the write() shows a 'null' if the struct has a function/method. why is that?
```
import std.stdio;

void main()
{
	struct S
	{
		int i;
	}
	S s;
	writeln(s);                // S(0)
	writeln(typeid(s).sizeof); // 8
	
	struct S2
	{
		int i;
		this(this){}
	}
	S2 s2;
	import std.conv: to;
	writeln(s2);                // S2(0, null)
	writeln(typeid(s2).sizeof); // 8
}
```

On Sunday, 8 April 2018 at 15:04:49 UTC, number wrote:
> the write() shows a 'null' if the struct has a function/method. why is that?
> ```
> import std.stdio;
>
> void main()
> {
> 	struct S
> 	{
> 		int i;
> 	}
> 	S s;
> 	writeln(s);                // S(0)
> 	writeln(typeid(s).sizeof); // 8
> 	
> 	struct S2
> 	{
> 		int i;
> 		this(this){}
> 	}
> 	S2 s2;
> 	import std.conv: to;
> 	writeln(s2);                // S2(0, null)
> 	writeln(typeid(s2).sizeof); // 8
> }
> ```

S2 is a nested struct [1], which means it has a hidden pointer field that's used to access its enclosing scope. If you change the definition to `static struct S2`, you'll get the same output for both structs.

[1] https://dlang.org/spec/struct.html#nested

On Sunday, 8 April 2018 at 15:51:05 UTC, Paul Backus wrote:
> On Sunday, 8 April 2018 at 15:04:49 UTC, number wrote:
>> 	writeln(s2);                // S2(0, null)
>
> S2 is a nested struct [1], which means it has a hidden pointer field that's used to access its enclosing scope. If you change the definition to `static struct S2`, you'll get the same output for both structs.
>
> [1] https://dlang.org/spec/struct.html#nested

Aha, its the nesting. And if i access the outer scope in the function its not null anymore.
Thank you!