Auto merge of rust-lang#4345 - froydnj:use-noop-more, r=alexcrichton

use Work::noop() more

Using Work::noop() in these places is clearer.

src/cargo/ops/cargo_rustc/custom_build.rs

@@ -79,7 +79,7 @@ pub fn prepare<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>)
                                     unit.pkg, unit.target.name()));
     let overridden = cx.build_state.has_override(unit);
     let (work_dirty, work_fresh) = if overridden {
-        (Work::new(|_| Ok(())), Work::new(|_| Ok(())))
+        (Work::noop(), Work::noop())
     } else {
         build_work(cx, unit)?
     };

src/cargo/ops/cargo_rustc/mod.rs

@@ -234,7 +234,7 @@ fn compile<'a, 'cfg: 'a>(cx: &mut Context<'a, 'cfg>,
         custom_build::prepare(cx, unit)?
     } else if unit.profile.doc && unit.profile.test {
         // we run these targets later, so this is just a noop for now
-        (Work::new(|_| Ok(())), Work::new(|_| Ok(())), Freshness::Fresh)
+        (Work::noop(), Work::noop(), Freshness::Fresh)
     } else {
         let (mut freshness, dirty, fresh) = fingerprint::prepare_target(cx, unit)?;
         let work = if unit.profile.doc {