Macro Statements should be also an Expr

[edwin0cheng]

e.g:

macro_rules! identity { ($($es:tt)*) => { $($es)* } }

fn main() -> usize { 
  identity! { let _ = (); }   //  statements
  identity! { let _ = (); 0 }   // expr, return 0
}

[edwin0cheng]

CC rust-lang/rust-analyzer#7845

[edwin0cheng]

(ping) I am not familiar ungrammer part, so I would like to someone to review this PR first :)

[jonas-schievink]

This does seem like a correct change, yeah.

bors r+

[bors]

Build succeeded:

• Rust