Using an untyped, one-letter variable binding as an argument to a function and then not using it until over 100 lines later is just mean.

src/bootstrap/flags.rs

@@ -89,7 +89,7 @@ pub fn parse(args: &[String]) -> Flags {
         opts.optopt("j", "jobs", "number of jobs to run in parallel", "JOBS");
         opts.optflag("h", "help", "print this help message");
 
-        let usage = |n, opts: &Options| -> ! {
+        let usage = |exit_code, opts: &Options| -> ! {
             let subcommand_help = format!("\
 Usage: x.py <subcommand> [options] [<paths>...]
 
@@ -191,7 +191,7 @@ pub fn parse(args: &[String]) -> Flags {
                 }
             }
 
-            process::exit(n);
+            process::exit(exit_code);
         };
         if args.len() == 0 {
             println!("a subcommand must be passed");