I can't tell if you are sarcastic, but in case you are not:

By Rice's theorem you cannot be sound and complete, i.e. accept all valid programs and reject all invalid ones. Most languages choose to be sound but not complete, i.e. reject all invalid programs but also some valid ones (C and C++ are the notable exception, although most languages have escape hatches). GP was saying that the fix might reject valid programs that compile today. This is true for some existing soundness bugs, but not necessarily for this one specifically.