destructors: bugfix: lhs of assignment is irrelevant

compiler/destroyer.nim

@@ -251,8 +251,7 @@ proc p(n: PNode; c: var Con): PNode =
       result = copyNode(n)
       recurse(n, result)
   of nkAsgn, nkFastAsgn:
-    # XXX if special, call special operator
-    if n[0].kind == nkSym and interestingSym(n[0].sym):
+    if hasDestructor(n[0].typ):
       result = moveOrCopy(n[0], n[1], c)
     else:
       result = copyNode(n)