digitalmars.D.bugs - [Issue 20632] New: Format and writeln not usable with non-copyable
- d-bugmail puremagic.com (40/40) Mar 03 2020 https://issues.dlang.org/show_bug.cgi?id=20632
https://issues.dlang.org/show_bug.cgi?id=20632 Issue ID: 20632 Summary: Format and writeln not usable with non-copyable types Product: D Version: D2 Hardware: x86 OS: Mac OS X Status: NEW Keywords: rejects-valid Severity: enhancement Priority: P1 Component: phobos Assignee: nobody puremagic.com Reporter: pro.mathias.lang gmail.com It is probably the evidence of a larger problem, and fixing it is probably limited by fixes to the ABI, but here it goes: ``` import std.stdio; private struct MyStruct { int a; string b; disable this(this); disable ref MyStruct opAssign(ref MyStruct other); } void main () { MyStruct s; writeln(s); } ``` This code *should* compile. We should be able to take a value by ref and just format or print it. This is quite important when you have `extern(C++)` types where copy is expensive. Even adding my own `toString` to it: ``` string toString() safe pure nothrow nogc { return "WhyNot"; } ``` does not make it compile. --
Mar 03 2020