Rice’s theorem applies to any non-trivial semantic property.

Looking at the docs, I’m not really sure CodeQL is semantic in the same sense as Rices theorem. It looks syntactic more than semantic.

Eg breaking Rices theorem would require it to detect that an application isn’t vulnerable if it contains the vulnerability but only in paths that are unreachable. Like

    if request.params.limit > 1000:
         throw error
    # 1000 lines of code
    if request.params.limit > 1000:
         call_vulnerable_code()

It’s probably demonstrably true that there is syntactically a path to the vulnerability, I’m a little dubious that it’s demonstrably true the code path is actually reachable without executing the code.

> We’re not talking about decidability of some semantic property in the general case; we’re talking about a specific claim about specific code

Is CodeQL special cased for your code? I very much doubt that. Then it must work in the general case. At that point decidability is impossible and at best either false positives or false negatives can be guaranteed to be absent, but not both (possibly neither of them!)

I don't doubt CodeQL claims can be demonstrably true, that's still coherent with Rice's theorem. However it does mean you'll have false negatives, that is cases where CodeQL reports no provable claim while your code is vulnerable to some issues.