Interesting discussion on the inference, reminds me of Mapping a 'getter' - #16 by Marco_Antoniotti . I guess the problem, and the difference with very fast struct.field is that getproperty cant dispatch on the value of symbol. The constant propagation is neccesary for speed, and constant propagation cannot be counted on (yet) it is only offered as a convenience when it works.
Buuuut it seems to get better every release! Is there a chance that the antipattern will become a pattern in the future? Until then there is Lazy.jl and @forward and other ways of mimicing accessors that can dispatch.