fn main() {
    println!("{:?}", {
        macro_rules! m { ($b:block) => (  {let a = 1; $block} ) } m!({a})
    });
}


/* ~~~~=== stderr ===~~~~
   Compiling playground v0.0.1 (file:///playground)
error: unknown macro variable `block`
 --> src/main.rs:5:55
  |
5 |         macro_rules! m { ($b:block) => (  {let a = 1; $block} ) } m!({a})
  |                                                       ^^^^^^      ------- in this macro invocation
  |                                                       |
  |                                                       unknown macro variable

error: aborting due to previous error

error: Could not compile `playground`.

To learn more, run the command again with --verbose.

*/

/* ~~~~=== stdout ===~~~~

*/