argument type const char* can pass string, buf why const wchar* can not pass wstring

[Basile B. via Digitalmars-d-learn]

On Sunday, 27 December 2015 at 03:34:18 UTC, riki wrote:
> void ccf(const char* str){}
> void cwf(const wchar* str){}
>
> void main()
> {
>     ccf("aaa");    //ok
>     cwf("xxx"w); // error and why ?
> }

IDK but usually the const storage class is used for narrow 
strings because it allows to pass either `char[]` or `string[]`:

```
void ccf(const char[] str){}
void cwf(const wchar[] str){}

void main()
{
     ccf("aaa");
     cwf("xxx"w);
     ccf("aaa".dup);
     cwf("xxx"w.dup);
}
```

I'm actually surprised that one works, maybe both should fail.