LSP should not allow to rename things defined in other package

After stdlib things appeared in get scope, if I create a.mligo with

let q : bool = assert true

I can rename (using F2 button in vscode) assert, true and even bool, but prepare rename should forbid me to do this

Now it forbids renaming only renaming of a type like string which has no definition.

It would be nice to fix go to definition (so it temporarily returns None) for such things simultaneously.