32`. Fails if the scalar is a pointer.
+    /// Converts the scalar to produce a `u32`. Fails if the scalar is a pointer.
     pub fn to_u32(self) -> InterpResult<'static, u32> {
         self.to_unsigned_with_bit_width(32).map(|v| u32::try_from(v).unwrap())
     }
 
-    /// Converts the scalar to produce an `u64`. Fails if the scalar is a pointer.
+    /// Converts the scalar to produce a `u64`. Fails if the scalar is a pointer.
     pub fn to_u64(self) -> InterpResult<'static, u64> {
         self.to_unsigned_with_bit_width(64).map(|v| u64::try_from(v).unwrap())
     }
 
-    /// Converts the scalar to produce an `u128`. Fails if the scalar is a pointer.
+    /// Converts the scalar to produce a `u128`. Fails if the scalar is a pointer.
     pub fn to_u128(self) -> InterpResult<'static, u128> {
         self.to_unsigned_with_bit_width(128)
     }

compiler/rustc_middle/src/mir/tcx.rs

@@ -265,7 +265,7 @@ impl BorrowKind {
             BorrowKind::Shared => hir::Mutability::Not,
 
             // We have no type corresponding to a unique imm borrow, so
-            // use `&mut`. It gives all the capabilities of an `&uniq`
+            // use `&mut`. It gives all the capabilities of a `&uniq`
             // and hence is a safe "over approximation".
             BorrowKind::Unique => hir::Mutability::Mut,
 

compiler/rustc_middle/src/mir/visit.rs

@@ -1202,7 +1202,7 @@ pub enum NonUseContext {
     StorageDead,
     /// User type annotation assertions for NLL.
     AscribeUserTy,
-    /// The data of an user variable, for debug info.
+    /// The data of a user variable, for debug info.
     VarDebugInfo,
 }
 

compiler/rustc_middle/src/query/mod.rs

@@ -648,7 +648,7 @@ rustc_queries! {
         }
     }
 
-    /// HACK: when evaluated, this reports a "unsafe derive on repr(packed)" error.
+    /// HACK: when evaluated, this reports an "unsafe derive on repr(packed)" error.
     ///
     /// Unsafety checking is executed for each method separately, but we only want
     /// to emit this error once per derive. As there are some impls with multiple
@@ -1733,7 +1733,7 @@ rustc_queries! {
     }
 
     /// Performs an HIR-based well-formed check on the item with the given `HirId`. If
-    /// we get an `Umimplemented` error that matches the provided `Predicate`, return
+    /// we get an `Unimplemented` error that matches the provided `Predicate`, return
     /// the cause of the newly created obligation.
     ///
     /// This is only used by error-reporting code to get a better cause (in particular, a better

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/closure.rs

@@ -434,7 +434,7 @@ impl BorrowKind {
             ImmBorrow => hir::Mutability::Not,
 
             // We have no type corresponding to a unique imm borrow, so
-            // use `&mut`. It gives all the capabilities of an `&uniq`
+            // use `&mut`. It gives all the capabilities of a `&uniq`
             // and hence is a safe "over approximation".
             UniqueImmBorrow => hir::Mutability::Mut,
         }

compiler/rustc_middle/src/ty/codec.rs

@@ -209,7 +209,7 @@ where
 impl<'tcx, D: TyDecoder<'tcx>> Decodable<D> for Ty<'tcx> {
     #[allow(rustc::usage_of_ty_tykind)]
     fn decode(decoder: &mut D) -> Result<Ty<'tcx>, D::Error> {
-        // Handle shorthands first, if we have an usize > 0x80.
+        // Handle shorthands first, if we have a usize > 0x80.
         if decoder.positioned_at_shorthand() {
             let pos = decoder.read_usize()?;
             assert!(pos >= SHORTHAND_OFFSET);
@@ -228,7 +228,7 @@ impl<'tcx, D: TyDecoder<'tcx>> Decodable<D> for Ty<'tcx> {
 impl<'tcx, D: TyDecoder<'tcx>> Decodable<D> for ty::Binder<'tcx, ty::PredicateKind<'tcx>> {
     fn decode(decoder: &mut D) -> Result<ty::Binder<'tcx, ty::PredicateKind<'tcx>>, D::Error> {
         let bound_vars = Decodable::decode(decoder)?;
-        // Handle shorthands first, if we have an usize > 0x80.
+        // Handle shorthands first, if we have a usize > 0x80.
         Ok(ty::Binder::bind_with_vars(
             if decoder.positioned_at_shorthand() {
                 let pos = decoder.read_usize()?;

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

compiler/rustc_middle/src/ty/layout.rs

@@ -2571,14 +2571,14 @@ where
     /// Compute a `FnAbi` suitable for indirect calls, i.e. to `fn` pointers.
     ///
     /// NB: this doesn't handle virtual calls - those should use `FnAbi::of_instance`
-    /// instead, where the instance is a `InstanceDef::Virtual`.
+    /// instead, where the instance is an `InstanceDef::Virtual`.
     fn of_fn_ptr(cx: &C, sig: ty::PolyFnSig<'tcx>, extra_args: &[Ty<'tcx>]) -> Self;
 
     /// Compute a `FnAbi` suitable for declaring/defining an `fn` instance, and for
     /// direct calls to an `fn`.
     ///
     /// NB: that includes virtual calls, which are represented by "direct calls"
-    /// to a `InstanceDef::Virtual` instance (of `<dyn Trait as Trait>::fn`).
+    /// to an `InstanceDef::Virtual` instance (of `<dyn Trait as Trait>::fn`).
     fn of_instance(cx: &C, instance: ty::Instance<'tcx>, extra_args: &[Ty<'tcx>]) -> Self;
 
     fn new_internal(

compiler/rustc_middle/src/ty/mod.rs

@@ -865,7 +865,7 @@ impl<'tcx> Predicate<'tcx> {
 
 /// Represents the bounds declared on a particular set of type
 /// parameters. Should eventually be generalized into a flag list of
-/// where-clauses. You can obtain a `InstantiatedPredicates` list from a
+/// where-clauses. You can obtain an `InstantiatedPredicates` list from a
 /// `GenericPredicates` by using the `instantiate` method. Note that this method
 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
 /// the `GenericPredicates` are expressed in terms of the bound type
@@ -1371,7 +1371,7 @@ bitflags! {
     }
 }
 
