Hi Ambrose.
Getting an internal error destructuring an hvec:
user=> (t/cf (t/fn [x :- (t/Option '[t/Num])] (let [[a] x] a)))
Type Error (/tmp/form-init7108876469087894463.clj:1:40) Internal Error (/tmp/form-init7108876469087894463.clj:1:40) Bad call to path-type: nil, ({:idx 0})