<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">No problem, that still works, because the most specific implementation is chosen:<div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 13px; line-height: normal; font-family: Menlo; color: rgb(131, 148, 150);" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">protocol</span><span style="font-variant-ligatures: no-common-ligatures" class=""> A { </span><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">func</span><span style="font-variant-ligatures: no-common-ligatures" class=""> foo()}</span></div><div style="margin: 0px; line-height: normal; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">protocol</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> B {} </span><span style="font-variant-ligatures: no-common-ligatures" class="">// empty protocol</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; color: rgb(133, 153, 1);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">extension</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">A</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> {</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">func</span><span style="font-variant-ligatures: no-common-ligatures" class=""> foo() {</span></div><div style="margin: 0px; line-height: normal; color: rgb(41, 161, 152);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"Self is A"</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">)</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; color: rgb(133, 153, 1);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">extension</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">A</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">where</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">Self</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">: B {</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">func</span><span style="font-variant-ligatures: no-common-ligatures" class=""> foo() {</span></div><div style="margin: 0px; line-height: normal; color: rgb(41, 161, 152);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"Self is B"</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">)</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">// Works</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">struct</span><span style="font-variant-ligatures: no-common-ligatures" class=""> S1: </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">A</span><span style="font-variant-ligatures: no-common-ligatures" class="">, </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">B</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {}</span></div><div style="margin: 0px; line-height: normal; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">S1</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">().</span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">foo</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">() </span><span style="font-variant-ligatures: no-common-ligatures" class="">// Self is B</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">struct</span><span style="font-variant-ligatures: no-common-ligatures" class=""> S2: </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">A</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {}</span></div><div style="margin: 0px; line-height: normal; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">S2</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">().</span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">foo</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">() </span><span style="font-variant-ligatures: no-common-ligatures" class="">// Self is A</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">// Wu's example works, too</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">struct</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ThirdParty {</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">func</span><span style="font-variant-ligatures: no-common-ligatures" class=""> foo() {</span></div><div style="margin: 0px; line-height: normal; color: rgb(41, 161, 152);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"Self is ThirdParty"</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">)</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; color: rgb(181, 137, 1);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">extension</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">ThirdParty</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> : </span><span style="font-variant-ligatures: no-common-ligatures" class="">A</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> {}</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">ThirdParty</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">().</span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">foo</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">() </span><span style="font-variant-ligatures: no-common-ligatures" class="">// Self is ThirdParty</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">// dynamic dispatch works, too</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">let</span><span style="font-variant-ligatures: no-common-ligatures" class=""> a1: </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">A</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">S1</span><span style="font-variant-ligatures: no-common-ligatures" class="">()</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">a1</span><span style="font-variant-ligatures: no-common-ligatures" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">foo</span><span style="font-variant-ligatures: no-common-ligatures" class="">()</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="color: rgb(88, 110, 117); font-variant-ligatures: no-common-ligatures;" class="">// Self is B</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">let</span><span style="font-variant-ligatures: no-common-ligatures" class=""> a2: </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">A</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures; color: #b58901" class="">S2</span><span style="font-variant-ligatures: no-common-ligatures" class="">()</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">a2</span><span style="font-variant-ligatures: no-common-ligatures" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">foo</span><span style="font-variant-ligatures: no-common-ligatures" class="">()</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="color: rgb(88, 110, 117); font-variant-ligatures: no-common-ligatures;" class="">// Self is A</span></div><div style="margin: 0px; line-height: normal; min-height: 15px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; line-height: normal; color: rgb(181, 137, 1);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #859901" class="">let</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> a3: </span><span style="font-variant-ligatures: no-common-ligatures" class="">A</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures" class="">ThirdParty</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">()</span><span style="color: rgb(131, 148, 150); font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="color: rgb(88, 110, 117); font-variant-ligatures: no-common-ligatures;" class="">// Self is ThirdParty</span></div><div style="margin: 0px; line-height: normal; color: rgb(108, 113, 196);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">a3</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">.