ICE: unprintable span

[Manishearth]

#[macro_export]
macro_rules! state {
    ( $( $name:ident : $field:ty )* ) => (
        #[derive(Default)]
        struct State {
            $($name : $field),*
        }
    )
}

state! { x: i64 }

pub fn main() {
}

gives:

<anon>:11:11: 6:20 warning: struct field is never used: `x`, #[warn(dead_code)] on by default
(internal compiler error: unprintable span)
<anon>:11:1: 11:18 note: in this expansion of state! (defined in <anon>)

(no backtrace)

[Mark-Simulacrum]

Fixed.

warning: field is never used: `x`, #[warn(dead_code)] on by default
  --> /tmp/t.rs:11:11
   |
11 | state! { x: i64 }
   | ----------^------
   | |
   | in this macro invocation

[Mark-Simulacrum]

E-needstest.

warning: field is never used: `x`
  --> test.rs:11:10
   |
6  | |             $($name : $field),*
   | |____________________________^
...
11 |   state! { x: i64 }
   |  _---------^-------
   | | |
   | | in this macro invocation
   |
   = note: #[warn(dead_code)] on by default