On Saturday, 14 June 2025 at 02:16:58 UTC, Andrey Zherikov wrote:
On Saturday, 14 June 2025 at 02:10:03 UTC, monkyyy wrote:
On Saturday, 14 June 2025 at 01:46:31 UTC, Andrey Zherikov
wrote:
On Saturday, 14 June 2025 at 00:02:32 UTC, Andrey Zherikov
wrote:
Simplified test case a bit more.
This works:
```d
template f(void function(int) F) {}
template f(int function(int) F) {}
mixin f!((int _) {});
mixin f!((int _) => 0);
mixin f!((int) {});
mixin f!((int) => 0);
mixin f!((_) {});
mixin f!((_) => 0); // Error: cannot return non-void from
`void` function
```
Can anyone explain why adding type of the parameter in lambda
(`int`) makes this working?
https://dlang.org/spec/template-mixin.html
Your still mixing syntax; mixin templates are suppose to be a
separate system according to the spec.
```d
import std;
void f(int function(int) F)(){"int".writeln;}
void f(void function(int) F)(){"void".writeln;}
unittest{
f!((_) {});
f!((_) => 0);
}
mixin template g(int function(int) F){string s1="int";}
mixin template g(void function(int) F){string s2="void";}
unittest{
mixin g!((_) {});
mixin g!((_) => 0);
s1.writeln;
s2.writeln;
}
```
Modified your example a bit.
This works:
```d
mixin template f(void function(int) F) { void s1()
{"void".writeln; } }
mixin template f(int function(int) F) { void s2()
{"int".writeln; } }
void main()
{
mixin f!((_) {});
mixin f!((_) => 0);
s1();
s2();
}
```
This does not:
```d
mixin template f(void function(int) F) { void s1()
{"void".writeln; } }
mixin template f(int function(int) F) { void s2()
{"int".writeln; } }
mixin f!((_) {});
mixin f!((_) => 0); // Error: cannot return non-void from
`void` function
void main()
{
s1();
s2();
}
```
```d
import std;
mixin template f(int function(int) F){}
mixin template f(void function(int) F){unittest{"void".writeln;}}
//mixin f!((_){}); //FAILS
mixin template g(void function(int) F){unittest{"void".writeln;}}
mixin template g(int function(int) F){}
mixin g!((_){}); //works
```
this example makes it purely a compiler bug
I cant escape any useful information(I tried `typeof(return)`),
seems to be limited to just void return functions
