internal error when improperly assigning to list column

[MichaelChirico]

Was playing around with #681 and broke something, I guess related to #3310 re: recycling in := assignment:

DT = data.table(a = 1:3)
DT[ , 'c' := .(0, 1, 2)]
DT[ , 'c' := .(rep(0, .N), rep(1, .N))]

Error in [.data.table(DT, , :=("c", .(rep(0, .N), rep(1, .N)))) :
Internal error: recycle length error not caught earlier. slen=2 len=3