On Friday, 13 October 2017 at 11:21:48 UTC, Biotronic wrote:
On Friday, 13 October 2017 at 10:35:56 UTC, Jack Applegame
wrote:
Compiler creates struct on the stack and silently (without
postblitting and destruction old object) moves it to another
address. Is it normal? I don't think so.
It is. Structs have no identity, and the compiler/GC/whatever
is free to copy and/or move them about as it sees fit (as long
as there is ostensibly only one - no duplicate
constructor/destructor calls, no desynching of state). That's
why the documentation[1] says not to have internal pointers in
structs.
WAT??? Compiler creates struct on the stack copies it without
postblitting and destructs both objects.
Now this looks like a real bug. There should be a this(this)
call in there.
Can I donate to the D Foundation and that my donations would
be aimed at fixing exactly these bugs?
BountySource[2] lets you do basically exactly that.
[1]: https://dlang.org/spec/garbage.html, "Do not have pointers
in a struct instance that point back to the same instance."
[2]: https://www.bountysource.com/
What are the advantages of this weird behavior ?
Also if the object is finally moved then why to call ctor not on
the moved object ?
[1] states that i cannot save the pointer inside the struct on
the same struct(because GC can move objects in the memory, but in
the example there's no gc as objects are on the stack), but what
if i put &this to some global variable ? It should work as
expected, not being partly moved. Postblit should be called as
well as dtor of original object.
1 is a definitely a bug.
