Shouldn't type associate on reference instead of its value?<br><br>I agree its syntax is a little suprise : dereferencing an optional without value doesn't throw an error.<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head><body><div class="quote"><br><br>-------- 原始邮件 --------<br>主题：[swift-evolution] [Design Question] Unexpected forced optional unwrapping behavior<br>发件人：Michael Henson via swift-evolution <swift-evolution@swift.org><br>收件人：swift-evolution <swift-evolution@swift.org><br>抄送：<br><br><br type="attribution"><blockquote class="quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">I've spent some time exploring different aspects of the language's type system and came across a case where I wanted to know the type of the thing an optional might hold, if it exists. The direct type of an optional variable is, unsurprisingly, an optional:<div><br></div><div>> var example: String? = "example"</div><div>example: String? = "example"</div><div>> example.dynamicType</div><div>$R1: String?.Type = String?</div><div><br></div><div><br></div><div>Ok, that didn't work. What if I dereference?</div><div><br></div><div>> example!.dynamicType</div><div>$R2: String.Type = String</div><div><br></div><div>Ok. What if the optional doesn't currently have a value? Does this still work?</div><div><br></div><div>> example = nil</div><div>$R3: String.Type = String</div><div><br></div><div>That's odd. I expected it not work, given how forced unwrapping of nil optionals usually turns out.</div><div><br></div><div>Is this explicitly intended behavior, something that really shouldn't work and shouldn't be relied on, or... other?</div><div><br></div><div>Mike</div></div>
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