<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 14 Oct 2014, at 14:21, Sven Barth wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Monaco; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="font-family: monospace; ">At least at first sight there don't seem to be any real (technical) reasons<br>to not covariance for return values.</span></span></blockquote></div><br><div>Delphi and/or FPC already support it to a certain extent, and the compiler contains some code for it (see compatible_childmethod_resultdef in defcmp.pas and its use in nobj.pas). I don't know the exact scenario under which it currently works in though.</div><div><br></div><div><br></div><div>jonas</div></body></html>