Relaxed error pattern, and add test for SystemTime as well.

src/test/run-fail/issue-44216-add-instant.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern:overflow when
+// error-pattern:overflow
 
 use std::time::{Instant, Duration};
 

src/test/run-fail/issue-44216-add-system-time.rs

@@ -0,0 +1,18 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// error-pattern:overflow
+
+use std::time::{Duration, SystemTime};
+
+fn main() {
+    let now = SystemTime::now();
+    let _ = now + Duration::from_secs(u64::max_value());
+}

src/test/run-fail/issue-44216-sub-instant.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern:overflow when
+// error-pattern:overflow
 
 use std::time::{Instant, Duration};
 

src/test/run-fail/issue-44216-sub-system-time.rs

@@ -0,0 +1,18 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// error-pattern:overflow
+
+use std::time::{Duration, SystemTime};
+
+fn main() {
+    let now = SystemTime::now();
+    let _ = now - Duration::from_secs(u64::max_value());
+}