Issue 4500 - scoped moves class after calling the constructor

[9rnsr]

By fixing issue 5777, now we can fix issue 4500.

[ckamm]

I've tried it and can verify the two changes make scoped work correctly. I've two unrelated questions:

• Why is there a special case for the no-argument constructor? Shouldn't emplace work for that as well?
• I couldn't break the alignment of the Scoped struct even though typeof(scoped!Someclass()).alignof == 1. How does the code ensure correct alignment?

[9rnsr]

Why is there a special case for the no-argument constructor? Shouldn't emplace work for that as well?

Maybe it is true, but I didn't touch code that is not related to 4500.

I couldn't break the alignment of the Scoped struct even though typeof(scoped!Someclass()).alignof == 1. How does the code ensure correct alignment?

I don't know how to do it.Does current D have the way that set struct object alignment?

class C{}
struct S{}
align(4) struct S2{}
pragma(msg, C.alignof);  // print 4u
pragma(msg, S.alignof);  // print 1u
pragma(msg, S2.alignof);  // still print 1u

[ckamm]

Maybe it is true, but I didn't touch code that is not related to 4500.

Sure, I was just wondering.

I don't know how to do it.Does current D have the way that set struct object alignment?

The align attribute only changes the alignment rules of members of the struct, not the alignment of the struct itself. As far as I know the only way would be something like this:

struct S { union { ulong a; // for alignment ubyte data[instanceSize]; } }