Error code E0076

The type of the field in a tuple struct isn’t an array when using the #[simd] attribute.

Erroneous code example:

#![allow(unused)]
#![feature(repr_simd)]

fn main() {
#[repr(simd)]
struct Bad(u16); // error!
}

When using the #[simd] attribute to automatically use SIMD operations in tuple structs, if you want a single-lane vector then the field must be a 1-element array, or the compiler will trigger this error.

Fixed example:

#![allow(unused)]
#![feature(repr_simd)]

fn main() {
#[repr(simd)]
struct Good([u16; 1]); // ok!
}