[Issue 20564] Member function increases struct size when the struct is defined in a function

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20564

Simen Kjaeraas <simen.kjaras at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |simen.kjaras at gmail.com
         Resolution|---                         |DUPLICATE

--- Comment #1 from Simen Kjaeraas <simen.kjaras at gmail.com> ---
This is mostly expected. When a nested struct has a method, that method has
access to the context of the function in which it is defined, so you can do
things like this:

void fun() {
    int i = 0;
    struct S {
        void gun() { ++i; }
    }
    S s;
    s.gun();
    assert(i == 1);
}

Since the nested struct may be passed to other functions or even returned from
the function that created it, this context pointer needs to be embedded in the
struct, which explains the size increase - 1 byte for the explicit field, a
context pointer of 8 bytes, and 7 bytes of padding to make sure the pointer is
aligned.

Regardless, in your case the context pointer is strictly unnecessary, and could
be elided. That makes this issue a duplicate of issue 10276.

*** This issue has been marked as a duplicate of issue 10276 ***

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