f - roll our own Duration::saturating_add

Author: jkczyz

lightning-invoice/src/lib.rs

@@ -1208,7 +1208,9 @@ impl Invoice {
 	/// Returns whether the expiry time would pass at the given point in time.
 	/// `at_time` is the timestamp as a duration since the UNIX epoch.
 	pub fn would_expire(&self, at_time: Duration) -> bool {
-		self.duration_since_epoch().saturating_add(self.expiry_time()) < at_time
+		self.duration_since_epoch()
+			.checked_add(self.expiry_time())
+			.unwrap_or_else(|| Duration::new(u64::max_value(), 1_000_000_000 - 1)) < at_time
 	}
 
 	/// Returns the invoice's `min_final_cltv_expiry` time, if present, otherwise