trailing-map.clj

(comment
  ;; original emit on RHS of map destructure form

  (if (seq? kvs)
    (clojure.lang.PersistentHashMap/create (seq kvs))
    kvs)
)

(defn create-bl [& kvs]
  ;; replacement code for RHS of map destructure form
  (if (seq? kvs)
    (if (next kvs)
      (if (odd? (count kvs))
        (conj (clojure.lang.PersistentHashMap/create (butlast kvs)) (last kvs))
        (clojure.lang.PersistentHashMap/create (seq kvs)))
      (first kvs))
    kvs))

(defn create-pt [& kvs]
  ;; replacement code for RHS of map destructure form
  (if (seq? kvs)
    (->> kvs (partition-all 2) (#'clojure.core/spread) (map #(if (seq? %) (vec %) %)) (reduce conj {}))
    kvs))

(defn create-as [& kvs]
  ;; replacement code for RHS of map destructure form
  (if (seq? kvs)
    (persistent! (reduce (fn [acc kv] (if (next kv) (assoc! acc (first kv) (second kv)) (conj! acc (first kv))))
                         (transient {})
                         (partition-all 2 kvs)))
    kvs))

(defn create-tr [& kvs]
  ;; replacement code for RHS of map destructure form
  (if (seq? kvs)
    (loop [m (transient {}) init kvs]
      (if (next init)
        (recur (assoc! m (first init) (second init))
               (-> init next next))
        (persistent! (conj! m (first init)))))
    kvs))

(create-tr :a 1 :b 2 {:c 3})
;;=> {:a 1, :b 2, :c 3}

create-bl - butlast might not be fast but that case might be very uncommon if "seq containing just a map" was separate branch
create-as - what if (second kv) is false?