diff --git a/rust/lib.rs b/rust/lib.rs
index d80313d..0880239 100644
--- a/rust/lib.rs
+++ b/rust/lib.rs
@@ -10,7 +10,7 @@ fn say_hello(name: &str) {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn hello(c: *const c_char) -> () {
+extern "C" fn hello(c: *const c_char) {
     say_hello(unsafe { CStr::from_ptr(c) }.to_str().unwrap())
 }
 
@@ -22,7 +22,7 @@ struct T {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn hello_struct(t: &T) -> () {
+extern "C" fn hello_struct(t: &T) {
     say_hello(&format!("{:?}", t))
 }
 
@@ -34,7 +34,7 @@ enum Shape {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn hello_shape(s: &Shape) -> () {
+extern "C" fn hello_shape(s: &Shape) {
     say_hello(&format!("{:?}", s))
 }