On Tue, May 23, 2017 at 9:25 PM, Rasmus Schultz <ras...@mindplay.dk> wrote:
> This parameter type widening RFC, I didn't know about, but I have a remark. > > The feature, as implemented, will allow accidental omission of type-hints, > will it not? > > Previously, the implements keyword guaranteed a correctly type-hinted > implementation - it's now possible to (purposefully, obviously, in certain > rare cases) omit type-hints by accident, making the implements keyword much > less (or not any) of a guarantee that the interface is implemented > correctly. > > The addition of an explicit "mixed" or "any" pseudo-type would have made > this possible, without losing the guarantee that the implements keyword > used to provide - that is, it would have been possible to have this feature > for the few cases where it's useful, without affecting safety in the > majority of other cases where it's not. > > I feel like this feature takes a pretty dangerous shortcut by simply > removing a constraint check that we used to have - in favor of supporting a > few rare cases, we removed a guarantee that interfaces and the > implements-keyword has always provided. > > Those rare cases could have been supported in a safe manner by introducing > a "mixed" or "any" type, which would have made the use of this feature > explicit - which would have removed the risk of accidental omission of > type-hints in the majority of cases. > One of the primary motivations behind this RFC is to allow the addition of typehints (for example in library code) without introducing a backwards compatibility break for any code implementing or extending your interface/class. Requiring an explicit "mixed" or "any" type would not allow this. I think this is 95% of the reason for this RFC, so without it, the change itself is probably not worthwhile. > The RFC page doesn't link to any discussion, and the Github thread was shut > down after some negative remarks. > I didn't see a discussion or a vote here on internals - did I miss > something? Where or how did this get discussed and passed? Are these > discussions happening somewhere else besides internals now? > The RFC was discussed in http://markmail.org/message/2oydyyl45v4korau. You participated in that discussion. The vote started in http://markmail.org/message/jgn4hwcgeezzk22w. Both of those were found by searching for the literal RFC name. Nikita
