diff --git a/objc2/src/macros/extern_methods.rs b/objc2/src/macros/extern_methods.rs
index 85b387b7a..22073d3e6 100644
--- a/objc2/src/macros/extern_methods.rs
+++ b/objc2/src/macros/extern_methods.rs
@@ -329,7 +329,7 @@ macro_rules! __inner_extern_methods {
             $crate::msg_send;
             $self;
             ($($sel)*);
-            ($($arg),*);
+            ($($arg,)*);
         )
     };
     {
@@ -346,198 +346,53 @@ macro_rules! __inner_extern_methods {
             $crate::msg_send;
             Self::class();
             ($($sel)*);
-            ($($arg),*);
+            ($($arg,)*);
         )
     };
 }
 
 /// Zip selector and arguments, and forward to macro.
-///
-/// TODO: Investigate if there's a better way of doing this.
 #[doc(hidden)]
 #[macro_export]
 macro_rules! __collect_msg_send {
+    // Selector with no arguments
     (
         $macro:path;
         $obj:expr;
-        ($s:ident);
-        ();
-    ) => {{
-        $macro![$obj, $s]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident:);
-        ($a1:expr);
+        ($sel:ident);
+        ($(,)?);
     ) => {{
-        $macro![$obj, $s1: $a1]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident:);
-        ($a1:expr, $a2:expr);
-    ) => {{
-        $macro![$obj, $s1: $a1, $s2: $a2]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident:);
-        ($a1:expr, $a2:expr, $a3:expr);
-    ) => {{
-        $macro![$obj, $s1: $a1, $s2: $a2, $s3: $a3]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr);
-    ) => {{
-        $macro![$obj, $s1: $a1, $s2: $a2, $s3: $a3, $s4: $a4]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident: $s5:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr);
-    ) => {{
-        $macro![$obj, $s1: $a1, $s2: $a2, $s3: $a3, $s4: $a4, $s5: $a5]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident: $s5:ident: $s6:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr);
-    ) => {{
-        $macro![
-            $obj,
-            $s1: $a1,
-            $s2: $a2,
-            $s3: $a3,
-            $s4: $a4,
-            $s5: $a5,
-            $s6: $a6
-        ]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident: $s5:ident: $s6:ident: $s7:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr, $a7:expr);
-    ) => {{
-        $macro![
-            $obj,
-            $s1: $a1,
-            $s2: $a2,
-            $s3: $a3,
-            $s4: $a4,
-            $s5: $a5,
-            $s6: $a6,
-            $s7: $a7
-        ]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident: $s5:ident: $s6:ident: $s7:ident: $s8:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr, $a7:expr, $a8:expr);
-    ) => {{
-        $macro![
-            $obj,
-            $s1: $a1,
-            $s2: $a2,
-            $s3: $a3,
-            $s4: $a4,
-            $s5: $a5,
-            $s6: $a6,
-            $s7: $a7,
-            $s8: $a8
-        ]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident: $s5:ident: $s6:ident: $s7:ident: $s8:ident: $s9:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr, $a7:expr, $a8:expr, $a9:expr);
-    ) => {{
-        $macro![
-            $obj,
-            $s1: $a1,
-            $s2: $a2,
-            $s3: $a3,
-            $s4: $a4,
-            $s5: $a5,
-            $s6: $a6,
-            $s7: $a7,
-            $s8: $a8,
-            $s9: $a9
-        ]
-    }};
-    (
-        $macro:path;
-        $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident: $s5:ident: $s6:ident: $s7:ident: $s8:ident: $s9:ident: $s10:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr, $a7:expr, $a8:expr, $a9:expr, $a10:expr);
-    ) => {{
-        $macro![
-            $obj,
-            $s1: $a1,
-            $s2: $a2,
-            $s3: $a3,
-            $s4: $a4,
-            $s5: $a5,
-            $s6: $a6,
-            $s7: $a7,
-            $s8: $a8,
-            $s9: $a9,
-            $s10: $a10
-        ]
+        $macro![$obj, $sel]
     }};
+
+    // Base case
     (
         $macro:path;
         $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident: $s5:ident: $s6:ident: $s7:ident: $s8:ident: $s9:ident: $s10:ident: $s11:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr, $a7:expr, $a8:expr, $a9:expr, $a10:expr, $a11:expr);
+        ();
+        ($(,)?);
+        $($output:tt)+
     ) => {{
-        $macro![
-            $obj,
-            $s1: $a1,
-            $s2: $a2,
-            $s3: $a3,
-            $s4: $a4,
-            $s5: $a5,
-            $s6: $a6,
-            $s7: $a7,
-            $s8: $a8,
-            $s9: $a9,
-            $s10: $a10,
-            $s11: $a11
-        ]
+        $macro![$obj, $($output)+]
     }};
+    // tt-munch each argument
     (
         $macro:path;
         $obj:expr;
-        ($s1:ident: $s2:ident: $s3:ident: $s4:ident: $s5:ident: $s6:ident: $s7:ident: $s8:ident: $s9:ident: $s10:ident: $s11:ident: $s12:ident:);
-        ($a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr, $a7:expr, $a8:expr, $a9:expr, $a10:expr, $a11:expr, $a12:expr);
+        ($sel:ident : $($sel_rest:tt)*);
+        ($arg:ident , $($args_rest:tt)*);
+        $($output:tt)*
     ) => {{
-        $macro![
-            $obj,
-            $s1: $a1,
-            $s2: $a2,
-            $s3: $a3,
-            $s4: $a4,
-            $s5: $a5,
-            $s6: $a6,
-            $s7: $a7,
-            $s8: $a8,
-            $s9: $a9,
-            $s10: $a10,
-            $s11: $a11,
-            $s12: $a12
-        ]
+        $crate::__collect_msg_send!(
+            $macro;
+            $obj;
+            ($($sel_rest)*);
+            ($($args_rest)*);
+            $($output)* $sel: $arg,
+        )
     }};
+
+    // If couldn't zip selector and arguments, show useful error message
     ($($_any:tt)*) => {{
         compile_error!("Number of arguments in function and selector did not match!")
