I like this proposal, I'd also like it if using array.append warned you that you didn't actually call it (maybe it does in swift 2.2).<div><br></div><div>My only cornern is whether the following is ambiguous or not:</div><div> func pop() {}</div><div><font size="2"><span style="background-color:rgba(255,255,255,0)"> </span></font>func pop() -> Int { return 1 }<br><font size="2"><span style="background-color:rgba(255,255,255,0)"> </span></font>pop()<br><br>In my opinion that should call the first pop. Without the first pop that would probably have a warning, yet it is a common case to pop and ignore the value. I know I could do this:</div><div><br></div><div>let _ = pop()</div><div><br></div><div>However that's ugly just to remove the warning.</div><div><br></div><div>I agree with Tino,<span></span> returning Self should probably not have a warning.<br><br>On Friday, 18 December 2015, Tino Heth via swift-evolution <<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div><br><blockquote type="cite"><div><span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">It is a rare case for a result of a function to be unused – and most often it's caused by programmer having too little knowledge of the API.<span> </span></span></div></blockquote></div>I don't think this is a real life problem. When you have a class with something like "append" that doesn't change the receiver but returns a new object, it could be a valuable hint, but I don't like systems which assume that their users don't know what they are doing; and if this is actually the case, you are fighting a tough battle where a little warning wont help.<div><br></div><div>Please also note that ignoring a non-void return value can be absolutely ok in many situations: One example is returning self instead of useless void, which allows to build fluent interfaces - just because Cocoa didn't adopt the concept of method chaining from Smalltalk, it is still a interesting pattern which is used by other frameworks.</div><div><br></div><div>Imho warnings should be reserved for things that can be dangerous, and not to educate programmers...</div>
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