Right; clearly, the difference between the proposed @_implements design and yours will be subtle (but, when it strikes, a totally different function is invoked) and it will be difficult for even advanced Swift users to understand.<br><div class="gmail_quote"><div dir="ltr">On Thu, Apr 13, 2017 at 20:29 Jaden Geller <<a href="mailto:jaden.geller@gmail.com">jaden.geller@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">Oh, I definitely overlooked that part. Thanks for that clarification! I had assumed the compiler changes were only necessary for allowing circular default implementations while still requiring at least one requirement be implemented.<div><br></div><div>That said, it’s possible to implement something very, very similar without compiler changes:</div><div><a href="https://gist.github.com/JadenGeller/7566b3b64b5597ee57e8a509f6fc4bb3#file-context-swift-L43" target="_blank">https://gist.github.com/JadenGeller/7566b3b64b5597ee57e8a509f6fc4bb3#file-context-swift-L43</a></div><div><br></div><div>Cheers,</div><div>Jaden Geller</div></div><div style="word-wrap:break-word"><div><br></div><div><div><blockquote type="cite"><div>On Apr 13, 2017, at 5:58 PM, Xiaodi Wu <<a href="mailto:xiaodi.wu@gmail.com" target="_blank">xiaodi.wu@gmail.com</a>> wrote:</div><br class="m_-9064132398035496944Apple-interchange-newline"><div><div>Jaden, the proposal literally says that a compiler feature named "@_implements" is necessary for the proposed design to work. You can see WIP for that feature in the apple/swift repo.</div><div><br></div><div><br><div class="gmail_quote"><div>On Thu, Apr 13, 2017 at 19:55 Jaden Geller <<a href="mailto:jaden.geller@gmail.com" target="_blank">jaden.geller@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><br><div><blockquote type="cite"><div>On Apr 13, 2017, at 5:18 PM, Xiaodi Wu via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:</div><br class="m_-9064132398035496944m_4552979852900219286Apple-interchange-newline"><div><div style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">Actually, the fact that this behavior cannot even be achieved without currently non-existent compiler features means that it is not possible to understand what's truly going on without reading *this document*, after mastering *both* IEEE floating point *and* Swift generics/protocols/extensions/static vs. dynamic dispatch. All to use `==` correctly. Which is to say, most people will simply not even know if they happen to be using the `==` they did not intend to use.</div><br class="m_-9064132398035496944m_4552979852900219286Apple-interchange-newline"></div></blockquote></div><br></div><div style="word-wrap:break-word"><div>If I understand correctly, I think you’re mistaken. The compiler already selects overloads based on generic context. If `T: FloatingPoint`, then it’ll choose the `==` with signature `<T: FloatingPoint> (T, T) -> Bool`. If `T: Equatable`, then it’ll choose the `==` with signature `<T: Equatable> (T, T) -> Bool`. No new compiler features are necessary for this specific behavior.</div><div><br></div><div>Cheers,</div><div>Jaden Geller</div></div></blockquote></div></div>
</div></blockquote></div><br></div></div></blockquote></div>