-/// Definition of a variant -- a struct's fields or a enum variant.
+/// Definition of a variant -- a struct's fields or an enum variant.
 #[derive(Debug, HashStable)]
 pub struct VariantDef {
     /// `DefId` that identifies the variant itself.

compiler/rustc_middle/src/ty/sty.rs

@@ -239,7 +239,7 @@ static_assert_size!(TyKind<'_>, 32);
 ///   implements `CK<(u32, u32), Output = u32>`, where `CK` is the trait
 ///   specified above.
 /// - U is a type parameter representing the types of its upvars, tupled up
-///   (borrowed, if appropriate; that is, if an U field represents a by-ref upvar,
+///   (borrowed, if appropriate; that is, if a U field represents a by-ref upvar,
 ///    and the up-var has the type `Foo`, then that field of U will be `&Foo`).
 ///
 /// So, for example, given this function:
@@ -1323,7 +1323,7 @@ pub type Region<'tcx> = &'tcx RegionKind;
 /// These are regions that are stored behind a binder and must be substituted
 /// with some concrete region before being used. There are two kind of
 /// bound regions: early-bound, which are bound in an item's `Generics`,
-/// and are substituted by a `InternalSubsts`, and late-bound, which are part of
+/// and are substituted by an `InternalSubsts`, and late-bound, which are part of
 /// higher-ranked types (e.g., `for<'a> fn(&'a ())`), and are substituted by
 /// the likes of `liberate_late_bound_regions`. The distinction exists
 /// because higher-ranked lifetimes aren't supported in all places. See [1][2].
@@ -1471,7 +1471,7 @@ pub type PolyExistentialProjection<'tcx> = Binder<'tcx, ExistentialProjection<'t
 impl<'tcx> ExistentialProjection<'tcx> {
     /// Extracts the underlying existential trait reference from this projection.
     /// For example, if this is a projection of `exists T. <T as Iterator>::Item == X`,
-    /// then this function would return a `exists T. T: Iterator` existential trait
+    /// then this function would return an `exists T. T: Iterator` existential trait
     /// reference.
     pub fn trait_ref(&self, tcx: TyCtxt<'tcx>) -> ty::ExistentialTraitRef<'tcx> {
         let def_id = tcx.associated_item(self.item_def_id).container.id();

compiler/rustc_middle/src/ty/subst.rs

@@ -22,7 +22,7 @@ use std::ops::ControlFlow;
 
 /// An entity in the Rust type system, which can be one of
 /// several kinds (types, lifetimes, and consts).
-/// To reduce memory usage, a `GenericArg` is a interned pointer,
+/// To reduce memory usage, a `GenericArg` is an interned pointer,
 /// with the lowest 2 bits being reserved for a tag to
 /// indicate the type (`Ty`, `Region`, or `Const`) it points to.
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
@@ -204,12 +204,12 @@ impl<'a, 'tcx> InternalSubsts<'tcx> {
         GeneratorSubsts { substs: self }
     }
 
-    /// Creates a `InternalSubsts` that maps each generic parameter to itself.
+    /// Creates an `InternalSubsts` that maps each generic parameter to itself.
     pub fn identity_for_item(tcx: TyCtxt<'tcx>, def_id: DefId) -> SubstsRef<'tcx> {
         Self::for_item(tcx, def_id, |param, _| tcx.mk_param_from_def(param))
     }
 
-    /// Creates a `InternalSubsts` for generic parameter definitions,
+    /// Creates an `InternalSubsts` for generic parameter definitions,
     /// by calling closures to obtain each kind.
     /// The closures get to observe the `InternalSubsts` as they're
     /// being built, which can be used to correctly

compiler/rustc_middle/src/ty/util.rs

@@ -681,7 +681,7 @@ impl<'tcx> ty::TyS<'tcx> {
     }
 
     /// Checks whether values of this type `T` implement the `Freeze`
-    /// trait -- frozen types are those that do not contain a
+    /// trait -- frozen types are those that do not contain an
     /// `UnsafeCell` anywhere. This is a language concept used to
     /// distinguish "true immutability", which is relevant to
     /// optimization as well as the rules around static values. Note

compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs

@@ -825,7 +825,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 // We're going to want to traverse the first borrowed place to see if we can find
                 // field access to a union. If we find that, then we will keep the place of the
                 // union being accessed and the field that was being accessed so we can check the
-                // second borrowed place for the same union and a access to a different field.
+                // second borrowed place for the same union and an access to a different field.
                 for (place_base, elem) in first_borrowed_place.iter_projections().rev() {
                     match elem {
                         ProjectionElem::Field(field, _) if union_ty(place_base).is_some() => {
@@ -838,7 +838,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             })
             .and_then(|(target_base, target_field)| {
                 // With the place of a union and a field access into it, we traverse the second
-                // borrowed place and look for a access to a different field of the same union.
+                // borrowed place and look for an access to a different field of the same union.
                 for (place_base, elem) in second_borrowed_place.iter_projections().rev() {
                     if let ProjectionElem::Field(field, _) = elem {
                         if let Some(union_ty) = union_ty(place_base) {

compiler/rustc_mir/src/borrow_check/diagnostics/explain_borrow.rs

@@ -606,7 +606,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
     /// Checks if a borrowed value was captured by a trait object. We do this by
     /// looking forward in the MIR from the reserve location and checking if we see
-    /// a unsized cast to a trait object on our data.
+    /// an unsized cast to a trait object on our data.
     fn was_captured_by_trait_object(&self, borrow: &BorrowData<'tcx>) -> bool {
         // Start at the reserve location, find the place that we want to see cast to a trait object.
         let location = borrow.reserve_location;
@@ -666,7 +666,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             }
                             _ => {}
                         },
-                        // If we see a unsized cast, then if it is our data we should check
+                        // If we see an unsized cast, then if it is our data we should check
                         // whether it is being cast to a trait object.
                         Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, ty) => {
                             match operand {

compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs

@@ -72,7 +72,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
                 // If the place is immutable then:
                 //
-                // - Either we deref a immutable ref to get to our final place.
+                // - Either we deref an immutable ref to get to our final place.
                 //    - We don't capture derefs of raw ptrs
                 // - Or the final place is immut because the root variable of the capture
                 //   isn't marked mut and we should suggest that to the user.
@@ -601,7 +601,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             let reason = if let PlaceBase::Upvar(upvar_id) = closure_kind_origin.base {
                 let upvar = ty::place_to_string_for_capture(tcx, closure_kind_origin);
                 let root_hir_id = upvar_id.var_path.hir_id;
-                // we have a origin for this closure kind starting at this root variable so it's safe to unwrap here
+                // we have an origin for this closure kind starting at this root variable so it's safe to unwrap here
                 let captured_places = tables.closure_min_captures[id].get(&root_hir_id).unwrap();
 
                 let origin_projection = closure_kind_origin

compiler/rustc_mir/src/borrow_check/diagnostics/region_errors.rs

@@ -423,7 +423,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         diag
     }
 
