error: #[musli(default)] variant must be empty
 --> tests/ui/illegal_fallback_variant_error.rs:6:13
  |
6 |     #[musli(default)]
  |             ^^^^^^^

error: #[musli(default)] only one fallback variant is supported
  --> tests/ui/illegal_fallback_variant_error.rs:17:13
   |
17 |     #[musli(default)]
   |             ^^^^^^^