transpile: Compound assignment with unsigned RHS sometimes casts twice

[Rua]

C code:

enum E { A };

void test(void) {
    int i = 0;
    unsigned int u = 0;
    enum E e = A;
    e += u;
    i += u;
}

Transpiled result:

pub type E = ::core::ffi::c_uint;
pub const A: E = 0;
#[no_mangle]
pub unsafe extern "C" fn test() {
    unsafe {
        let mut i: ::core::ffi::c_int = 0 as ::core::ffi::c_int;
        let mut u: ::core::ffi::c_uint = 0 as ::core::ffi::c_uint;
        let mut e: E = A;
        e = (e as ::core::ffi::c_uint).wrapping_add(u) as E as E;
        i = (i as ::core::ffi::c_uint).wrapping_add(u) as ::core::ffi::c_int
            as ::core::ffi::c_int;
    }
}

The cast to E and c_int is added twice. This seems to occur if both conditions are met:

• The RHS is unsigned.
• The addition triggers automatic promotion of the LHS to the RHS type, requiring a cast back afterwards.