</span><span style="font-variant-ligatures: no-common-ligatures" class="">foo</span><span style="font-variant-ligatures: no-common-ligatures; color: #839496" class="">()</span></div></div><div style="margin: 0px; font-size: 13px; line-height: normal; font-family: Menlo; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div style="margin: 0px; font-size: 13px; line-height: normal; font-family: Menlo; color: rgb(88, 110, 117);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div style="margin: 0px; font-size: 13px; line-height: normal; font-family: Menlo; color: rgb(88, 110, 117);" class=""><span style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px;" class="">-Thorsten</span></div><div style="margin: 0px; font-size: 13px; line-height: normal; font-family: Menlo; color: rgb(88, 110, 117);" class=""><span style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px;" class=""><br class=""></span></div><div style="margin: 0px; font-size: 13px; line-height: normal; font-family: Menlo; color: rgb(88, 110, 117);" class=""><span style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px;" class=""><br class=""></span></div><div><blockquote type="cite" class=""><div class="">Am 29.04.2016 um 17:20 schrieb Erica Sadun <<a href="mailto:erica@ericasadun.com" class="">erica@ericasadun.com</a>>:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">In Wux's example, he has third party code:</div><div class=""><br class=""></div><div class="">```</div><div class="">Type ThirdParty {</div><div class=""> func foo() { print("from third party") }</div><div class="">}</div><div class="">```</div><div class=""><br class=""></div><div class="">Then in his own code, he defines protocol A and extends it:</div><div class=""><br class=""></div><div class=""><div dir="auto" class=""><div class=""><div class=""><div class="" style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; color: rgb(187, 44, 162);"><span class="" style="font-variant-ligatures: no-common-ligatures;">extension</span><span class="" style="font-variant-ligatures: no-common-ligatures;"> </span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(79, 129, 135);">A</span><span class="" style="font-variant-ligatures: no-common-ligatures;"> {</span></div><div class="" style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo;"><span class="" style="font-variant-ligatures: no-common-ligatures;"> </span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(187, 44, 162);">func</span><span class="" style="font-variant-ligatures: no-common-ligatures;"> foo() {</span></div><div class="" style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);"><span class="" style="font-variant-ligatures: no-common-ligatures;"> </span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(61, 29, 129);">print</span><span class="" style="font-variant-ligatures: no-common-ligatures;">(</span><span class="" style="font-variant-ligatures: no-common-ligatures;">"Self is B"</span><span class="" style="font-variant-ligatures: no-common-ligatures;">)</span></div><div class="" style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo;"><span class="" style="font-variant-ligatures: no-common-ligatures;"> }</span></div><div class="" style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo;"><span class="" style="font-variant-ligatures: no-common-ligatures;">}</span></div></div></div></div><br class=""></div><div class="">and conforms ThirdParty to A. But he wants the original foo() implementation. Your approach</div><div class="">for writing an extension for plain A without a where clause doesn't offer that solution. The goal</div><div class="">here is "Add this default behavior *only* where a type does not conform to B"</div><div class=""><br class=""></div><div class="">-- E</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><blockquote type="cite" class=""><div class="">On Apr 29, 2016, at 9:10 AM, Thorsten Seitz <<a href="mailto:tseitz42@icloud.com" class="">tseitz42@icloud.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="content-type" content="text/html; charset=utf-8" class=""><div dir="auto" class=""><div class=""></div><div class="">Just writing an extension for plain A without a where clause works.</div><div class=""><br class=""></div><div class="">-Thorsten </div><div class=""><br class="">Am 29.04.2016 um 16:03 schrieb Erica Sadun via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>>:<br class=""><br class=""></div><blockquote type="cite" class=""><div class=""><meta http-equiv="Content-Type" content="text/html charset=us-ascii" class="">Gmane is down as far as my browser is concerned and I haven't found anything by Googling.<div class=""><br class=""></div><div class="">Given the following:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; color: rgb(187, 44, 162);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">protocol</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> A {</span><span style="font-variant-ligatures: no-common-ligatures" class="">func</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> foo()}</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">protocol</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> B {} </span><span style="font-variant-ligatures: no-common-ligatures" class="">// empty protocol</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; min-height: 21px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; color: rgb(187, 44, 162);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">extension</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">A</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">where</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">Self</span><span style="font-variant-ligatures: no-common-ligatures;" class="">:B {</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">func</span><span style="font-variant-ligatures: no-common-ligatures" class=""> foo() {</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #3d1d81" class="">print</span><span style="font-variant-ligatures: no-common-ligatures;" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"Self is B"</span><span style="font-variant-ligatures: no-common-ligatures;" class="">)</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; min-height: 21px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">// Works</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">struct</span><span style="font-variant-ligatures: no-common-ligatures" class=""> S1: </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">A</span><span style="font-variant-ligatures: no-common-ligatures" class="">, </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">B</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {}</span></div><div style="margin: 0px; font-size: 18px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">S1</span><span style="font-variant-ligatures: no-common-ligatures" class="">().</span><span style="font-variant-ligatures: no-common-ligatures; color: #31595d" class="">foo</span><span style="font-variant-ligatures: no-common-ligatures" class="">()</span></div></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">Is there a way to produce a similar extension that exempts any type that conforms to B?</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">cc'ing in Wux because this is a direct response to a scenario he brought up yesterday.</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">-- E</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div></div></blockquote><blockquote type="cite" class=""><div class=""><span class="">_______________________________________________</span><br class=""><span class="">swift-evolution mailing list</span><br class=""><span class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a></span><br class=""><span class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a></span><br class=""></div></blockquote></div></div></blockquote></div><br class=""></div></div></blockquote></div><br class=""></div></body></html>