diff --git a/lib/PriorityQueue.n b/lib/PriorityQueue.n
deleted file mode 100644
index c5ce19f18e..0000000000
--- a/lib/PriorityQueue.n
+++ /dev/null
@@ -1,110 +0,0 @@
-using System.Text;
-using Nemerle;
-using Nemerle.Imperative;
-using Nemerle.Collections;
-using Nemerle.Text;
-using Nemerle.Utility;
-
-using System;
-using System.Collections.Generic;
-
-namespace Nemerle.Collections
-{
-  public class PriorityQueue[T]
-  {
-    private data : List[T] = List();
-    private cmp : T * T -> int;
-
-    public this(cmp : T * T -> int)
-    {
-      this.cmp = cmp;
-    }
-
-    public Enqueue(item : T) : void
-    {
-      data.Add(item);
-      mutable ci = data.Count - 1; // child index; start at end
-      while (ci > 0)
-      {
-        def pi = (ci - 1) / 2; // parent index
-        when (cmp(data[ci], data[pi]) >= 0)
-          break; // child item is larger than (or equal) parent so we're done
-
-        def tmp = data[ci];
-        data[ci] = data[pi];
-        data[pi] = tmp;
-        ci = pi;
-      }
-    }
-
-    public Dequeue() : T
-    {
-      // assumes pq is not empty; up to calling code
-      mutable li = data.Count - 1; // last index (before removal)
-      def frontItem = data[0];   // fetch the front
-      data[0] = data[li];
-      data.RemoveAt(li);
-
-      --li; // last index (after removal)
-      mutable pi = 0; // parent index. start at front of pq
-      while (true)
-      {
-        mutable ci = pi * 2 + 1; // left child index of parent
-        when (ci > li) break;  // no children so done
-        def rc = ci + 1;     // right child
-        when (rc <= li && cmp(data[rc], data[ci]) < 0) // if there is a rc (ci + 1), and it is smaller than left child, use the rc instead
-          ci = rc;
-        when (cmp(data[pi], data[ci]) <= 0)
-          break; // parent is smaller than (or equal to) smallest child so done
-
-        def tmp = data[pi];  // swap parent and child
-        data[pi] = data[ci];
-        data[ci] = tmp;
-        pi = ci;
-      }
-      frontItem;
-    }
-
-    public FrontItem : T
-    {
-      get
-      {
-        def frontItem = data[0];
-        frontItem;
-      }
-    }
-
-    public Count : int
-    {
-      get
-      {
-        data.Count
-      }
-    }
-
-    public override ToString() : string
-    {
-      def sb = StringBuilder();
-      for (mutable i = 0; i < data.Count; ++i)
-        _ = sb.Append(data[i].ToString()).Append(" ");
-      _ = sb.Append("count = ").Append(data.Count);
-      sb.ToString()
-    }
-
-    public IsConsistent() : bool
-    {
-      // is the heap property true for all data?
-      when (data.Count == 0) return true;
-      def li = data.Count - 1; // last index
-      for (mutable pi = 0; pi < data.Count; ++pi) // each parent index
-      {
-        def lci = 2 * pi + 1; // left child index
-        def rci = 2 * pi + 2; // right child index
-
-        when (lci <= li && cmp(data[pi], data[lci]) > 0) return false; // if lc exists and it's greater than parent then bad.
-        when (rci <= li && cmp(data[pi], data[rci]) > 0) return false; // check the right child too.
-      }
-      true; // passed all checks
-    }
-  }
-}