diff --git a/sjsonnet/src/sjsonnet/stdlib/SetModule.scala b/sjsonnet/src/sjsonnet/stdlib/SetModule.scala
index 65f4a364..614f1b17 100644
--- a/sjsonnet/src/sjsonnet/stdlib/SetModule.scala
+++ b/sjsonnet/src/sjsonnet/stdlib/SetModule.scala
@@ -65,22 +65,19 @@ object SetModule extends AbstractFunctionModule {
     val out = new mutable.ArrayBuilder.ofRef[Lazy]
     // Set a reasonable size hint - in the worst case (no duplicates), we'll need arrValue.length elements
     out.sizeHint(arrValue.length)
-    for (v <- arrValue) {
-      val outResult = out.result()
-      if (outResult.length == 0) {
+
+    var lastAddedKey: Val = null
+    var i = 0
+    while (i < arrValue.length) {
+      val v = arrValue(i)
+      val vKey =
+        if (keyF.isInstanceOf[Val.False]) v.force
+        else keyF.asInstanceOf[Val.Func].apply1(v, pos.noOffset)(ev, TailstrictModeDisabled)
+      if (lastAddedKey == null || !ev.equal(vKey, lastAddedKey)) {
         out.+=(v)
-      } else if (keyF.isInstanceOf[Val.False]) {
-        if (!ev.equal(outResult.last.force, v.force)) {
-          out.+=(v)
-        }
-      } else if (!keyF.isInstanceOf[Val.False]) {
-        val keyFFunc = keyF.asInstanceOf[Val.Func]
-        val o1Key = keyFFunc.apply1(v, pos.noOffset)(ev, TailstrictModeDisabled)
-        val o2Key = keyFFunc.apply1(outResult.last, pos.noOffset)(ev, TailstrictModeDisabled)
-        if (!ev.equal(o1Key, o2Key)) {
-          out.+=(v)
-        }
+        lastAddedKey = vKey
       }
+      i += 1
     }
 
     Val.Arr(pos, out.result())