[Bug][Compiler-v2] STLOC_UNSAFE_TO_DESTROY_ERROR

[zzjas]

🐛 Bug

Compiling the following code with V2:

module 0xCAFE::Module0 {
    struct Struct0 has drop, copy {
        x: bool,
    }

    public fun function5(var21: bool, var23: bool) {
        let var67 =  (&(var21) != &((var21 || var23)));
        Struct0 {
            x: var21
        };
    }
}

will raise:

bug: bytecode verification failed with unexpected status code `STLOC_UNSAFE_TO_DESTROY_ERROR`. This is a compiler bug, consider reporting it.
  ┌─ ~/debug_package/sources/repro.move:7:36
  │
7 │         let var67 =  (&(var21) != &((var21 || var23)));
  │                                    ^^^^^^^^^^^^^^^^^^

{
  "Error": "Move compilation failed: exiting with bytecode verification errors"
}

It can be compiled successfully with V1.

Additional context

If we add inline for function5, it will compile fine:

module 0xCAFE::Module0 {
    struct Struct0 has drop, copy {
        x: bool,
    }

    public inline fun function5(var21: bool, var23: bool) {
        let var67 =  (&(var21) != &((var21 || var23)));
        Struct0 {
            x: var21
        };
    }
}

However, if we add a caller like:

public fun caller(a: bool, b: bool) {
       function5(a, b);
}

It will give the same error.

---

If the use of var21 is removed, i.e.:

module 0xCAFE::Module0 {
    public fun function5(var21: bool, var23: bool) {
        let var67 =  (&(var21) != &((var21 || var23)));
    }
}

Compiling it will only raise a known issue:

error: reference safety check failed on bytecode level. This is a known issue, to be fixed later, resulting from differences between safety rules of the v1 and v2 compiler. Try to rewrite your code to workaround this problem.
  ┌─ ~/debug_package/sources/repro.move:3:36
  │
3 │         let var67 =  (&(var21) != &((var21 || var23)));
  │                                    ^^^^^^^^^^^^^^^^^^

{
  "Error": "Move compilation failed: exiting with bytecode verification errors"
}

[wrwg]

Can't reproduce this at head.

[wrwg]

In fact it is reproducible but only if optimizations is off. This might be only the case since peephole opts have landed (@vineethk ). I'll add a test case for further investigation.

[wrwg]

Fixed by #14310