-    /// Reports a error specifically for when data is escaping a closure.
+    /// Reports an error specifically for when data is escaping a closure.
     ///
     /// ```text
     /// error: borrowed data escapes outside of function
@@ -566,7 +566,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         diag
     }
 
-    /// Adds a suggestion to errors where a `impl Trait` is returned.
+    /// Adds a suggestion to errors where an `impl Trait` is returned.
     ///
     /// ```text
     /// help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as

compiler/rustc_mir/src/borrow_check/mod.rs

@@ -1241,7 +1241,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             }
         }
 
-        // Special case: you can assign a immutable local variable
+        // Special case: you can assign an immutable local variable
         // (e.g., `x = ...`) so long as it has never been initialized
         // before (at this point in the flow).
         if let Some(local) = place_span.0.as_local() {
@@ -1702,7 +1702,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         // initialization state of `a.b` is all we need to inspect to
         // know if `a.b.c` is valid (and from that we infer that the
         // dereference and `.d` access is also valid, since we assume
-        // `a.b.c` is assigned a reference to a initialized and
+        // `a.b.c` is assigned a reference to an initialized and
         // well-formed record structure.)
 
         // Therefore, if we seek out the *closest* prefix for which we
@@ -1889,7 +1889,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 ProjectionElem::Downcast(_/*adt_def*/, _/*variant_idx*/) =>
                 // assigning to (P->variant) is okay if assigning to `P` is okay
                 //
-                // FIXME: is this true even if P is a adt with a dtor?
+                // FIXME: is this true even if P is an adt with a dtor?
                 { }
 
                 // assigning to (*P) requires P to be initialized
@@ -2003,8 +2003,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             }
 
             if let Some((prefix, mpi)) = shortest_uninit_seen {
-                // Check for a reassignment into a uninitialized field of a union (for example,
-                // after a move out). In this case, do not report a error here. There is an
+                // Check for a reassignment into an uninitialized field of a union (for example,
+                // after a move out). In this case, do not report an error here. There is an
                 // exception, if this is the first assignment into the union (that is, there is
                 // no move out from an earlier location) then this is an attempt at initialization
                 // of the union - we should error in that case.

compiler/rustc_mir/src/borrow_check/universal_regions.rs

@@ -169,7 +169,7 @@ struct UniversalRegionIndices<'tcx> {
     /// used because trait matching and type-checking will feed us
     /// region constraints that reference those regions and we need to
     /// be able to map them our internal `RegionVid`. This is
-    /// basically equivalent to a `InternalSubsts`, except that it also
+    /// basically equivalent to an `InternalSubsts`, except that it also
     /// contains an entry for `ReStatic` -- it might be nice to just
     /// use a substs, and then handle `ReStatic` another way.
     indices: FxHashMap<ty::Region<'tcx>, RegionVid>,

compiler/rustc_mir/src/interpret/operand.rs

@@ -295,7 +295,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     /// we can find the data.
     /// Note that for a given layout, this operation will either always fail or always
     /// succeed!  Whether it succeeds depends on whether the layout can be represented
-    /// in a `Immediate`, not on which data is stored there currently.
+    /// in an `Immediate`, not on which data is stored there currently.
     pub(crate) fn try_read_immediate(
         &self,
         src: &OpTy<'tcx, M::PointerTag>,

compiler/rustc_mir/src/interpret/validity.rs

@@ -857,7 +857,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValueVisitor<'mir, 'tcx, M>
                 // types above, in `visit_primitive`.
                 // In run-time mode, we accept pointers in here.  This is actually more
                 // permissive than a per-element check would be, e.g., we accept
-                // an &[u8] that contains a pointer even though bytewise checking would
+                // a &[u8] that contains a pointer even though bytewise checking would
                 // reject it.  However, that's good: We don't inherently want
                 // to reject those pointers, we just do not have the machinery to
                 // talk about parts of a pointer.

compiler/rustc_mir/src/monomorphize/partitioning/default.rs

@@ -455,7 +455,7 @@ fn mono_item_visibility(
         def_id
     } else {
         return if export_generics && is_generic {
-            // If it is a upstream monomorphization and we export generics, we must make
+            // If it is an upstream monomorphization and we export generics, we must make
             // it available to downstream crates.
             *can_be_internalized = false;
             default_visibility(tcx, def_id, true)

compiler/rustc_mir/src/transform/check_consts/ops.rs

@@ -86,7 +86,7 @@ impl NonConstOp for FnCallNonConst {
     }
 }
 
-/// A call to a `#[unstable]` const fn or `#[rustc_const_unstable]` function.
+/// A call to an `#[unstable]` const fn or `#[rustc_const_unstable]` function.
 ///
 /// Contains the name of the feature that would allow the use of this function.
 #[derive(Debug)]

compiler/rustc_mir/src/transform/const_prop.rs

@@ -145,7 +145,7 @@ impl<'tcx> MirPass<'tcx> for ConstProp {
 
         // FIXME(oli-obk, eddyb) Optimize locals (or even local paths) to hold
         // constants, instead of just checking for const-folding succeeding.
-        // That would require an uniform one-def no-mutation analysis
+        // That would require a uniform one-def no-mutation analysis
         // and RPO (or recursing when needing the value of a local).
         let mut optimization_finder = ConstPropagator::new(body, dummy_body, tcx);
         optimization_finder.visit_body(body);

compiler/rustc_mir/src/transform/coverage/counters.rs

@@ -100,7 +100,7 @@ impl CoverageCounters {
         CounterValueReference::from(next)
     }
 
