Re: [RFC] Allow object keys in arrays

On 12.01.21 17:51, Marco Pivetta wrote:

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.

If you look at levels of BC break, this is on the very low end in my opinion. No existing code will break when upgrading to this new PHP version. Only new code written specifically for that PHP version would be impacted, and frameworks/libraries could, if necessary, add additional checks without becoming incompatible with older PHP versions. It helps that currently array keys can be integers or strings, so if the key type is important, some checking is already necessary. Of course tools like Psalm would see a lot of potential issues, but those would only be potential (with new code using this new feature) and having static analyzers reduces the impact of such a BC break even more, as it becomes much easier to spot issues. Might be interesting to change array key type definitions for a few projects/libraries and see if there are that many potential issues, and what they look like.