Re: [RFC] Allow object keys in arrays

Hey Ilija, On Tue, Jan 12, 2021, 17:35 Ilija Tovilo <tovilo.ilija@gmail.com> wrote: > > Definitely disagree here. Your existing code will continue to work fine > without changes. > Code written to deal with array in a generic way will no longer work when invoked through code paths that produce object keys: this is a general problem with widening types overall, and is a clear BC break. This can be verified by expanding the array-key meta-type in tools like vimeo/psalm to include object, then scanning for issues in existing libraries. For example, on generic arrays it was safe to cast keys to string, but that guarantee no longer holds true, and depends on caller-side values, which will change with the new addition. So yes, there needs to be a code migration/adaptation in a large number of downstream infrastructural libraries. Again: this is a common problem with widening types (function return types, operator/constructs possible return types), and hence why I bring it up. Whether the problem can be mitigated is what should be discussed, but the problem is objectively there. >