-    /// Expression IDs start from u32::MAX and go down because a Expression can reference
+    /// Expression IDs start from u32::MAX and go down because an Expression can reference
     /// (add or subtract counts) of both Counter regions and Expression regions. The counter
     /// expression operand IDs must be unique across both types.
     fn next_expression(&mut self) -> InjectedExpressionId {

compiler/rustc_mir/src/transform/coverage/mod.rs

@@ -334,7 +334,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
     /// process (via `take_counter()`).
     ///
     /// Any other counter associated with a `BasicCoverageBlock`, or its incoming edge, but not
-    /// associated with a `CoverageSpan`, should only exist if the counter is a `Expression`
+    /// associated with a `CoverageSpan`, should only exist if the counter is an `Expression`
     /// dependency (one of the expression operands). Collect them, and inject the additional
     /// counters into the MIR, without a reportable coverage span.
     fn inject_indirect_counters(

compiler/rustc_mir/src/transform/rustc_peek.rs

@@ -88,11 +88,11 @@ impl<'tcx> MirPass<'tcx> for SanityCheck {
 /// For each such call, determines what the dataflow bit-state is for
 /// the L-value corresponding to `expr`; if the bit-state is a 1, then
 /// that call to `rustc_peek` is ignored by the sanity check. If the
-/// bit-state is a 0, then this pass emits a error message saying
+/// bit-state is a 0, then this pass emits an error message saying
 /// "rustc_peek: bit not set".
 ///
 /// The intention is that one can write unit tests for dataflow by
-/// putting code into an UI test and using `rustc_peek` to
+/// putting code into a UI test and using `rustc_peek` to
 /// make observations about the results of dataflow static analyses.
 ///
 /// (If there are any calls to `rustc_peek` that do not match the

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

@@ -61,7 +61,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     unpack!(this.expr_into_dest(destination, else_blk, &this.thir[else_opt]))
                 } else {
                     // Body of the `if` expression without an `else` clause must return `()`, thus
-                    // we implicitly generate a `else {}` if it is not specified.
+                    // we implicitly generate an `else {}` if it is not specified.
                     let correct_si = this.source_info(expr_span.shrink_to_hi());
                     this.cfg.push_assign_unit(else_blk, correct_si, destination, this.tcx);
                     else_blk
@@ -208,7 +208,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     );
                     this.diverge_from(loop_block);
 
-                    // The “return” value of the loop body must always be an unit. We therefore
+                    // The “return” value of the loop body must always be a unit. We therefore
                     // introduce a unit temporary as the destination for the loop body.
                     let tmp = this.get_unit_temp();
                     // Execute the body, branching back to the test.

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

@@ -1936,7 +1936,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             // }
             // ```
             //
-            // would yield a `arm_block` something like:
+            // would yield an `arm_block` something like:
             //
             // ```
             // StorageLive(_4);        // _4 is `x`

compiler/rustc_mir_build/src/build/mod.rs

@@ -700,7 +700,7 @@ fn construct_const<'a, 'tcx>(
     builder.finish()
 }
 
-/// Construct MIR for a item that has had errors in type checking.
+/// Construct MIR for an item that has had errors in type checking.
 ///
 /// This is required because we may still want to run MIR passes on an item
 /// with type errors, but normal MIR construction can't handle that in general.
@@ -885,7 +885,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let tcx_hir = tcx.hir();
         let hir_typeck_results = self.typeck_results;
 
-        // In analyze_closure() in upvar.rs we gathered a list of upvars used by a
+        // In analyze_closure() in upvar.rs we gathered a list of upvars used by an
         // indexed closure and we stored in a map called closure_min_captures in TypeckResults
         // with the closure's DefId. Here, we run through that vec of UpvarIds for
         // the given closure and use the necessary information to create upvar

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -788,7 +788,7 @@ impl<'tcx> Cx<'tcx> {
                 self.user_substs_applied_to_ty_of_hir_id(hir_id)
             }
 
-            // `Self` is used in expression as a tuple struct constructor or an unit struct constructor
+            // `Self` is used in expression as a tuple struct constructor or a unit struct constructor
             Res::SelfCtor(_) => self.user_substs_applied_to_ty_of_hir_id(hir_id),
 
             _ => bug!("user_substs_applied_to_res: unexpected res {:?} at {:?}", res, hir_id),

compiler/rustc_mir_build/src/thir/pattern/usefulness.rs

@@ -762,7 +762,7 @@ impl<'p, 'tcx> SubPatSet<'p, 'tcx> {
                     for i in 0..*alt_count {
                         let sub_set = subpats.get(&i).unwrap_or(&SubPatSet::Empty);
                         if sub_set.is_empty() {
-                            // Found a unreachable subpattern.
+                            // Found an unreachable subpattern.
                             spans.push(expanded[i].span);
                         } else {
                             fill_spans(sub_set, spans);

compiler/rustc_parse/src/parser/attr_wrapper.rs

@@ -301,7 +301,7 @@ impl<'a> Parser<'a> {
         // If we 'broke' the last token (e.g. breaking a '>>' token to two '>' tokens),
         // then extend the range of captured tokens to include it, since the parser
         // was not actually bumped past it. When the `LazyTokenStream` gets converted
-        // into a `AttrAnnotatedTokenStream`, we will create the proper token.
+        // into an `AttrAnnotatedTokenStream`, we will create the proper token.
         if self.token_cursor.break_last_token {
             assert_eq!(
                 trailing,
@@ -320,7 +320,7 @@ impl<'a> Parser<'a> {
         } else {
             // Grab any replace ranges that occur *inside* the current AST node.
             // We will perform the actual replacement when we convert the `LazyTokenStream`
-            // to a `AttrAnnotatedTokenStream`
+            // to an `AttrAnnotatedTokenStream`
             let start_calls: u32 = cursor_snapshot_next_calls.try_into().unwrap();
             self.capture_state.replace_ranges[replace_ranges_start..replace_ranges_end]
                 .iter()
@@ -486,7 +486,7 @@ fn make_token_stream(
         if let AttrAnnotatedTokenTree::Token(last_token) = last_token {
             let unglued_first = last_token.kind.break_two_token_op().unwrap().0;
 
