<div dir="ltr">On Sat, Jan 7, 2017 at 5:33 PM, Braeden Profile <span dir="ltr">&lt;<a href="mailto:jhaezhyr12@gmail.com" target="_blank">jhaezhyr12@gmail.com</a>&gt;</span> wrote:<br><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div><div class="h5"><div><blockquote type="cite"><div><div dir="ltr" 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"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div style="word-wrap:break-word"><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(79,129,135)"><span style="font-variant-ligatures:no-common-ligatures;color:rgb(146,146,146)"><div style="font-family:Helvetica;font-size:12px"><br></div><div style="font-family:Helvetica;font-size:12px">Of course, I would love being able to use an initializer setup, but there are serious bugs in the implementation.</div><div style="font-family:Helvetica;font-size:12px"><br></div><div style="font-family:Helvetica;font-size:12px"><pre style="font-family:Consolas,&#39;Liberation Mono&#39;,Menlo,Courier,monospace;font-size:0.94em;border-top-left-radius:3px;border-top-right-radius:3px;border-bottom-right-radius:3px;border-bottom-left-radius:3px;background-color:rgb(248,248,248);border:1px solid rgb(204,204,204);white-space:pre-wrap;word-wrap:break-word;padding:5px"><div style="white-space:normal;font-family:Helvetica;font-size:12px"><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,143,1)"><span style="font-variant-ligatures:no-common-ligatures">protocol</span><span style="font-variant-ligatures:no-common-ligatures"> Clonable</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">{</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">init</span><span style="font-variant-ligatures:no-common-ligatures">(other: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(73,134,114)">Self</span><span style="font-variant-ligatures:no-common-ligatures">)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">}</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"></span><br></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,143,1)"><span style="font-variant-ligatures:no-common-ligatures">extension</span><span style="font-variant-ligatures:no-common-ligatures"> </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(95,174,174)">Clonable</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">{</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">func</span><span style="font-variant-ligatures:no-common-ligatures"> clone() -&gt; </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(73,134,114)">Self</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">                </span>{ </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">return</span><span style="font-variant-ligatures:no-common-ligatures"> type(of: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">self</span><span style="font-variant-ligatures:no-common-ligatures">).</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">init</span><span style="font-variant-ligatures:no-common-ligatures">(o<wbr>ther: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">self</span><span style="font-variant-ligatures:no-common-ligatures">) }</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">}</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"></span><br></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"></span><br></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(95,174,174)"><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">class</span><span style="font-variant-ligatures:no-common-ligatures"> Base: </span><span style="font-variant-ligatures:no-common-ligatures">Clonable</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">{</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">var</span><span style="font-variant-ligatures:no-common-ligatures"> x: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(91,38,153)">Int</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><br class="m_-311399833560624468m_-602078394375739685webkit-block-placeholder"></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">init</span><span style="font-variant-ligatures:no-common-ligatures">(x: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(91,38,153)">Int</span><span style="font-variant-ligatures:no-common-ligatures">)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">                </span>{ </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">self</span><span style="font-variant-ligatures:no-common-ligatures">.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(79,129,135)">x</span><span style="font-variant-ligatures:no-common-ligatures"> = x }</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><br class="m_-311399833560624468m_-602078394375739685webkit-block-placeholder"></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,143,1)"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures">required</span><span style="font-variant-ligatures:no-common-ligatures"> </span><span style="font-variant-ligatures:no-common-ligatures">init</span><span style="font-variant-ligatures:no-common-ligatures">(other: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(95,174,174)">Base</span><span style="font-variant-ligatures:no-common-ligatures">)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">                </span>{ </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">self</span><span style="font-variant-ligatures:no-common-ligatures">.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(79,129,135)">x</span><span style="font-variant-ligatures:no-common-ligatures"> = other.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(79,129,135)">x</span><span style="font-variant-ligatures:no-common-ligatures"> }</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">}</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"></span><br></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">class</span><span style="font-variant-ligatures:no-common-ligatures"> Derived: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(95,174,174)">Base</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">{</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(91,38,153)"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">var</span><span style="font-variant-ligatures:no-common-ligatures"> y: </span><span style="font-variant-ligatures:no-common-ligatures">String</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><br class="m_-311399833560624468m_-602078394375739685webkit-block-placeholder"></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">init</span><span style="font-variant-ligatures:no-common-ligatures">(x: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(91,38,153)">Int</span><span style="font-variant-ligatures:no-common-ligatures">, y: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(91,38,153)">String</span><span style="font-variant-ligatures:no-common-ligatures">)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span>{</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">                </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">self</span><span style="font-variant-ligatures:no-common-ligatures">.