The problem is that joins and projections give rise to new record types. The only way to support this in a type safe and natural way is if you have anonymous re

The problem is that joins and projections give rise to new record types. The only way to support this in a type safe and natural way is if you have anonymous records in the host language, which Rust doesn't. On top of this there is some other metaprogramming stuff that is necessary in order to facilitate the DSL embedding. Look at what Microsoft did with LINQ. You can't pull that off in Rust no matter how much you want to.