• Cauterite (15/15) Aug 17 2016 // ------ Example: ----------
• Adam D. Ruppe (5/8) Aug 17 2016 Function pointers and delegates are not valid compile time
• Cauterite (5/7) Aug 17 2016 I think you missed the point; it works perfectly fine without
• Lodovico Giaretta (4/12) Aug 17 2016 I think he meant that ({ return 0;})() cannot be executed at
• Steven Schveighoffer (4/14) Aug 17 2016 Yes, it can: https://dpaste.dzfl.pl/fca15065a4cf
• Cauterite (4/5) Aug 17 2016 Thanks, I've filed it. Just wanted to get a second opinion before

Cauterite <cauterite gmail.com> writes:

// ------ Example: ----------

template A(alias Arg) {
	enum A = Arg;
	enum Unrelated = ({return 0;})(); // this line prevent 
compilation
};

void main() {
	enum FnPtr = &asdf;
	enum _ = A!FnPtr;
};

void asdf() {};

// ( https://dpaste.dzfl.pl/79301f12e5fc )

Just by having a random `({return 0;})()` in the template body, 
suddenly the template rejects its arguments. I'm so confused, is 
this a bug? Or am I missing something?

Adam D. Ruppe <destructionator gmail.com> writes:

On Wednesday, 17 August 2016 at 13:09:40 UTC, Cauterite wrote:
 Just by having a random `({return 0;})()` in the template body, 
 suddenly the template rejects its arguments. I'm so confused, 
 is this a bug? Or am I missing something?

Function pointers and delegates are not valid compile time 
variables.

Best you can do is use them in an alias argument directly, but 
you cannot use them in an enum argument.

Cauterite <cauterite gmail.com> writes:

On Wednesday, 17 August 2016 at 13:18:06 UTC, Adam D. Ruppe wrote:
 Best you can do is use them in an alias argument directly, but 
 you cannot use them in an enum argument.

I think you missed the point; it works perfectly fine without 
having this `({return 0;})()` in the template body (which, as far 
as I can see, doesn't appear to interact at all with the template 
argument).

Lodovico Giaretta <lodovico giaretart.net> writes:

On Wednesday, 17 August 2016 at 13:21:16 UTC, Cauterite wrote:
 On Wednesday, 17 August 2016 at 13:18:06 UTC, Adam D. Ruppe 
 wrote:
 Best you can do is use them in an alias argument directly, but 
 you cannot use them in an enum argument.

 I think you missed the point; it works perfectly fine without 
 having this `({return 0;})()` in the template body (which, as 
 far as I can see, doesn't appear to interact at all with the 
 template argument).

I think he meant that  ({ return 0;})() cannot be executed at 
compile time and assigned to an enum. That's why the 
instantiation is failing.

Steven Schveighoffer <schveiguy yahoo.com> writes:

On 8/17/16 9:23 AM, Lodovico Giaretta wrote:
 On Wednesday, 17 August 2016 at 13:21:16 UTC, Cauterite wrote:
 On Wednesday, 17 August 2016 at 13:18:06 UTC, Adam D. Ruppe wrote:
 Best you can do is use them in an alias argument directly, but you
 cannot use them in an enum argument.

 I think you missed the point; it works perfectly fine without having
 this `({return 0;})()` in the template body (which, as far as I can
 see, doesn't appear to interact at all with the template argument).

 I think he meant that  ({ return 0;})() cannot be executed at compile
 time and assigned to an enum. That's why the instantiation is failing.

Yes, it can: https://dpaste.dzfl.pl/fca15065a4cf

I think the OP's case is a bug. Please file.

-Steve

Cauterite <cauterite gmail.com> writes:

On Wednesday, 17 August 2016 at 13:33:26 UTC, Steven 
Schveighoffer wrote:
 I think the OP's case is a bug. Please file.

Thanks, I've filed it. Just wanted to get a second opinion before 
concluding that it's a bug.