Fix tidy issues, allow no tracking issue for Cilk

src/tools/tidy/src/features.rs

@@ -412,7 +412,10 @@ fn collect_lang_features_in(features: &mut Features, base: &Path, file: &str, ba
 
  let issue_str = parts.next().unwrap().trim();
  let tracking_issue = if issue_str.starts_with("None") {
- if level == Status::Unstable && !next_feature_omits_tracking_issue {
+ // NOTE(jhilton): we allow Cilk to not have a tracking issue since although it's an
+ // unstable feature, progress on it isn't in the main Rust repo so there isn't a
+ // reasonable tracking issue to point to.
+ if level == Status::Unstable && !next_feature_omits_tracking_issue && name != "cilk" {
  tidy_error!(
  bad,
  "{}:{}: no tracking issue for feature {}",

tests/ui/cilk/error_when_value_returned_from_spawned_block.rs

@@ -3,9 +3,9 @@
 // a sync runs.
 
 fn main() {
- let x = {
+ let x = {
  let y = cilk_spawn { 1 };
  y
 //~^ ERROR: used binding `y` is possibly-uninitialized [E0381]
  };
-}
+}

tests/ui/cilk/fib_block_recurse_type_ascription.rs

@@ -12,4 +12,4 @@ fn fib(n: usize) -> usize {
  x + y
 }
 
-fn main() {}
+fn main() {}

tests/ui/feature-gates/feature-gate-cilk.rs

@@ -1,4 +1,4 @@
 fn main() {
  cilk_spawn { 5 }; //~ ERROR cilk keywords are experimental [E0658]
  cilk_sync; //~ ERROR cilk keywords are experimental [E0658]
-}
+}