Macro in macro?

I am wondering why does not that work?

identity!( dbg!( "a" ); );

Is there a way to make it working.

PS: I am aware about callback technique.

Playground

macro_rules! identity
{
  (
-   ( $Src : tt )*
+   $( $Src : tt )*
  )
  =>
  {
-   ( $Src )*
+   $( $Src )*
  };
}
3 Likes

Oops! So stupid typo.. Thank you Steffahn!