Error code E0074

Note: this error code is no longer emitted by the compiler.

When using the #[simd] attribute on a tuple struct, the components of the tuple struct must all be of a concrete, nongeneric type so the compiler can reason about how to use SIMD with them. This error will occur if the types are generic.

This will cause an error:

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

fn main() {
#[repr(simd)]
struct Bad<T>(T, T, T, T);
}

This will not:

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

fn main() {
#[repr(simd)]
struct Good(u32, u32, u32, u32);
}