-            // A 'unglued' token is always two ASCII characters
+            // An 'unglued' token is always two ASCII characters
             let mut first_span = last_token.span.shrink_to_lo();
             first_span = first_span.with_hi(first_span.lo() + rustc_span::BytePos(1));
 

compiler/rustc_parse/src/parser/expr.rs

@@ -1092,7 +1092,7 @@ impl<'a> Parser<'a> {
         // added to the return value after the fact.
         //
         // Therefore, prevent sub-parser from parsing
-        // attributes by giving them a empty "already-parsed" list.
+        // attributes by giving them an empty "already-parsed" list.
         let attrs = AttrVec::new();
 
         // Note: when adding new syntax here, don't forget to adjust `TokenKind::can_begin_expr()`.

compiler/rustc_parse/src/parser/mod.rs

@@ -152,7 +152,7 @@ pub struct Parser<'a> {
 /// attribute, we parse a nested AST node that has `#[cfg]` or `#[cfg_attr]`
 /// In this case, we use a `ReplaceRange` to replace the entire inner AST node
 /// with `FlatToken::AttrTarget`, allowing us to perform eager cfg-expansion
-/// on a `AttrAnnotatedTokenStream`
+/// on an `AttrAnnotatedTokenStream`
 ///
 /// 2. When we parse an inner attribute while collecting tokens. We
 /// remove inner attributes from the token stream entirely, and
@@ -165,7 +165,7 @@ pub type ReplaceRange = (Range<u32>, Vec<(FlatToken, Spacing)>);
 
 /// Controls how we capture tokens. Capturing can be expensive,
 /// so we try to avoid performing capturing in cases where
-/// we will never need a `AttrAnnotatedTokenStream`
+/// we will never need an `AttrAnnotatedTokenStream`
 #[derive(Copy, Clone)]
 pub enum Capturing {
     /// We aren't performing any capturing - this is the default mode.
@@ -1362,10 +1362,10 @@ pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, sess: &Pa
     }
 }
 
-/// A helper struct used when building a `AttrAnnotatedTokenStream` from
+/// A helper struct used when building an `AttrAnnotatedTokenStream` from
 /// a `LazyTokenStream`. Both delimiter and non-delimited tokens
 /// are stored as `FlatToken::Token`. A vector of `FlatToken`s
-/// is then 'parsed' to build up a `AttrAnnotatedTokenStream` with nested
+/// is then 'parsed' to build up an `AttrAnnotatedTokenStream` with nested
 /// `AttrAnnotatedTokenTree::Delimited` tokens
 #[derive(Debug, Clone)]
 pub enum FlatToken {
@@ -1375,10 +1375,10 @@ pub enum FlatToken {
     /// Holds the `AttributesData` for an AST node. The
     /// `AttributesData` is inserted directly into the
     /// constructed `AttrAnnotatedTokenStream` as
-    /// a `AttrAnnotatedTokenTree::Attributes`
+    /// an `AttrAnnotatedTokenTree::Attributes`
     AttrTarget(AttributesData),
     /// A special 'empty' token that is ignored during the conversion
-    /// to a `AttrAnnotatedTokenStream`. This is used to simplify the
+    /// to an `AttrAnnotatedTokenStream`. This is used to simplify the
     /// handling of replace ranges.
     Empty,
 }

compiler/rustc_privacy/src/lib.rs

@@ -575,7 +575,7 @@ impl EmbargoVisitor<'tcx> {
         }
     }
 
-    /// Given the path segments of a `ItemKind::Use`, then we need
+    /// Given the path segments of an `ItemKind::Use`, then we need
     /// to update the visibility of the intermediate use so that it isn't linted
     /// by `unreachable_pub`.
     ///

compiler/rustc_resolve/src/diagnostics.rs

@@ -956,9 +956,61 @@ impl<'a> Resolver<'a> {
         if macro_kind == MacroKind::Derive && (ident.name == sym::Send || ident.name == sym::Sync) {
             let msg = format!("unsafe traits like `{}` should be implemented explicitly", ident);
             err.span_note(ident.span, &msg);
+            return;
         }
         if self.macro_names.contains(&ident.normalize_to_macros_2_0()) {
             err.help("have you added the `#[macro_use]` on the module/import?");
+            return;
+        }
+        for ns in [Namespace::MacroNS, Namespace::TypeNS, Namespace::ValueNS] {
+            if let Ok(binding) = self.early_resolve_ident_in_lexical_scope(
+                ident,
+                ScopeSet::All(ns, false),
+                &parent_scope,
+                false,
+                false,
+                ident.span,
+            ) {
+                let desc = match binding.res() {
+                    Res::Def(DefKind::Macro(MacroKind::Bang), _) => {
+                        "a function-like macro".to_string()
+                    }
+                    Res::Def(DefKind::Macro(MacroKind::Attr), _) | Res::NonMacroAttr(..) => {
+                        format!("an attribute: `#[{}]`", ident)
+                    }
+                    Res::Def(DefKind::Macro(MacroKind::Derive), _) => {
+                        format!("a derive macro: `#[derive({})]`", ident)
+                    }
+                    Res::ToolMod => {
+                        // Don't confuse the user with tool modules.
+                        continue;
+                    }
+                    Res::Def(DefKind::Trait, _) if macro_kind == MacroKind::Derive => {
+                        "only a trait, without a derive macro".to_string()
+                    }
+                    res => format!(
+                        "{} {}, not {} {}",
+                        res.article(),
+                        res.descr(),
+                        macro_kind.article(),
+                        macro_kind.descr_expected(),
+                    ),
+                };
+                if let crate::NameBindingKind::Import { import, .. } = binding.kind {
+                    if !import.span.is_dummy() {
+                        err.span_note(
+                            import.span,
+                            &format!("`{}` is imported here, but it is {}", ident, desc),
+                        );
+                        // Silence the 'unused import' warning we might get,
+                        // since this diagnostic already covers that import.
+                        self.record_use(ident, binding, false);
+                        return;
+                    }
+                }
+                err.note(&format!("`{}` is in scope, but it is {}", ident, desc));
+                return;
+            }
         }
     }
 

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1826,7 +1826,7 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
         err.emit();
     }
 
