What other than a pointer can be converted implicitly to const(char)*?

[Shriramana Sharma via Digitalmars-d-learn]

https://github.com/D-Programming-Language/phobos/blob/master/std/conv.d#L878

The `static if` condition here says if something is a pointer and if it is 
implicitly convertible to const(char)*. The isPointer! part seems 
superfluous. Is there something that is not a pointer yet implicitly 
convertible to const(char)*?

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Shriramana Sharma, Penguin #395953