<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 class="">Swift will infer types from the context of an expression as well as the inputs. In this case, although 'Int' and 'String' do not share a type, they are both convertible to 'Any', the argument to 'print'. So because of the call to 'print', 'T' becomes 'Any', and the expression becomes, essentially</div><div class=""><br class=""></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><div class="">print((t1 as Any?) ?? ("asdf" as Any))</div></blockquote><div class=""><br class=""></div><div class="">(Actually, the signature of 'print' is a little more complicated than that, but that's the gist of what's going on.)</div><div class=""><br class=""></div><div class="">Jordan</div><br class=""><div><blockquote type="cite" class=""><div class="">On Apr 18, 2016, at 2:51, tuuranton--- via swift-users <<a href="mailto:swift-users@swift.org" class="">swift-users@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div class="">Why does this compile?</div><div class=""><br class=""></div><div class="">let t1: Int? = 2</div><div class="">print(t1 ?? "asdf")</div><div class=""><br class=""></div><div class="">The type of ?? is this:</div><div class=""><br class=""></div><div class="">@warn_unused_result</div><div class="">public func ??<T>(optional: T?, @autoclosure defaultValue: () throws -> T) rethrows -> T</div><div class=""><br class=""></div><div class="">The type syas that T must be the same type throughout. But above I could successfully use Int? and then String. Why?</div> </div>
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