remove unused parameters

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -3020,7 +3020,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// assignment to `x.f`).
     pub(crate) fn report_illegal_reassignment(
         &mut self,
-        _location: Location,
         (place, span): (Place<'tcx>, Span),
         assigned_span: Span,
         err_place: Place<'tcx>,
@@ -3072,7 +3071,15 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 format!("mut {name}"),
                 Applicability::MachineApplicable,
             );
-            if !from_arg && decl.has_pattern_match() {
+            if !from_arg
+                && matches!(
+                    decl.local_info(),
+                    LocalInfo::User(BindingForm::Var(VarBindingForm {
+                        opt_match_place: Some((Some(_), _)),
+                        ..
+                    }))
+                )
+            {
                 err.span_suggestion(
                     decl.source_info.span,
                     "to modify the original value, take a borrow instead",

compiler/rustc_borrowck/src/lib.rs

@@ -2174,7 +2174,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 // report the error as an illegal reassignment
                 let init = &self.move_data.inits[init_index];
                 let assigned_span = init.span(self.body);
-                self.report_illegal_reassignment(location, (place, span), assigned_span, place);
+                self.report_illegal_reassignment((place, span), assigned_span, place);
             } else {
                 self.report_mutability_error(place, span, the_place_err, error_access, location)
             }

compiler/rustc_middle/src/mir/mod.rs

@@ -1061,17 +1061,6 @@ impl<'tcx> LocalDecl<'tcx> {
         )
     }
 
-    pub fn has_pattern_match(&self) -> bool {
-        matches!(
-            self.local_info(),
-            LocalInfo::User(BindingForm::Var(VarBindingForm {
-                binding_mode: ty::BindingMode::BindByValue(Mutability::Not),
-                opt_match_place: Some((Some(_), _)),
-                ..
-            }))
-        )
-    }
-
     /// Returns `true` if local is definitely not a `ref ident` or
     /// `ref mut ident` binding. (Such bindings cannot be made into
     /// mutable bindings, but the inverse does not necessarily hold).

tests/ui/pattern/bindings-after-at/pat-at-same-name-both.stderr

@@ -70,13 +70,19 @@ error[E0384]: cannot assign twice to immutable variable `a`
   --> $DIR/pat-at-same-name-both.rs:13:15
    |
 LL |         Ok(a @ b @ a)
-   |                    -
-   |                    |
-   |                    first assignment to `a`
-   |                    help: consider making this binding mutable: `mut a`
+   |                    - first assignment to `a`
 LL |
 LL |         | Err(a @ b @ a)
    |               ^ cannot assign twice to immutable variable
+   |
+help: consider making this binding mutable
+   |
+LL |         Ok(a @ b @ mut a)
+   |                    ~~~~~
+help: to modify the original value, take a borrow instead
+   |
+LL |         Ok(a @ b @ ref mut a)
+   |                    ~~~~~~~~~
 
 error: aborting due to 12 previous errors