These error markers point to nothing, which is less than ideal. The `note` does at least help somewhat. ``` error[E0080]: constant evaluation error --> src/lib.rs:5:30 | 5 | | ^^^^^^^^^^^ unimplemented constant expression: enum variants | note: for repeat count here --> examples/main.rs:4:22 | 4 | let test_x = [0; constenum::CRATE_ONE]; | ^^^^^^^^^^^^^^^^^^^^ ``` ---- **src/lib.rs** ```rust pub enum MyEnum { ONE = 1, } pub const CRATE_ONE: usize = MyEnum::ONE as usize; ``` **examples/main.rs** ```rust extern crate constenum; fn main() { let test_x = [0; constenum::CRATE_ONE]; } ``` Execute via `cargo build --example=main` - `rustc 1.14.0 (e8a012324 2016-12-16)` - [Originally from Stack Overflow](http://stackoverflow.com/q/41501411/155423)