Suggestions only appears when you select the symbol from the pop-up.

[isaacabraham]

if you enter e.g. let x = 5 and then try doing a x., if you didn't "select" x from the pop-up that appears, but simply typed x., you get no suggestions for members on x.

In fact the same applies if you just type System..

[xperiandri]

Really!

[isaacabraham]

Really :-)