How to dispatch a class function for an object accessed by handle?

Adam D. Ruppe destructionator at
Fri Mar 6 13:47:45 UTC 2020

On Friday, 6 March 2020 at 11:51:54 UTC, wjoe wrote:
> I don't understand this error message. Which type can't be 
> resolved?

I.... don't know. It works if you rename the inner one but it 
doesn't like eponymous templates like this. I suspect either the 
spec subtly doesn't allow it or a compiler bug. I think the type 
it is referring to is the `this` type.

You can work around with an alias:

// test rig
import std.stdio;
struct A {
template opDispatch(string name) {
      auto opDispatch(T, Args...)(Args args) {
            writeln(name, ".", T.stringof, "(", args, ")");

// workaround
void main() {
         A a;
         alias helper = a.opDispatch!("foo");
         a.helper!(int)(5, "omg");

So the helper does one level, then the next level is done on the 
next line to avoid the stupid "multiple ! not allowed". You need 
to specify the `a` again to avoid `need this for...` due to how 
aliases are kinda weird.

Huge hassle to use but if just doing it temporarily to  debug it 
can be livable.

> Is there a way to look at output of what the compiler generates 
> for f.whatever!SomeResource(...); ?

-vcg-ast or something like to dmd but i never use it since 
there's TONS of spam in a file called ``

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