Typedefs are indexed but instances of typedefs are not
typedef struct
{
…
…
} FOO_T;
// somewhere deep within the source tree
FOO_T foo; // create instance of FOO_T type
point at FOO_T and you get a nice popup allowing you to go to the definition…
// somewhere else deep inside the source tree…
foo.xxx = 1;
point at foo and nothing pops up, can not go to the definition of foo