Fix E0732: #[derive] on Enum with No Variants

Wed, 20 May 2026 17:32:04 +0800

1. Symptoms

When attempting to compile Rust code that uses the #[derive] attribute on an enum with zero variants, the compiler produces the E0732 error:

error[E0732]: #[derive] can't be used with enum that has no data
  --> src/main.rs:3:1
   |
3  | #[derive(Debug, Clone)]
   | ^^^^^^^^^^^^^^^^^^^^^^
4  | enum Void {}
   | ---------- has no variants

The error manifests with any trait in the derive macro, whether it’s Debug, Clone, Default, PartialEq, or any other derive-able trait. The compiler will also highlight the enum definition itself as having no variants.

Zero-Variant-Enum on ErrorVault — Developer Error Code Dictionary

Fix E0732: #[derive] on Enum with No Variants

1. Symptoms