diff --git a/ui/single/extern-interrupt-used.rs b/ui/single/extern-interrupt-used.rs
index 2ba316824c..240e7363c7 100644
--- a/ui/single/extern-interrupt-used.rs
+++ b/ui/single/extern-interrupt-used.rs
@@ -4,8 +4,4 @@
 mod app {
     #[task(binds = UART0)]
     fn a(_: a::Context) {}
-
-    extern "C" {
-        fn UART0();
-    }
 }