rust/tests/mir-opt/copy-prop/cycle.rs

// skip-filecheck
// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
//! Tests that cyclic assignments don't hang CopyProp, and result in reasonable code.
//@ test-mir-pass: CopyProp
fn val() -> i32 {
    1
}

// EMIT_MIR cycle.main.CopyProp.diff
fn main() {
    let mut x = val();
    let y = x;
    let z = y;
    x = z;

    drop(x);
}