Error code E0435

A non-constant value was used in a constant expression.

Erroneous code example:

#![allow(unused)] fn main() { let foo = 42; let a: [u8; foo]; // error: attempt to use a non-constant value in a constant }

'constant' means 'a compile-time value'.

More details can be found in the Variables and Mutability section of the book.

To fix this error, please replace the value with a constant. Example:

#![allow(unused)] fn main() { let a: [u8; 42]; // ok! }

Or:

#![allow(unused)] fn main() { const FOO: usize = 42; let a: [u8; FOO]; // ok! }