Macro specialize_call::specialize_call

macro_rules! specialize_call {
    (@single_mapping,
        ( $($acc_p:pat),* ),
        ( $($acc_t:ty),* ),
        $func:tt, $args:tt, $select:tt,
        [ ($p:pat => $($t:ty),+ ) $(, $p_t:tt)* $(,)* ],
        $mappings:tt
    ) => { ... };
    (@single_mapping,
        $acc_p:tt, $acc_t: tt,
        $func:tt, $args:tt, $select:tt,
        [],
        $mappings:tt
    ) => { ... };
    (@specialize_call,
        $acc_p:tt,
        $acc_t:tt,
        $func:tt,
        $args:tt,
        $select:tt,

        ($head:tt $(, $tail:tt)*)
    ) => { ... };
    (@specialize_call,
        $acc_p:tt,
        $acc_t:tt,
        $func:tt,
        $args:tt,
        $select:tt,

        ()
    ) => { ... };
    (@maybe_invoke,
        ( $($acc_p:pat),* ),
        ( $($acc_t:ty),* ),
        $select:expr,
        $func:ident,
        ($($arg:expr),*)
    ) => { ... };
    ($func:ident, ($($arg:expr),* $(,)*), $select:expr, $($mapping:tt),+ $(,)*) => { ... };
}