<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=""><div><blockquote type="cite" class=""><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">I think that *all* methods should be available - at least in principle - with associated types </span><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">- replaced by their upper bounds (i.e. Any if no constraints have been given either by the protocol definition itself or th existential) if in covariant position and </div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">- replaced by their lower bounds if in contravariant position</div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">As it is not possible to define lower bounds in Swift, the lower bounds are always the bottom type (called `Nothing` in Swift and not be confused with optionals). The bottom type has no members and therefore a method referencing that type cannot be called and is effectively not available.</div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div></blockquote><div><br class=""></div><div>Thanks for the feedback! So methods that have associated types in contravariant position would have those types be Nothing, unless there was a concrete type bound to that associated type in the Any's where clause?</div><div><br class=""></div><div>Example</div><div><br class=""></div><div>protocol MyProtocol {</div><div> associatedtype AssocType1</div><div> associatedtype AssocType2</div><div> func foo(x: AssocType1, y: AssocType2)</div><div>}</div><div><br class=""></div><div>let a : Any<MyProtocol></div><div>// on 'a', foo is exposed as 'foo(x: Nothing, y: Nothing)', and can thus not be called</div><div><br class=""></div><div>let b : Any<MyProtocol where .AssocType1 == Int></div><div>// on 'b', foo is exposed as 'foo(x: Int, y: Nothing)' and still can't be called</div><div><br class=""></div><div>let c : Any<MyProtocol where .AssocType1 == Int, .AssocType2 == String></div><div>// on 'c', foo is exposed as 'foo(x: Int, y: String)', and can therefore be called</div><div><br class=""></div><div>Let me know if this is what you had in mind.</div><div><br class=""></div><div>Austin</div><br class=""><blockquote type="cite" class=""><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">-Thorsten </div></blockquote></div><br class=""></body></html>