Update sys::time impls to have checked_sub_instant

1 files changed, 3 insertions, 5 deletions

diff --git a/src/libstd/sys/cloudabi/time.rs b/src/libstd/sys/cloudabi/time.rs
index d7502c61eff..49a234e1158 100644
--- a/src/libstd/sys/cloudabi/time.rs
+++ b/src/libstd/sys/cloudabi/time.rs
@@ -33,11 +33,9 @@ impl Instant {
         Instant { t: 0 }
     }
 
-    pub fn sub_instant(&self, other: &Instant) -> Duration {
-        let diff = self.t
-            .checked_sub(other.t)
-            .expect("second instant is later than self");
-        Duration::new(diff / NSEC_PER_SEC, (diff % NSEC_PER_SEC) as u32)
+    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+        let diff = self.t.checked_sub(other.t)?;
+        Some(Duration::new(diff / NSEC_PER_SEC, (diff % NSEC_PER_SEC) as u32))
     }
 
     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {