Avoid mutating HyLists in hy.contrib

hy/contrib/multi.hy

@@ -84,13 +84,9 @@
      (setv comment (HyString))
      (if (= (type (first bodies)) HyString)
        (setv [comment bodies] (head-tail bodies)))
-     (setv ret `(do))
-     (.append ret '(import [hy.contrib.multi [MultiDispatch]]))
-     (for [body bodies]
-       (setv [let-binds body] (head-tail body))
-       (.append ret 
-                `(with-decorator MultiDispatch (defn ~name ~let-binds ~comment ~@body))))
-     ret)
+     (+ '(do (import [hy.contrib.multi [MultiDispatch]])) (lfor
+       [let-binds #* body] bodies
+       `(with-decorator MultiDispatch (defn ~name ~let-binds ~comment ~@body)))))
     (do
      (setv [lambda-list body] (head-tail bodies))
      `(setv ~name (fn* ~lambda-list ~@body)))))

hy/contrib/walk.hy

@@ -89,7 +89,7 @@ splits a fn argument list into sections based on &-headers.
 returns an OrderedDict mapping headers to sublists.
 Arguments without a header are under None.
 "
-  (setv headers '[&optional &rest &kwonly &kwargs]
+  (setv headers ['&optional '&rest '&kwonly '&kwargs]
         sections (OrderedDict [(, None [])])
         header None)
   (for [arg form]
@@ -169,7 +169,7 @@ Arguments without a header are under None.
                                                 #{})))))
   (defn handle-args-list [self]
     (setv protected #{}
-          argslist `[])
+          argslist [])
     (for [[header section] (-> self (.tail) first lambda-list .items)]
       (if header (.append argslist header))
       (cond [(in header [None '&rest '&kwargs])