-    // FIXME(const_generics): This patches over a ICE caused by non-'static lifetimes in const
+    // FIXME(const_generics): This patches over an ICE caused by non-'static lifetimes in const
     // generics. We are disallowing this until we can decide on how we want to handle non-'static
     // lifetimes in const generics. See issue #74052 for discussion.
     crate fn emit_non_static_lt_in_const_generic_error(&self, lifetime_ref: &hir::Lifetime) {

compiler/rustc_resolve/src/lib.rs

@@ -668,7 +668,7 @@ enum NameBindingKind<'a> {
 }
 
 impl<'a> NameBindingKind<'a> {
-    /// Is this a name binding of a import?
+    /// Is this a name binding of an import?
     fn is_import(&self) -> bool {
         matches!(*self, NameBindingKind::Import { .. })
     }
@@ -3065,7 +3065,7 @@ impl<'a> Resolver<'a> {
             self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
         // Only suggest removing an import if both bindings are to the same def, if both spans
         // aren't dummy spans. Further, if both bindings are imports, then the ident must have
-        // been introduced by a item.
+        // been introduced by an item.
         let should_remove_import = duplicate
             && !has_dummy_span
             && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
@@ -3160,7 +3160,7 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    /// This function adds a suggestion to remove a unnecessary binding from an import that is
+    /// This function adds a suggestion to remove an unnecessary binding from an import that is
     /// nested. In the following example, this function will be invoked to remove the `a` binding
     /// in the second use statement:
     ///
@@ -3212,7 +3212,7 @@ impl<'a> Resolver<'a> {
                     Applicability::MaybeIncorrect,
                 );
             } else {
-                // Remove the entire line if we cannot extend the span back, this indicates a
+                // Remove the entire line if we cannot extend the span back, this indicates an
                 // `issue_52891::{self}` case.
                 err.span_suggestion(
                     import.use_span_with_attributes,

compiler/rustc_serialize/src/json.rs

@@ -1202,7 +1202,7 @@ impl Json {
         matches!(*self, Json::I64(_) | Json::U64(_) | Json::F64(_))
     }
 
-    /// Returns `true` if the Json value is a `i64`.
+    /// Returns `true` if the Json value is an `i64`.
     pub fn is_i64(&self) -> bool {
         matches!(*self, Json::I64(_))
     }
@@ -1217,7 +1217,7 @@ impl Json {
         matches!(*self, Json::F64(_))
     }
 
-    /// If the Json value is a number, returns or cast it to a `i64`;
+    /// If the Json value is a number, returns or cast it to an `i64`;
     /// returns `None` otherwise.
     pub fn as_i64(&self) -> Option<i64> {
         match *self {

compiler/rustc_serialize/src/serialize.rs

@@ -644,7 +644,7 @@ impl<D: Decoder, T: Decodable<D> + Copy> Decodable<D> for Cell<T> {
 }
 
 // FIXME: #15036
-// Should use `try_borrow`, returning a
+// Should use `try_borrow`, returning an
 // `encoder.error("attempting to Encode borrowed RefCell")`
 // from `encode` when `try_borrow` returns `None`.
 

compiler/rustc_session/src/options.rs

@@ -1287,7 +1287,7 @@ options! {
     thinlto: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "enable ThinLTO when possible"),
     thir_unsafeck: bool = (false, parse_bool, [TRACKED],
-        "use the work-in-progress THIR unsafety checker. NOTE: this is unsound (default: no)"),
+        "use the THIR unsafety checker (default: no)"),
     /// We default to 1 here since we want to behave like
     /// a sequential compiler for now. This'll likely be adjusted
     /// in the future. Note that -Zthreads=0 is the way to get

compiler/rustc_span/src/source_map.rs

@@ -100,7 +100,7 @@ pub trait FileLoader {
     /// Query the existence of a file.
     fn file_exists(&self, path: &Path) -> bool;
 
-    /// Read the contents of an UTF-8 file into memory.
+    /// Read the contents of a UTF-8 file into memory.
     fn read_file(&self, path: &Path) -> io::Result<String>;
 }
 

compiler/rustc_target/src/asm/mod.rs

@@ -469,7 +469,7 @@ impl InlineAsmRegClass {
         }
     }
 
-    /// Returns a list of supported types for this register class, each with a
+    /// Returns a list of supported types for this register class, each with an
     /// options target feature required to use this type.
     pub fn supported_types(
         self,

compiler/rustc_trait_selection/src/opaque_types.rs

@@ -77,7 +77,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
     ///     ?0: Iterator<Item = ?1>
     ///     ?1: Debug
     ///
-    /// Moreover, it returns a `OpaqueTypeMap` that would map `?0` to
+    /// Moreover, it returns an `OpaqueTypeMap` that would map `?0` to
     /// info about the `impl Iterator<..>` type and `?1` to info about
     /// the `impl Debug` type.
     ///
@@ -886,7 +886,7 @@ impl<'a, 'tcx> Instantiator<'a, 'tcx> {
                     // }
                     // ```
                     //
-                    // Here, the return type of `foo` references a
+                    // Here, the return type of `foo` references an
                     // `Opaque` indeed, but not one whose value is
                     // presently being inferred. You can get into a
                     // similar situation with closure return types

compiler/rustc_trait_selection/src/traits/codegen.rs

@@ -12,7 +12,7 @@ use rustc_errors::ErrorReported;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::{self, TyCtxt};
 
-/// Attempts to resolve an obligation to a `ImplSource`. The result is
+/// Attempts to resolve an obligation to an `ImplSource`. The result is
 /// a shallow `ImplSource` resolution, meaning that we do not
 /// (necessarily) resolve all nested obligations on the impl. Note
 /// that type check should guarantee to us that all nested

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -2009,7 +2009,7 @@ pub enum ArgKind {
     Arg(String, String),
 
     /// An argument of tuple type. For a "found" argument, the span is
-    /// the location in the source of the pattern. For a "expected"
+    /// the location in the source of the pattern. For an "expected"
     /// argument, it will be None. The vector is a list of (name, ty)
     /// strings for the components of the tuple.
     Tuple(Option<Span>, Vec<(String, String)>),

