In `7`. It's an `int` literal, so `x` has to be an `int`. C++ won't even do you the favor of accounting for the possibility that `x` might have some other type, say, `double`, to which an `int` can be coerced. As for why you would want C++ to infer a different type, consider `std::size_t n = 0;`.
The point is that this is not a type inference, it is a restricted form of a type propagation (i.e., a subset of the pre-auto C++ type propagation, not an extension of it).