     }};
diff --git a/test-ui/ui/extern_methods_wrong_arguments.rs b/test-ui/ui/extern_methods_wrong_arguments.rs
new file mode 100644
index 000000000..8eb5f408d
--- /dev/null
+++ b/test-ui/ui/extern_methods_wrong_arguments.rs
@@ -0,0 +1,47 @@
+use objc2::{extern_class, extern_methods, ClassType};
+use objc2::foundation::NSObject;
+
+extern_class!(
+    pub struct MyObject;
+
+    unsafe impl ClassType for MyObject {
+        type Superclass = NSObject;
+    }
+);
+
+extern_methods!(
+    unsafe impl MyObject {
+        #[sel(a:)]
+        fn a();
+    }
+);
+
+extern_methods!(
+    unsafe impl MyObject {
+        #[sel(b)]
+        fn b(arg: i32);
+    }
+);
+
+extern_methods!(
+    unsafe impl MyObject {
+        #[sel(c:d:e:)]
+        fn c(arg1: i32, arg2: u32);
+    }
+);
+
+extern_methods!(
+    unsafe impl MyObject {
+        #[sel(x:)]
+        fn x(&self);
+    }
+);
+
+extern_methods!(
+    unsafe impl MyObject {
+        #[sel(y)]
+        fn y(&self, arg: i32);
+    }
+);
+
+fn main() {}
diff --git a/test-ui/ui/extern_methods_wrong_arguments.stderr b/test-ui/ui/extern_methods_wrong_arguments.stderr
new file mode 100644
index 000000000..678d64852
--- /dev/null
+++ b/test-ui/ui/extern_methods_wrong_arguments.stderr
@@ -0,0 +1,64 @@
+error: Number of arguments in function and selector did not match!
+  --> ui/extern_methods_wrong_arguments.rs
+   |
+   | / extern_methods!(
+   | |     unsafe impl MyObject {
+   | |         #[sel(a:)]
+   | |         fn a();
+   | |     }
+   | | );
+   | |_^
+   |
+   = note: this error originates in the macro `$crate::__collect_msg_send` which comes from the expansion of the macro `extern_methods` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: Number of arguments in function and selector did not match!
+  --> ui/extern_methods_wrong_arguments.rs
+   |
+   | / extern_methods!(
+   | |     unsafe impl MyObject {
+   | |         #[sel(b)]
+   | |         fn b(arg: i32);
+   | |     }
+   | | );
+   | |_^
+   |
+   = note: this error originates in the macro `$crate::__collect_msg_send` which comes from the expansion of the macro `extern_methods` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: Number of arguments in function and selector did not match!
+  --> ui/extern_methods_wrong_arguments.rs
+   |
+   | / extern_methods!(
+   | |     unsafe impl MyObject {
+   | |         #[sel(c:d:e:)]
+   | |         fn c(arg1: i32, arg2: u32);
+   | |     }
+   | | );
+   | |_^
+   |
+   = note: this error originates in the macro `$crate::__collect_msg_send` which comes from the expansion of the macro `extern_methods` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: Number of arguments in function and selector did not match!
+  --> ui/extern_methods_wrong_arguments.rs
+   |
+   | / extern_methods!(
+   | |     unsafe impl MyObject {
+   | |         #[sel(x:)]
+   | |         fn x(&self);
+   | |     }
+   | | );
+   | |_^
+   |
+   = note: this error originates in the macro `$crate::__collect_msg_send` which comes from the expansion of the macro `extern_methods` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: Number of arguments in function and selector did not match!
+  --> ui/extern_methods_wrong_arguments.rs
+   |
+   | / extern_methods!(
+   | |     unsafe impl MyObject {
+   | |         #[sel(y)]
+   | |         fn y(&self, arg: i32);
+   | |     }
+   | | );
+   | |_^
+   |
+   = note: this error originates in the macro `$crate::__collect_msg_send` which comes from the expansion of the macro `extern_methods` (in Nightly builds, run with -Z macro-backtrace for more info)