<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Jun 28, 2017, at 14:40, Erica Sadun via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="" 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; -webkit-text-stroke-width: 0px;">The `!!` operator should follow the same semantics as `<font face="Menlo" class="" style="font-size: 11px;">Optional.unsafelyUnwrapped</font>`, which establishes a precedent for this approach:</div><div class="" 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; -webkit-text-stroke-width: 0px;"><br class=""></div><blockquote class="" 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; -webkit-text-stroke-width: 0px; margin: 0px 0px 0px 40px; border: none; padding: 0px;"><div class="">> "<i class="">The unsafelyUnwrapped property provides the same value as the forced unwrap operator (postfix !). However, in optimized builds (-O), no check is performed to ensure that the current instance actually has a value. Accessing this property in the case of a nil value is a serious programming error and could lead to undefined behavior or a runtime error.</i>"</div></blockquote></div></blockquote></div><br class=""><div class="">Note that 'unsafelyUnwrapped' does <i class="">not</i> perform the check in optimized builds (like 'assert'), while '!' does (like 'precondition'). <i class="">If</i> we go with '!!', it should behave like 'precondition', not 'assert'.</div><div class=""><br class=""></div><div class="">Jordan</div></body></html>