Optional(T*)
T*
We already did this translation in the other direction, but we had no mapping from `Optional(T)` to anything, so round-tripping a nullable pointer from C++ through Carbon and back to C++ was previously rejected.
ref
addr
import Cpp;
Cpp
Core.CppCompat.Long32
Cpp.long
long
import Cpp inline "some code";
intN_t
uintN_t
none.carbon
CppVoidType