std.typecons.Tuple does not support compatible .tupleof args

[dlangBugzillaToGithub]

b2.temp reported this on 2024-11-27T04:40:10Z

Transfered from https://issues.dlang.org/show_bug.cgi?id=24886

CC List

• nick (@ntrel)

Description

In the following code, calls to f2 are all rejected. That is a  bit weird.

```
import std;

struct S
{
    uint a;
    uint b;
}

void f1(uint a, uint b){}
void f2(Tuple!(uint, uint) a){}

void main()
{
    S s;
    uint[2] a;

    f1(s.tupleof); // OK
    f1(a.tupleof); // OK

    f2(s.tupleof); // NG
    f2(a.tupleof); // NG
}  
```

The reason for that is obviously that D does not do implict construction. In case D got first class citizen tuples this would have to work.

[pbackus]

This is not a Phobos bug. std.typecons.Tuple is supposed to do implicit construction, and the given example is not supposed to compile.

Whether or not this will or won't work if/when D gets built-in tuples is irrelevant to Phobos and std.typecons.Tuple.