diff --git a/cocoa-foundation/src/foundation.rs b/cocoa-foundation/src/foundation.rs
index e8f5879..b9ca8b0 100644
--- a/cocoa-foundation/src/foundation.rs
+++ b/cocoa-foundation/src/foundation.rs
@@ -229,7 +229,7 @@ pub trait NSProcessInfo: Sized {
         msg_send![class!(NSProcessInfo), processInfo]
     }
 
-    unsafe fn systemUptime(_: Self) -> NSTimeInterval;
+    unsafe fn systemUptime(self) -> NSTimeInterval;
     unsafe fn processName(self) -> id;
     unsafe fn operatingSystemVersion(self) -> NSOperatingSystemVersion;
     unsafe fn isOperatingSystemAtLeastVersion(self, version: NSOperatingSystemVersion) -> bool;