error: `ArrayLength` type can only be used within a struct containing a runtime-sized array marked as `#[size(runtime)]`!
 --> tests/compile_fail/array_length_err.rs:7:8
  |
7 |     a: ArrayLength,
  |        ^^^^^^^^^^^

error: only one field can use the `ArrayLength` type!
 --> tests/compile_fail/array_length_err.rs:8:8
  |
8 |     b: ArrayLength,
  |        ^^^^^^^^^^^