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(79,129,135)">y</span><span style="font-variant-ligatures:no-common-ligatures"> = y</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">                </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">super</span><span style="font-variant-ligatures:no-common-ligatures">.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">init</span><span style="font-variant-ligatures:no-common-ligatures">(x: x)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span>}</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><br class="m_-311399833560624468m_-602078394375739685webkit-block-placeholder"></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(146,146,146)"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures">// Should be required by the Clonable protocol, but it isn&#39;t.</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,143,1)"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures">required</span><span style="font-variant-ligatures:no-common-ligatures"> </span><span style="font-variant-ligatures:no-common-ligatures">init</span><span style="font-variant-ligatures:no-common-ligatures">(other: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(95,174,174)">Derived</span><span style="font-variant-ligatures:no-common-ligatures">)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span>{</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">                </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">self</span><span style="font-variant-ligatures:no-common-ligatures">.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(79,129,135)">y</span><span style="font-variant-ligatures:no-common-ligatures"> = other.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(79,129,135)">y</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">                </span></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">super</span><span style="font-variant-ligatures:no-common-ligatures">.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">init</span><span style="font-variant-ligatures:no-common-ligatures">(other: other)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span>}</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><br class="m_-311399833560624468m_-602078394375739685webkit-block-placeholder"></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(146,146,146)"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures">// Required because it was `required` in Base.  Even a `Derived` calls this initializer to clone, which is wrong.  Bugs abound.</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,143,1)"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">        </span></span><span style="font-variant-ligatures:no-common-ligatures">required</span><span style="font-variant-ligatures:no-common-ligatures"> </span><span style="font-variant-ligatures:no-common-ligatures">init</span><span style="font-variant-ligatures:no-common-ligatures">(other: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(95,174,174)">Base</span><span style="font-variant-ligatures:no-common-ligatures">)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(2,37,188)"><span style="font-variant-ligatures:no-common-ligatures"><span class="m_-311399833560624468m_-602078394375739685Apple-tab-span" style="white-space:pre-wrap">                </span>{ </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(61,29,129)">fatalError</span><span style="font-variant-ligatures:no-common-ligatures">(</span><span style="font-variant-ligatures:no-common-ligatures">&quot;init(other:) is wrong.&quot;</span><span style="font-variant-ligatures:no-common-ligatures">) }</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">}</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"></span><br></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"></span><br></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span style="font-variant-ligatures:no-common-ligatures"></span><br></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">let</span><span style="font-variant-ligatures:no-common-ligatures"> me = </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(95,174,174)">Derived</span><span style="font-variant-ligatures:no-common-ligatures">(x: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(218,32,0)">1</span><span style="font-variant-ligatures:no-common-ligatures">, y: </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(2,37,188)">&quot;food&quot;</span><span style="font-variant-ligatures:no-common-ligatures">)</span></div><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(146,146,146)"><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,1)">let</span><span style="font-variant-ligatures:no-common-ligatures"> alienClone = </span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(79,129,135)">me</span><span style="font-variant-ligatures:no-common-ligatures">.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(49,89,93)">clone</span><span style="font-variant-ligatures:no-common-ligatures">() </span><span style="font-variant-ligatures:no-common-ligatures">// &quot;init(other:) is wrong.&quot;</span></div><div><br></div></div></pre></div></span></div></div></blockquote><div><br></div><div>Agree. That seems wrong. Great example.</div></div></div></div></div></blockquote><br></div></div></div><div>So, is this odd behavior intentional, a bug, or a design deficiency?  I would think that when a protocol has a method or initializer has `Self` parameters—like in Clonable—every subclass would be required to implement its own specialized version (much like a required initializer).  That would be a special case of the protocol system, though.</div><div><br></div><div>As it sits, even fixing the calling behavior of my example leaves us with the problem of subclasses inheriting inapplicable required initializers from superclasses that actually don’t make any sense.</div><div><br></div><div>Does this deserve its own thread?</div></div></blockquote><div><br></div><div>Dunno, maybe best to have its own thread. It&#39;s not mentioned as part of SE-0068, but IMO a complete design that respects the spirit of that proposal *should* involve allowing you to write:</div><div><br></div><div>```</div><div>class Base : Clonable {</div><div>  required init(other: Self) { ... }</div><div>}</div><div><br></div><div>class Derived : Base {</div><div>  required init(other: Self) { ... }</div><div>}</div><div>```</div><div><br></div></div><br></div></div>