<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 23, 2016, at 4:45 PM, Xiaodi Wu 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=""><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="">Let me correct myself: what I think Josh's example is should be corrected whether we prohibit or ignore. However, since no one can see the invisible characters he used, I can't say for sure.</span><br 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 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=""><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="">If he found a clever way to reorder or change spacing between letters (e.g. superimpose two characters so that "var11" looks like "var1"), then the problem can only be fixed by prohibition.</span></div></blockquote></div><br class=""><div class="">I asked my colleague who played the prank on me and got the details:</div><div class=""><br class=""></div><div class="">"Lines 4 and 5 declare variables with embedded Unicode Zero Width Spaces (U+200B) in their names. Line 4 is actually “var\U+200B1”, not “var1”. Isn’t it nice of Swift to be this flexible <span style="line-height: normal; font-family: 'Apple Color Emoji';" class="">😊”</span></div><div class=""><span style="line-height: normal; font-family: 'Apple Color Emoji';" class=""><br class=""></span></div><div class=""><span style="line-height: normal; font-family: 'Apple Color Emoji';" class="">Josh</span></div><div class=""><span style="line-height: normal; font-family: 'Apple Color Emoji';" class=""><br class=""></span></div><div class=""><br class=""></div><div class=""><div class=""><span class="Apple-style-span" style="border-collapse: separate; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; line-height: normal; border-spacing: 0px;"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Josh Wisenbaker</div><div class=""><a href="mailto:macshome@mac.com" class="">macshome@mac.com</a></div><div class=""><br class=""></div></div></span><br class="Apple-interchange-newline"><br class="Apple-interchange-newline"></div></div></body></html>