rust/src/librustc_error_codes/error_codes/E0076.md

When using the #[simd] attribute to automatically use SIMD operations in tuple struct, the types in the struct must all be of the same type, or the compiler will trigger this error.

This will cause an error:

#![feature(repr_simd)]

#[repr(simd)]
struct Bad(u16, u32, u32);

This will not:

#![feature(repr_simd)]

#[repr(simd)]
struct Good(u32, u32, u32);