digitalmars.D.bugs - [Issue 6247] New: Disallow static mutable variables definitions in pure functions
- d-bugmail puremagic.com (44/47) Jul 04 2011 http://d.puremagic.com/issues/show_bug.cgi?id=6247
http://d.puremagic.com/issues/show_bug.cgi?id=6247 Summary: Disallow static mutable variables definitions in pure functions Product: D Version: D2 Platform: All OS/Version: All Status: NEW Keywords: diagnostic Severity: enhancement Priority: P2 Component: DMD AssignedTo: nobody puremagic.com ReportedBy: bearophile_hugs eml.cc This is a spinoff of bug 4031 This program: pure int foo() { static int x = 1; return x; // line 3 } void main() {} In DMD 2.053 it generates an error in returning x: test.d(3): Error: pure function 'foo' cannot access mutable static data 'x' The error message is but I suggest to disallow the definition of static mutable data too, this means disallowing line 2 too. But mutable static variables can't be used in pure functions, so it's better to really disallow them, and produce a compile error at line 2 too, because there's no point in allowing their definition and disallowing just their usage. Some answers to yebblies, from bug 4031:I'm not sure if disabling mutable static variables inside pure functions is valid, as some actions on them (eg. returning their address) do make sense.Returning the address of a static variable defined inside a pure function? I don't see the purpose of this. It smells.They can also be accessed from any statements inside debug {}.But this need is probably uncommon, and when this needs arises you are able to move the definition of such variable inside the debug: pure int foo(int x) { debug { static int y = 10; } return x; } void main() {} -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jul 04 2011