cpp/experimental/any/any cast

Performs type-safe access to the contained object.

For, the program is ill-formed if is not a reference and  is.

Return value
@1@ Returns. @2-3@ Returns. @4-5@ If is not a null pointer, and the  of the requested  matches that of the contents of, a pointer to the value contained by operand, otherwise a null pointer.

Exceptions
@1-3@ Throws if the  of the requested  does not match that of the contents of.