I was trying to rename an imported `sqrt` (wrongly), but I stumbled upon this weird behavior:
```
void main() {
    import core.stdc.math: sqrtf, sqrt;
    alias sqrtd = core.stdc.math.sqrt;
    auto a = sqrtd(1);
}
```
onlineapp.d(3): Error: undefined identifier core.stdc.math.sqrt

However, when std.stdio is imported:

```
void main() {
    import std.stdio;
    import core.stdc.math: sqrtf, sqrt;
    alias sqrtd = core.stdc.math.sqrt;
    auto a = sqrtd(1);
}
```
onlineapp.d(4): Deprecation: std.stdio.core is not visible from module onlineapp
onlineapp.d(4): Deprecation: std.stdio.core is not visible from module onlineapp

Apart from the deprecation, it actually works. What is the intended behavior here? Is this a new issue, or does the deprecation already cover it once it becomes an error?

(Btw the correct way to do this is `import core.stdc.math: sqrtf, sqrtd = sqrt;`)

On Sunday, 5 May 2019 at 15:22:31 UTC, Dennis wrote:
> I was trying to rename an imported `sqrt` (wrongly), but I stumbled upon this weird behavior:
> ```
> void main() {
>     import core.stdc.math: sqrtf, sqrt;
>     alias sqrtd = core.stdc.math.sqrt;
>     auto a = sqrtd(1);
> }
> ```
> onlineapp.d(3): Error: undefined identifier core.stdc.math.sqrt


You didn't actually import the name `core` there, only the specific symbols `sqrtf` and `sqrt`, which are now considered direct children of your scope. So it doesn't know where to begin with that fully qualified name - it doesn't know what `core` is.

So this is working as designed by the module and name lookup rules.


The std.stdio one is supposed to be an error; the old buggy behavior was to bypass the private import in these cases and that is why it is deprecated pending changes.

On Sunday, 5 May 2019 at 18:07:10 UTC, Adam D. Ruppe wrote:
> The std.stdio one is supposed to be an error; the old buggy behavior was to bypass the private import in these cases and that is why it is deprecated pending changes.

Thanks, that answers my question. The old private-bypassing behavior is apparently more broken than I thought.