fn main() {
    println!("{:?}", {
        fn foo(a: u32) -> u32 { a } let mut m = std::collections::HashMap::new(); m.insert(0, foo); m[0](42)
    });
}


/* ~~~~=== stderr ===~~~~
   Compiling playground v0.0.1 (file:///playground)
error[E0308]: mismatched types
 --> src/main.rs:5:103
  |
5 |         fn foo(a: u32) -> u32 { a } let mut m = std::collections::HashMap::new(); m.insert(0, foo); m[0](42)
  |                                                                                                       ^
  |                                                                                                       |
  |                                                                                                       expected &{integer}, found integral variable
  |                                                                                                       help: consider borrowing here: `&0`
  |
  = note: expected type `&{integer}`
             found type `{integer}`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.
error: Could not compile `playground`.

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

*/

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

*/