remove unused muts

compiler/rustc_ast_pretty/src/pp.rs

@@ -360,7 +360,7 @@ impl Printer {
 
  fn check_stack(&mut self, mut depth: usize) {
  while let Some(&index) = self.scan_stack.back() {
- let mut entry = &mut self.buf[index];
+ let entry = &mut self.buf[index];
  match entry.token {
  Token::Begin(_) => {
  if depth == 0 {

compiler/rustc_borrowck/src/member_constraints.rs

@@ -221,7 +221,7 @@ fn append_list(
 ) {
  let mut p = target_list;
  loop {
- let mut r = &mut constraints[p];
+ let r = &mut constraints[p];
  match r.next_constraint {
  Some(q) => p = q,
  None => {

compiler/rustc_hir_analysis/src/check/region.rs

@@ -421,7 +421,7 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
  let target_scopes = visitor.fixup_scopes.drain(start_point..);
 
  for scope in target_scopes {
- let mut yield_data =
+ let yield_data =
  visitor.scope_tree.yield_in_scope.get_mut(&scope).unwrap().last_mut().unwrap();
  let count = yield_data.expr_and_pat_count;
  let span = yield_data.span;

compiler/rustc_session/src/options.rs

@@ -917,7 +917,7 @@ mod parse {
  }
  }
 
- let mut options = slot.get_or_insert_default();
+ let options = slot.get_or_insert_default();
  let mut seen_always = false;
  let mut seen_never = false;
  let mut seen_ignore_loops = false;

tests/ui/suggestions/suggest-mut-method-for-loop-hashmap.fixed

@@ -11,7 +11,7 @@ fn main() {
  let mut map = HashMap::new();
  map.insert("a", Test { v: 0 });
 
- for (_k, mut v) in map.iter_mut() {
+ for (_k, v) in map.iter_mut() {
  //~^ HELP use mutable method
  //~| NOTE this iterator yields `&` references
  v.v += 1;

tests/ui/suggestions/suggest-mut-method-for-loop-hashmap.rs

@@ -11,7 +11,7 @@ fn main() {
  let mut map = HashMap::new();
  map.insert("a", Test { v: 0 });
 
- for (_k, mut v) in map.iter() {
+ for (_k, v) in map.iter() {
  //~^ HELP use mutable method
  //~| NOTE this iterator yields `&` references
  v.v += 1;

tests/ui/suggestions/suggest-mut-method-for-loop-hashmap.stderr

@@ -1,11 +1,11 @@
 error[E0594]: cannot assign to `v.v`, which is behind a `&` reference
  --> $DIR/suggest-mut-method-for-loop-hashmap.rs:17:9
  |
-LL | for (_k, mut v) in map.iter() {
- |  ----------
- |  | |
- |  | help: use mutable method: `iter_mut()`
- |  this iterator yields `&` references
+LL | for (_k, v) in map.iter() {
+ | ----------
+ | | |
+ | | help: use mutable method: `iter_mut()`
+ | this iterator yields `&` references
 ...
 LL | v.v += 1;
  | ^^^^^^^^ `v` is a `&` reference, so the data it refers to cannot be written