digitalmars.D.bugs - [Issue 11308] New: Don't use Voldemort types for std.process output
- d-bugmail puremagic.com (57/58) Oct 20 2013 http://d.puremagic.com/issues/show_bug.cgi?id=11308
http://d.puremagic.com/issues/show_bug.cgi?id=11308 Summary: Don't use Voldemort types for std.process output Product: D Version: D2 Platform: All OS/Version: All Status: NEW Severity: normal Priority: P2 Component: Phobos AssignedTo: nobody puremagic.com ReportedBy: andrej.mitrovich gmail.com CC: k.hara.pg gmail.com 13:02:41 PDT --- ----- import std.process; void main() { auto res = executeShell("dmd"); if (res.status) { } if (res.output) { } // ok, reuse variable res = executeShell("rdmd"); if (res.status) { } if (res.output) { } // NG. Even though return types are the same res = execute(["dmd"]); } ----- $ dmd test.dError: cannot implicitly convert expression (execute(["dmd"], null, cast(Config)0, 4294967295u)) of type ProcessOutput to ProcessOutputThe voldemort situation makes reusing variables impossible, even though the same exact type is returned (the only difference being the template is instantiated differently). As a reduced test-case: ----- auto foo(T)() { struct S { int x; } return S(1); } void main() { auto res = foo!int(); res = foo!int(); // NG: Error: cannot implicitly convert expression (foo()) of type S to S res = foo!double(); } ----- This is a borderline compiler bug. Kenji I've CC'ed you to see if this is something worth thinking about, could the compiler be smart enough to deduce that the two Voldemort types are really the same type? But even so, using `auto` for these process functions makes it very hard to figure out what the return type of a function is. We might as well use a proper non-voldemort struct. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 20 2013