Switch to rust 1.37.0

rust-toolchain

@@ -1 +1 @@
-1.36.0
+1.37.0

src/rust/engine/fs/src/lib.rs

@@ -627,7 +627,7 @@ impl PosixFS {
       .read_dir()?
       .map(|readdir| {
         let dir_entry = readdir?;
-        let (file_type, compute_metadata): (_, Box<FnOnce() -> Result<_, _>>) =
+        let (file_type, compute_metadata): (_, Box<dyn FnOnce() -> Result<_, _>>) =
           match self.symlink_behavior {
             SymlinkBehavior::Aware => {
               // Use the dir_entry metadata, which is symlink aware.

src/rust/engine/fs/store/src/snapshot.rs

@@ -407,10 +407,10 @@ impl Snapshot {
               let files: Vec<_> = dir.get_files().iter().map(|file| file.get_name().to_owned()).collect();
 
               match (saw_matching_dir, extra_directories.is_empty() && files.is_empty()) {
-                (false, true) => return futures::future::ok(futures::future::Loop::Break(bazel_protos::remote_execution::Directory::new())).to_boxed(),
+                (false, true) => futures::future::ok(futures::future::Loop::Break(bazel_protos::remote_execution::Directory::new())).to_boxed(),
                 (false, false) => {
                   // Prefer "No subdirectory found" error to "had extra files" error.
-                  return futures::future::err(format!(
+                  futures::future::err(format!(
                     "Cannot strip prefix {} from root directory {:?} - {}directory{} didn't contain a directory named {}{}",
                     already_stripped.join(&prefix).display(),
                     root_digest,
@@ -421,14 +421,14 @@ impl Snapshot {
                   )).to_boxed()
                 },
                 (true, false) => {
-                  return futures::future::err(format!(
+                  futures::future::err(format!(
                     "Cannot strip prefix {} from root directory {:?} - {}directory{} contained non-matching {}",
                     already_stripped.join(&prefix).display(),
                     root_digest,
                     if has_already_stripped_any { "sub" } else { "root " },
                     if has_already_stripped_any { format!(" {}", already_stripped.display()) } else { String::new() },
                     Self::directories_and_files(&extra_directories, &files),
-                  )).to_boxed();
+                  )).to_boxed()
                 },
                 (true, true) => {
                   // Must be 0th index, because we've checked that we saw a matching directory, and no others.

src/rust/engine/process_execution/src/speculate.rs

@@ -155,7 +155,7 @@ mod tests {
     is_err: bool,
     call_counter: Arc<Mutex<u32>>,
   ) -> DelayedCommandRunner {
-    let mut result;
+    let result;
     if is_err {
       result = Err(msg.into());
     } else {

src/rust/engine/serverset/src/lib.rs

@@ -92,7 +92,7 @@ struct Inner<T: Clone> {
   // connection will be used.
   next_connection: usize,
 
-  connect: Box<Fn(&str) -> T + 'static + Send>,
+  connect: Box<dyn Fn(&str) -> T + 'static + Send>,
 
   connection_limit: usize,