Visual Assist has problems when unnamed arguments are used in a function's signature. Tested with build 1833.
Using this example:
#include <string>
void f1(const std::string &);
void f2(const std::string &s);
Notice that "string" in function f1 is underlined.
Hovering over "std" in function f1:
Hovering over "std" in function f2:
Hovering over "string" in function f2: