(j3.2006) Question about implicit declaration

[Van Snyder]

8.7p4 says that if the outermost inclusive scope in which an entity
appears is not a type definition it is declared in that scope; otherwise
it is declared in the host of that scope.

Is it possible to declare the type of anything in a type definition
implicitly?

If not, what does "if the outermost inclusive scope in which an entity
appears is not a type definition" contribute?