It is impossible to read a filed of uninitialized struct, but for some reason the write is allowed (but you can't read it back later): ``` Rust struct S {x: i32, y: i32} fn main() { let mut s: S; s.x = 32; // why I don't get an error here, s.y = 12; println!("{}", s.x) // but get it here instead? } ``` Originally reported at https://users.rust-lang.org/t/use-of-possibly-uninitialized-variable-on-an-initialized-variable/4799/4