Macro expand_method

macro_rules! expand_method {
    (self @ $method_name:ident, [$($generics:tt)*], [$($arg_names:ident : $arg_types:ty,)*], $ret:ty, $js_name:literal, $last_variadic:literal) => { ... };
    (constructor @ $method_name:ident, [$($generics:tt)*], [$($arg_names:ident : $arg_types:ty,)*], $ret:ty, $interface_name:literal, $last_variadic:literal) => { ... };
    (free @ $method_name:ident, [$($generics:tt)*], [$($arg_names:ident : $arg_types:ty,)*], $ret:ty, $function_name:literal, $last_variadic:literal) => { ... };
}