Use views in concretization
To concretize, we need the runtime shapes, and to get them, we actually apply the lenses: https://github.com/TuringLang/AbstractPPL.jl/blob/9b64dd89dcde2dc0d8845cd01b4cc305ea83086e/src/varname.jl#L428
It would be good if this were only views. Related: https://github.com/TuringLang/DynamicPPL.jl/issues/341
It would be nice if something like Base.maybeview was implemented for lenses
Yea, I thought about this yesterday after writing. Maybe we can implement some utils locally and then ask the Setfield people whether they want them (although they explicitely exclude new stuff for Setfield, IIRC...)
Fixed by https://github.com/TuringLang/AbstractPPL.jl/pull/43?
No, it's not fixed, the implementation of get uses normal indexing (see linked issue).