Need for std.meta.isSame over __traits(isSame)

[user1234]

On Wednesday, 1 September 2021 at 23:04:18 UTC, Per Nordlöw wrote:
> On Wednesday, 1 September 2021 at 22:51:40 UTC, Per Nordlöw 
> wrote:
>> Can somebody explain the need for
>
> Ok, `__traits(isSame)` always returns false for values.
>
> This is very unfortunate as `std.traits.isSame` is one of the 
> most used template instances in typical std.meta-programming 
> and has a noticeable impact on time and space complexity now 
> that AliasAssign-enabled versions of std.meta members have 
> removed the need for other costly recursive template patterns.
>
> I suggest we add a new builtin trait that exactly mimics 
> std.traits.isSame or inline the calls to `isSame` in 
> `std.traits.meta`. This is gonna significantly speed up 
> functions in std.meta, for instance `staticIndexOf`, 
> `EraseAll`, `GenericReplace`, `ReplaceAll`, `Pack`.

I suggest to change the template signature instead:

```d
template isSame(Args...)
if (Args.length == 2)
{
     enum isSame = __traits(isSame, Args[0], Args[1]);
}
```

The problem is not `__traits(isSame)`, it's more the 
TemplateAliasParameter, as observed previously.