• Daniel N (13/13) Jul 07 2015 Error: this is not in a class or struct scope
• Tofu Ninja (5/18) Jul 07 2015 Pretty sure that is expected. Default params are evaluated in the
• Meta (6/27) Jul 07 2015 From http://dlang.org/template-mixin.html:

"Daniel N" <ufo orbiting.us> writes:

Error: this is not in a class or struct scope

mixin template NodeT1(T = typeof(this))
{
}
mixin template NodeT2()
{
   alias T = typeof(this);
}

struct Node
{
   mixin NodeT1; // fail
   mixin NodeT2; // pass
}

"Tofu Ninja" <emmons0 purdue.edu> writes:

On Tuesday, 7 July 2015 at 20:08:10 UTC, Daniel N wrote:
 Error: this is not in a class or struct scope

 mixin template NodeT1(T = typeof(this))
 {
 }
 mixin template NodeT2()
 {
   alias T = typeof(this);
 }

 struct Node
 {
   mixin NodeT1; // fail
   mixin NodeT2; // pass
 }

Pretty sure that is expected. Default params are evaluated in the 
declaration scope, so typeof(this) is not defined in NodeT1. The 
only things that break this rule are the special identifiers like 
__FILE__ which are evaluated at the instantiation/call site.

"Meta" <jared771 gmail.com> writes:

On Tuesday, 7 July 2015 at 23:40:55 UTC, Tofu Ninja wrote:
 On Tuesday, 7 July 2015 at 20:08:10 UTC, Daniel N wrote:
 Error: this is not in a class or struct scope

 mixin template NodeT1(T = typeof(this))
 {
 }
 mixin template NodeT2()
 {
   alias T = typeof(this);
 }

 struct Node
 {
   mixin NodeT1; // fail
   mixin NodeT2; // pass
 }

 Pretty sure that is expected. Default params are evaluated in 
 the declaration scope, so typeof(this) is not defined in 
 NodeT1. The only things that break this rule are the special 
 identifiers like __FILE__ which are evaluated at the 
 instantiation/call site.

 From http://dlang.org/template-mixin.html:

Unlike a template instantiation, a template mixin's **body** is 
evaluated within the scope where the mixin appears, not where the 
template declaration is defined.

So it looks like your code is working as intended.