A quick example, on a diffraction-limited image.
100% crops (raw-converted with Raw Therapee 3.0alpha and ejmartin's AMaZE algorythm).
On the left a shot taken with a Canon 5DmkII and 135/2L at f/5.6.
On the right, same stuff at f/22.
Both shots unsharpened.
The difference is obvious.
The right image is diffraction-limited (the 135/2L is a very sharp lens).
Second picture: same images, sharpened with R-L deconvolution.
f/5.6 on the left, f/22 on the right.
The f/5.6 shot is still sharper, but look at aliasing artifacts.
The lens transmitted spatial frequencies far beyond the Nyquist limit and the AA filter could not do much about it.
Smaller pattern are totally destroyed by aliasing.
The f/22 is a bit softer, but almost entirely aliasing-free; I'd say that almost all the useable details are there, and smaller patterns are much more gracefully handled.