"Inline macro" doesn't work inside proc_macro_attribute

If I have normal function, I could expand macros like println inside it

fn test1() {
  println!("hello"); // I could do "inline macro" here
}

But I couldn't if the function under proc_macro_attribute like async_trait

#[async_trait]
impl A for S {
  fn test2() {
    println!("hello"); // I couldn't do "inline macro" here
  }
}

I know in some cases the outer proc_macro_attribute would change the AST inside it while I think in many cases it just keeps the inner TokenStream

Start by reproducing the two examples in the issue: an inline println! in a normal function and inside an impl using #[async_trait]. Trace how rust-analyzer handles the proc_macro_attribute and its inner TokenStream, then verify that inline macros work in the attributed case without breaking cases where the attribute changes the AST.