Expression attribute duplication

[ghost]

input

Playground

#![feature(stmt_expr_attributes)]

fn main() {
    let foo;
    #[must_use]
    foo = false;
}

output

#![feature(stmt_expr_attributes)]

fn main() {
    let foo;
    #[must_use]
    #[must_use]
    foo = false;
}

[topecongiro]

The problem is that the span of assignment (foo = false) does not include the attribute, so rustfmt incorrectly adds it as 'missing'.