Make the class APersistentVector.SubVector public
The patch marks APersistentVector.SubVector public so that it can be used as a type hint for reflection-free access to subvec internals. I missed this in CLJ-1150.
core.rrb-vector needs access to the internals of the built-in vector types in order to support their efficient concatenation and (true, RRB-style) slicing.
Screened by: Alex Miller
This is the exact spot where I'm trying to get at SubVector internals in core.rrb-vector:
With 1.6.0-alpha3, (fv/catvec (subvec [0 1 2 3] 1 2) [:foo]) results in IllegalAccessError tried to access class clojure.lang.APersistentVector$SubVector from class clojure.core.rrb_vector.rrbt$eval2476$fn__2477 clojure.core.rrb-vector.rrbt/eval2476/fn--2477 (rrbt.clj:978). With this patch applied, it works as expected, returning [1 :foo].