error[E0599]: no method named `deku_id` found for enum `Body` in the current scope
  --> tests/test_compile/cases/no_deku_id_generic_enum.rs:12:7
   |
5  | pub enum Body<T: for<'a> DekuReader<'a>> {
   | ---------------------------------------- method `deku_id` not found for this enum
...
12 |     n.deku_id();
   |       ^^^^^^^ method not found in `Body<u8>`
   |
   = help: items from traits can only be used if the trait is implemented and in scope
   = note: the following trait defines an item `deku_id`, perhaps you need to implement it:
           candidate #1: `deku::DekuEnumExt`