On Saturday, 1 June 2019 at 21:05:32 UTC, SrMordred wrote:
import std.traits;
struct T { this(ref return scope T other){} }
pragma(msg, hasElaborateCopyConstructor!T); //false
hasElaborateCopyConstructor checks if the type defines a
postblit[0]. That is, a function called this(this). this(T) is
just a regular constructor, and as such does not qualify. From
the documentation[1]:
Elaborate copy constructors are introduced by defining
this(this) for a struct.
Postblits are called after assignment, on the instance being
assigned to, and has no access to the source of the assignment.
If you need access to the source, a ref constructor like yours
will work.
--
Simen
[0]: https://dlang.org/spec/struct.html#struct-postblit
[1]:
https://dlang.org/library/std/traits/has_elaborate_copy_constructor.html
