_Comment made by: mfikes_
CLJS\-3118.patch converts to {{-with-meta}} in 3 places:
In {{MapEntry}} this appears to be OK as it is being applied to a vector literal.
In {{vec}} and {{set}}, {{with-meta}} is previously applied to values that satisfy {{vector?}} and {{set?}} respectively. Assuming these non-{{nil}} values don't also satisfy {{goog/isFunction}} then {{with-meta}} would then call {{-with-meta}} on them. So, this change could also be a slight perf optimization owing to the inlining and elision of a few checks.
If, on the other hand, a value satisfying {{goog/isFunction}} is passed to {{vec}} or {{set}} and causes the code to follow this path (by satisfying {{vector?}} / {{set?}}), then correctness of the change would also seem to depend on whether that value properly implements {{-with-meta}}. It seems you would only get into this situation if code does odd things like
(extend-type function IVector (-assoc-n [_ _ _]))
or
(extend-type function ISet (-disjoin [_ _]))
