Comparing CArray and CString is accepted as valid code but leads to random results

[PtrMan]

The compiler accepts comparison between a char CArray and a CString but it is not compiled/executed as a string comparison correctly! (results here are random).

struct Instr {
    var mnem: CArray[Char, 8]; // mnemonic of op
    var valF: Float32;
}

// interpret instruction
function interp(instr: Instr, stack: Ptr[Stack]) {
    if (instr.mnem) == "PUSHCF  " {
        stack.arr[stack.idx++] = instr.valF; // push
        printf("PUSH\n");
    }
    else if instr.mnem == "LININTER" {
        var intr = stack.arr[stack.idx--];
        var b = stack.arr[stack.idx--];
        var a = stack.arr[stack.idx--];

        stack.arr[stack.idx++] = a*(1.0-intr) + (b-a)*intr;
        printf("LININTER\n");
    }
}