unexpected results from bitwise complement operator `!`

[nobel-sh]

The ! operator produces unexpected results.

fn main(){
   let a: i32 = 5;
   let b = !a; // expected -6 gccrs gives 0.
}

Godbolt: https://godbolt.org/z/cKPPz1bYc

[nobel-sh]

I'm not entirely sure, but it seems that the operator is interpreting the least significant bit of the number as a boolean value and complementing it.