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1365,7 +1365,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         // When a future does not implement a trait because of a captured type in one of the
         // generators somewhere in the call stack, then the result is a chain of obligations.
         //
-        // Given a `async fn` A that calls a `async fn` B which captures a non-send type and that
+        // Given an `async fn` A that calls an `async fn` B which captures a non-send type and that
         // future is passed as an argument to a function C which requires a `Send` type, then the
         // chain looks something like this:
         //

compiler/rustc_trait_selection/src/traits/project.rs

@@ -62,7 +62,7 @@ enum ProjectionTyCandidate<'tcx> {
     /// Bounds specified on an object type
     Object(ty::PolyProjectionPredicate<'tcx>),
 
-    /// From a "impl" (or a "pseudo-impl" returned by select)
+    /// From an "impl" (or a "pseudo-impl" returned by select)
     Select(Selection<'tcx>),
 }
 
@@ -1011,7 +1011,7 @@ fn prune_cache_value_obligations<'a, 'tcx>(
 /// Note that we used to return `Error` here, but that was quite
 /// dubious -- the premise was that an error would *eventually* be
 /// reported, when the obligation was processed. But in general once
-/// you see a `Error` you are supposed to be able to assume that an
+/// you see an `Error` you are supposed to be able to assume that an
 /// error *has been* reported, so that you can take whatever heuristic
 /// paths you want to take. To make things worse, it was possible for
 /// cycles to arise, where you basically had a setup like `<MyType<$0>

compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs

@@ -24,7 +24,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> {
     ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self::QueryResponse>> {
         // FIXME this `unchecked_map` is only necessary because the
         // query is defined as taking a `ParamEnvAnd<Ty>`; it should
-        // take a `ImpliedOutlivesBounds` instead
+        // take an `ImpliedOutlivesBounds` instead
         let canonicalized = canonicalized.unchecked_map(|ParamEnvAnd { param_env, value }| {
             let ImpliedOutlivesBounds { ty } = value;
             param_env.and(ty)

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -257,7 +257,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         ImplSourceBuiltinData { nested: obligations }
     }
 
-    /// This handles the case where a `auto trait Foo` impl is being used.
+    /// This handles the case where an `auto trait Foo` impl is being used.
     /// The idea is that the impl applies to `X : Foo` if the following conditions are met:
     ///
     /// 1. For each constituent type `Y` in `X`, `Y : Foo` holds

compiler/rustc_trait_selection/src/traits/specialize/mod.rs

@@ -149,7 +149,7 @@ pub(super) fn specializes(tcx: TyCtxt<'_>, (impl1_def_id, impl2_def_id): (DefId,
     let penv = tcx.param_env(impl1_def_id);
     let impl1_trait_ref = tcx.impl_trait_ref(impl1_def_id).unwrap();
 
-    // Create a infcx, taking the predicates of impl1 as assumptions:
+    // Create an infcx, taking the predicates of impl1 as assumptions:
     tcx.infer_ctxt().enter(|infcx| {
         // Normalize the trait reference. The WF rules ought to ensure
         // that this always succeeds.

compiler/rustc_traits/src/chalk/db.rs

@@ -718,7 +718,7 @@ impl<'tcx> chalk_ir::UnificationDatabase<RustInterner<'tcx>> for RustIrDatabase<
     }
 }
 
-/// Creates a `InternalSubsts` that maps each generic parameter to a higher-ranked
+/// Creates an `InternalSubsts` that maps each generic parameter to a higher-ranked
 /// var bound at index `0`. For types, we use a `BoundVar` index equal to
 /// the type parameter index. For regions, we use the `BoundRegionKind::BrNamed`
 /// variant (which has a `DefId`).

compiler/rustc_ty_utils/src/ty.rs

@@ -185,7 +185,7 @@ fn impl_constness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::Constness {
 ///     - a type parameter or projection whose Sizedness can't be known
 ///     - a tuple of type parameters or projections, if there are multiple
 ///       such.
-///     - a Error, if a type contained itself. The representability
+///     - an Error, if a type contained itself. The representability
 ///       check should catch this case.
 fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> ty::AdtSizedConstraint<'_> {
     let def = tcx.adt_def(def_id);
@@ -253,7 +253,7 @@ fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
     // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
     // report these errors right here; this doesn't actually feel
     // right to me, because constructing the environment feels like a
-    // kind of a "idempotent" action, but I'm not sure where would be
+    // kind of an "idempotent" action, but I'm not sure where would be
     // a better place. In practice, we construct environments for
     // every fn once during type checking, and we'll abort if there
     // are any errors at that point, so after type checking you can be

compiler/rustc_typeck/src/astconv/mod.rs

@@ -2350,7 +2350,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             }
             hir::TyKind::Infer => {
                 // Infer also appears as the type of arguments or return
-                // values in a ExprKind::Closure, or as
+                // values in an ExprKind::Closure, or as
                 // the type of local variables. Both of these cases are
                 // handled specially and will not descend into this routine.
                 self.ty_infer(None, ast_ty.span)

compiler/rustc_typeck/src/check/closure.rs

@@ -617,7 +617,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Invoked when we are translating the generator that results
     /// from desugaring an `async fn`. Returns the "sugared" return
     /// type of the `async fn` -- that is, the return type that the
-    /// user specified. The "desugared" return type is a `impl
+    /// user specified. The "desugared" return type is an `impl
     /// Future<Output = T>`, so we do this by searching through the
     /// obligations to extract the `T`.
     fn deduce_future_output_from_obligations(&self, expr_def_id: DefId) -> Option<Ty<'tcx>> {

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -743,7 +743,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // possibly be referring to the current closure,
                     // because we haven't produced the `Closure` for
                     // this closure yet; this is exactly why the other
-                    // code is looking for a self type of a unresolved
+                    // code is looking for a self type of an unresolved
                     // inference variable.
                     ty::PredicateKind::ClosureKind(..) => None,
                     ty::PredicateKind::TypeWellFormedFromEnv(..) => None,

compiler/rustc_typeck/src/check/fn_ctxt/mod.rs

@@ -96,7 +96,7 @@ pub struct FnCtxt<'a, 'tcx> {
     ///   `foo(return)`; we warn on the `foo()` expression. (We then
     ///   update the flag to `WarnedAlways` to suppress duplicate
     ///   reports.) Similarly, if we traverse to a fresh statement (or
-    ///   tail expression) from a `Always` setting, we will issue a
+    ///   tail expression) from an `Always` setting, we will issue a
     ///   warning. This corresponds to something like `{return;
     ///   foo();}` or `{return; 22}`, where we would warn on the
     ///   `foo()` or `22`.

