Address Pr comments regarding docstrings

Author: null-sleep

compiler/rustc_typeck/src/expr_use_visitor.rs

@@ -27,11 +27,12 @@ use rustc_span::Span;
 /// employing the ExprUseVisitor.
 pub trait Delegate<'tcx> {
  // The value found at `place` is either copied or moved, depending
- // on mode. Where `diag_expr_id` is the id used for diagnostics for `place`.
+ // on `mode`. Where `diag_expr_id` is the id used for diagnostics for `place`.
  //
- // The reson for a separate expr_id for diagonostics is to support cases
- // like `let pat = upvar`, in such scenarios reporting the pattern (lhs)
- // looks confusing. Instead we prefer to report the discriminant (rhs)
+ // The parameter `diag_expr_id` indicates the HIR id that ought to be used for
+ // diagnostics. Around pattern matching such as `let pat = expr`, the diagnostic
+ // id will be the id of the expression `expr` but the place itself will have
+ // the id of the binding in the pattern `pat`.
  fn consume(
  &mut self,
  place_with_id: &PlaceWithHirId<'tcx>,
@@ -40,11 +41,7 @@ pub trait Delegate<'tcx> {
  );
 
  // The value found at `place` is being borrowed with kind `bk`.
- // `diag_expr_id` is the id used for diagnostics for `place`.
- //
- // The reson for a separate expr_id for diagonostics is to support cases
- // like `let pat = upvar`, in such scenarios reporting the pattern (lhs)
- // looks confusing. Instead we prefer to report the discriminant (rhs)
+ // `diag_expr_id` is the id used for diagnostics (see `consume` for more details).
  fn borrow(
  &mut self,
  place_with_id: &PlaceWithHirId<'tcx>,
@@ -53,11 +50,7 @@ pub trait Delegate<'tcx> {
  );
 
  // The path at `assignee_place` is being assigned to.
- // `diag_expr_id` is the id used for diagnostics for `place`.
- //
- // The reson for a separate expr_id for diagonostics is to support cases
- // like `let pat = upvar`, in such scenarios reporting the pattern (lhs)
- // looks confusing. Instead we prefer to report the discriminant (rhs)
+ // `diag_expr_id` is the id used for diagnostics (see `consume` for more details).
  fn mutate(&mut self, assignee_place: &PlaceWithHirId<'tcx>, diag_expr_id: hir::HirId);
 }