Macro newtype_index

macro_rules! newtype_index {
    ($(#[$attrs:meta])* $v:vis struct $name:ident { .. }) => { ... };
    ($(#[$attrs:meta])* $v:vis struct $name:ident { $($tokens:tt)+ }) => { ... };
    (@derives      [$($derives:ident,)*]
     @attrs        [$(#[$attrs:meta])*]
     @type         [$type:ident]
     @max          [$max:expr]
     @vis          [$v:vis]
     @debug_format [$debug_format:tt]) => { ... };
    (@handle_debug
     @derives      [$($_derives:ident,)*]
     @type         [$type:ident]
     @debug_format [custom]) => { ... };
    (@handle_debug
     @derives      []
     @type         [$type:ident]
     @debug_format [$debug_format:tt]) => { ... };
    (@handle_debug
     @derives      [$_derive:ident, $($derives:ident,)*]
     @type         [$type:ident]
     @debug_format [$debug_format:tt]) => { ... };
    (@attrs        [$(#[$attrs:meta])*]
     @type         [$type:ident]
     @max          [$max:expr]
     @vis          [$v:vis]
     @debug_format [$debug_format:tt]
                   $($tokens:tt)*) => { ... };
}