Neaten up a timer.

Author: nnethercote

compiler/rustc_interface/src/queries.rs

@@ -304,7 +304,6 @@ impl Compiler {
     where
         F: for<'tcx> FnOnce(&'tcx Queries<'tcx>) -> T,
     {
-        let mut _timer = None;
         let queries = Queries::new(self);
         let ret = f(&queries);
 
@@ -324,7 +323,7 @@ impl Compiler {
                 .time("serialize_dep_graph", || gcx.enter(rustc_incremental::save_dep_graph));
         }
 
-        _timer = Some(self.session().timer("free_global_ctxt"));
+        let _timer = self.session().timer("free_global_ctxt");
 
         ret
     }