Rename is offered for me when I paste your two source lines into a clean new win32 test project.
Can you please try to do the same? Does it make any difference?
If it works in a new project, does it work in your project if you just paste this two line into it?
class Foo { };
using foo_t = Foo; // Rename is not available for foo_t
Something more is playing a role here, but what could it be? Are you using any "complex" macros? e.g. Macros that calls other macros or macros that create code (setters, getters, or part of the class, defines a namespace, etc.)