...to fix it:

```d
alias NS = Nullable!S;
struct S
{
   Nullable!S delegate() f;
}
```

-Steve

...None,S)` then everything works:
```d
struct None {}
struct S
{
    SumType!(None,S) delegate() f;
}
```

...t compile:
```d
struct S
{
    Nullable!S delegate() f;
}
```
Output from DMD:
```
/dlang/dmd/linux...

...Fix 23491 - Nonsensical deprecation message when using delegate" was merged into master:

- d637dfdf254fd7e63b485f6570723849e28e36eb by Dennis...

...safe
{
    toString(null);
}

deprecated
void toString (void delegate (char[]) @safe sink) @safe
{
    char[20] buffer...

...node to the frontend to which we delegate copying `vthis`. The good thing regarding this...

...when using delegate" fixing this issue:

- Fix 23491 - Nonsensical deprecation message when using delegate

https...

...lazy' parameter which I think is a 'delegate'. Perhaps the compiler can use a 'function...

...void foo(A delegate(A) dg){
    writeln("first overload");
}
void foo(B delegate(B) dg...

https://issues.dlang.org/show_bug.cgi?id=23491

Dennis <dkorpel@live.nl> changed:

           What...