compiler/rustc_typeck/src/check/upvar.rs

@@ -1456,7 +1456,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // an immut-ref after on top of this.
                 ty::Ref(.., hir::Mutability::Mut) => is_mutbl = hir::Mutability::Mut,
 
-                // The place isn't mutable once we dereference a immutable reference.
+                // The place isn't mutable once we dereference an immutable reference.
                 ty::Ref(.., hir::Mutability::Not) => return hir::Mutability::Not,
 
                 // Dereferencing a box doesn't change mutability

compiler/rustc_typeck/src/check_unused.rs

@@ -155,7 +155,7 @@ fn unused_crates_lint(tcx: TyCtxt<'_>) {
         }
 
         // If the extern crate isn't in the extern prelude,
-        // there is no way it can be written as an `use`.
+        // there is no way it can be written as a `use`.
         let orig_name = extern_crate.orig_name.unwrap_or(item.ident.name);
         if !extern_prelude.get(&orig_name).map_or(false, |from_item| !from_item) {
             continue;

compiler/rustc_typeck/src/expr_use_visitor.rs

@@ -819,7 +819,7 @@ fn copy_or_move<'a, 'tcx>(
 }
 
 // - If a place is used in a `ByValue` context then move it if it's not a `Copy` type.
-// - If the place that is a `Copy` type consider it a `ImmBorrow`.
+// - If the place that is a `Copy` type consider it an `ImmBorrow`.
 fn delegate_consume<'a, 'tcx>(
     mc: &mc::MemCategorizationContext<'a, 'tcx>,
     delegate: &mut (dyn Delegate<'tcx> + 'a),

compiler/rustc_typeck/src/outlives/implicit_infer.rs

@@ -297,7 +297,7 @@ pub fn check_explicit_predicates<'tcx>(
         // to apply the substs, and not filter this predicate, we might then falsely
         // conclude that e.g., `X: 'x` was a reasonable inferred requirement.
         //
-        // Another similar case is where we have a inferred
+        // Another similar case is where we have an inferred
         // requirement like `<Self as Trait>::Foo: 'b`. We presently
         // ignore such requirements as well (cc #54467)-- though
         // conceivably it might be better if we could extract the `Foo

library/alloc/src/alloc.rs

@@ -387,7 +387,7 @@ pub mod __alloc_error_handler {
         panic!("memory allocation of {} bytes failed", size)
     }
 
-    // if there is a `#[alloc_error_handler]`
+    // if there is an `#[alloc_error_handler]`
     #[rustc_std_internal_symbol]
     pub unsafe extern "C" fn __rg_oom(size: usize, align: usize) -> ! {
         let layout = unsafe { Layout::from_size_align_unchecked(size, align) };

library/alloc/src/collections/binary_heap.rs

@@ -46,7 +46,7 @@
 //!     }
 //! }
 //!
-//! // Each node is represented as an `usize`, for a shorter implementation.
+//! // Each node is represented as a `usize`, for a shorter implementation.
 //! struct Edge {
 //!     node: usize,
 //!     cost: usize,

library/core/src/array/iter.rs

@@ -45,7 +45,7 @@ impl<T, const N: usize> IntoIter<T, N> {
     /// use std::array;
     ///
     /// for value in array::IntoIter::new([1, 2, 3, 4, 5]) {
-    ///     // The type of `value` is a `i32` here, instead of `&i32`
+    ///     // The type of `value` is an `i32` here, instead of `&i32`
     ///     let _: i32 = value;
     /// }
     /// ```

library/core/src/char/methods.rs

@@ -958,7 +958,7 @@ impl char {
     /// Returns an iterator that yields the uppercase mapping of this `char` as one or more
     /// `char`s.
     ///
-    /// If this `char` does not have a uppercase mapping, the iterator yields the same `char`.
+    /// If this `char` does not have an uppercase mapping, the iterator yields the same `char`.
     ///
     /// If this `char` has a one-to-one uppercase mapping given by the [Unicode Character
     /// Database][ucd] [`UnicodeData.txt`], the iterator yields that `char`.

library/core/src/intrinsics.rs

@@ -1013,7 +1013,7 @@ extern "rust-intrinsic" {
     /// let val_casts = unsafe { &mut *(ptr as *mut i32 as *mut u32) };
     /// ```
     ///
-    /// Turning an `&str` into an `&[u8]`:
+    /// Turning an `&str` into a `&[u8]`:
     ///
     /// ```
     /// // this is not a good way to do this.

library/core/src/iter/adapters/zip.rs

@@ -563,7 +563,7 @@ where
 }
 
 unsafe trait SpecTrustedRandomAccess: Iterator {
-    /// If `Self: TrustedRandomAccess`, it must be safe to call a
+    /// If `Self: TrustedRandomAccess`, it must be safe to call
     /// `Iterator::__iterator_get_unchecked(self, index)`.
     unsafe fn try_get_unchecked(&mut self, index: usize) -> Self::Item;
 }

library/core/src/iter/traits/marker.rs

@@ -25,7 +25,7 @@ impl<I: FusedIterator + ?Sized> FusedIterator for &mut I {}
 /// (lower bound is equal to upper bound), or the upper bound is [`None`].
 /// The upper bound must only be [`None`] if the actual iterator length is
 /// larger than [`usize::MAX`]. In that case, the lower bound must be
-/// [`usize::MAX`], resulting in a [`Iterator::size_hint()`] of
+/// [`usize::MAX`], resulting in an [`Iterator::size_hint()`] of
 /// `(usize::MAX, None)`.
 ///
 /// The iterator must produce exactly the number of elements it reported

library/core/src/mem/mod.rs

@@ -660,7 +660,7 @@ pub unsafe fn zeroed<T>() -> T {
 #[rustc_diagnostic_item = "mem_uninitialized"]
 #[track_caller]
 pub unsafe fn uninitialized<T>() -> T {
-    // SAFETY: the caller must guarantee that an unitialized value is valid for `T`.
+    // SAFETY: the caller must guarantee that an uninitialized value is valid for `T`.
     unsafe {
         intrinsics::assert_uninit_valid::<T>();
         MaybeUninit::uninit().assume_init()