1 files changed, 20 insertions, 18 deletions
diff --git a/lib/std/packedsets.nim b/lib/std/packedsets.nim
index 2b5896be0..3320558f2 100644
--- a/lib/std/packedsets.nim
+++ b/lib/std/packedsets.nim
@@ -12,17 +12,15 @@
 ##
 ## Supports any Ordinal type.
 ##
-## **Note**: Currently the assignment operator `=` for `PackedSet[A]`
-## performs some rather meaningless shallow copy. Since Nim currently does
-## not allow the assignment operator to be overloaded, use the `assign proc
-## <#assign,PackedSet[A],PackedSet[A]>`_ to get a deep copy.
-##
 ## See also
 ## ========
 ## * `sets module <sets.html>`_ for more general hash sets
 
 import std/private/since
-import hashes
+import std/hashes
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
 
 type
   BitScalar = uint
@@ -38,7 +36,7 @@ const
   IntMask = 1 shl IntShift - 1
 
 type
-  Trunk = ref object
+  Trunk {.acyclic.} = ref object
     next: Trunk                                 # all nodes are connected with this pointer
     key: int                                    # start address at bit 0
     bits: array[0..IntsPerTrunk - 1, BitScalar] # a bit vector
@@ -111,7 +109,6 @@ proc intSetPut[A](t: var PackedSet[A], key: int): Trunk =
   t.data[h] = result
 
 proc bitincl[A](s: var PackedSet[A], key: int) {.inline.} =
-  var ret: Trunk
   var t = intSetPut(s, key shr TrunkShift)
   var u = key and TrunkMask
   t.bits[u shr IntShift] = t.bits[u shr IntShift] or
@@ -201,6 +198,7 @@ proc contains*[A](s: PackedSet[A], key: A): bool =
     assert B notin letters
 
   if s.elems <= s.a.len:
+    result = false
     for i in 0..<s.elems:
       if s.a[i] == ord(key): return true
   else:
@@ -409,18 +407,9 @@ proc isNil*[A](x: PackedSet[A]): bool {.inline.} =
 
   x.head.isNil and x.elems == 0
 
-proc assign*[A](dest: var PackedSet[A], src: PackedSet[A]) =
+proc `=copy`*[A](dest: var PackedSet[A], src: PackedSet[A]) =
   ## Copies `src` to `dest`.
   ## `dest` does not need to be initialized by the `initPackedSet proc <#initPackedSet>`_.
-  runnableExamples:
-    var
-      a = initPackedSet[int]()
-      b = initPackedSet[int]()
-    b.incl(5)
-    b.incl(7)
-    a.assign(b)
-    assert len(a) == 2
-
   if src.elems <= src.a.len:
     dest.data = @[]
     dest.max = 0
@@ -449,6 +438,19 @@ proc assign*[A](dest: var PackedSet[A], src: PackedSet[A]) =
       dest.data[h] = n
       it = it.next
 
+proc assign*[A](dest: var PackedSet[A], src: PackedSet[A]) {.inline, deprecated.} =
+  ## Copies `src` to `dest`.
+  ## `dest` does not need to be initialized by the `initPackedSet proc <#initPackedSet>`_.
+  runnableExamples:
+    var
+      a = initPackedSet[int]()
+      b = initPackedSet[int]()
+    b.incl(5)
+    b.incl(7)
+    a.assign(b)
+    assert len(a) == 2
+  `=copy`(dest, src)
+
 proc union*[A](s1, s2: PackedSet[A]): PackedSet[A] =
   ## Returns the union of the sets `s1` and `s2`.
   ##