digitalmars.D.bugs - [Issue 10625] New: Compiler should warn or disallow using slice syntax in initialization
- d-bugmail puremagic.com (41/41) Jul 12 2013 http://d.puremagic.com/issues/show_bug.cgi?id=10625
- d-bugmail puremagic.com (10/10) Jul 12 2013 http://d.puremagic.com/issues/show_bug.cgi?id=10625
http://d.puremagic.com/issues/show_bug.cgi?id=10625 Summary: Compiler should warn or disallow using slice syntax in initialization Product: D Version: D2 Platform: All OS/Version: All Status: NEW Keywords: accepts-invalid Severity: normal Priority: P2 Component: DMD AssignedTo: nobody puremagic.com ReportedBy: andrej.mitrovich gmail.com 09:57:21 PDT --- ----- void main() { int[] source = [0, 1]; int[] arr1 = new int[](2); arr1[] = source[]; assert(arr1 !is source); // ok int[] arr2 = source[]; // looks like a copy assert(arr2 !is arr2); // assert fails: but in fact it's not! } ----- The 'int[] arr2 = source[];' syntax appears as though the source contents are copied into arr2, but in fact this is the same code as 'int[] arr2 = source;'. Since [] has a very special meaning, the above should either: 1) Become an actual deep copy, meaning arr2 would have to allocate space first and then copy contents. This would be a breaking and negative change due to performance implications. 2) Not compile. It looks like a deep copy but it isn't, and this can cause issues down the road (for example using memcpy or even OpenGL functions can create hard to track problems due to using the source and target arrays which point to the same memory). I'd vote heavily towards 2. Of course one can always use 'int[] arr2 = source.dup'. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jul 12 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10625 bearophile_hugs eml.cc changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bearophile_hugs eml.cc Related to Issue 7445 ? -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jul 12 2013