diff --git a/bench/src/main/scala-2/cats/collections/bench/BitSetBenchmarks.scala b/bench/src/main/scala-2/cats/collections/bench/BitSetBenchmarks.scala
index 08e79cb6..d39ffe50 100644
--- a/bench/src/main/scala-2/cats/collections/bench/BitSetBenchmarks.scala
+++ b/bench/src/main/scala-2/cats/collections/bench/BitSetBenchmarks.scala
@@ -44,13 +44,13 @@ class BitSetBenchmarks {
   var size: Int = _
   var indices: Array[Int] = _
 
-  var values: Array[Int] = _
+  var values: Vector[Int] = _
   var sci: immutable.BitSet = _
   var scm: mutable.BitSet = _
   var iset: immutable.Set[Int] = _
   var ccbs: _root_.cats.collections.BitSet = _
 
-  var values2: Array[Int] = _
+  var values2: Vector[Int] = _
   var sci2: immutable.BitSet = _
   var scm2: mutable.BitSet = _
   var iset2: immutable.Set[Int] = _
@@ -63,8 +63,8 @@ class BitSetBenchmarks {
     val r = new Random(0x13572468)
 
     values = (0 until size).iterator.filter { _ =>
-      r.nextDouble < density
-    }.toArray
+      r.nextDouble() < density
+    }.toVector
 
     sci = immutable.BitSet(values: _*)
     scm = mutable.BitSet(values: _*)
@@ -72,8 +72,8 @@ class BitSetBenchmarks {
     ccbs = _root_.cats.collections.BitSet(values: _*)
 
     values2 = (0 until size).iterator.filter { _ =>
-      r.nextDouble < density
-    }.toArray
+      r.nextDouble() < density
+    }.toVector
 
     sci2 = immutable.BitSet(values2: _*)
     scm2 = mutable.BitSet(values2: _*)
diff --git a/bench/src/main/scala-2/cats/collections/bench/DietAddBench.scala b/bench/src/main/scala-2/cats/collections/bench/DietAddBench.scala
index f175888a..402e5604 100644
--- a/bench/src/main/scala-2/cats/collections/bench/DietAddBench.scala
+++ b/bench/src/main/scala-2/cats/collections/bench/DietAddBench.scala
@@ -77,16 +77,16 @@ class DietAddBench extends BestCaseRangesList {
 
   @Benchmark
   def scalazDievAdd(): Unit = {
-    scalazValues.foldLeft(Diev.empty[Int])((d, r) => d + r)
+    scalazValues.foldLeft(Diev.empty[Int])((d, r) => d + r): Unit
   }
 
   @Benchmark
   def dogsDietAddRange(): Unit = {
-    dogRanges.foldLeft(Diet.empty[Int])((d, r) => d + Range(r.start, r.end))
+    dogRanges.foldLeft(Diet.empty[Int])((d, r) => d + Range(r.start, r.end)): Unit
   }
 
   @Benchmark
   def scalazDievAddRange(): Unit = {
-    scalazRanges.foldLeft(Diev.empty[Int])((d, r) => d + ((r.start, r.end)))
+    scalazRanges.foldLeft(Diev.empty[Int])((d, r) => d + ((r.start, r.end))): Unit
   }
 }
diff --git a/bench/src/main/scala-2/cats/collections/bench/DietRandomizeBench.scala b/bench/src/main/scala-2/cats/collections/bench/DietRandomizeBench.scala
index 62d78917..57f59f6c 100644
--- a/bench/src/main/scala-2/cats/collections/bench/DietRandomizeBench.scala
+++ b/bench/src/main/scala-2/cats/collections/bench/DietRandomizeBench.scala
@@ -36,29 +36,25 @@ import scala.util.Random
 @State(Scope.Benchmark)
 class DietRandomizeBench extends BigNumberLists {
 
-//  import dogs.Predef._
-
   implicit val scalazEnumInt: Monoid[Int] with Enum[Int] with Show[Int] = scalaz.std.anyVal.intInstance
 
   @Benchmark
   def dogsDietAddRandom(): Unit = {
-    Random.shuffle(scala).foldLeft(Diet.empty[Int])((d, r) => d + r)
+    Random.shuffle(scala).foldLeft(Diet.empty[Int])((d, r) => d + r): Unit
   }
 
   @Benchmark
   def scalazDievAddRandom(): Unit = {
-    Random.shuffle(scalazlst.toList).foldLeft(Diev.empty[Int])((d, r) => d + r)
+    Random.shuffle(scalazlst.toList).foldLeft(Diev.empty[Int])((d, r) => d + r): Unit
   }
 
   @Benchmark
   def dogsDietAddRangeRandom(): Unit = {
-    Random.shuffle(scala).foldLeft(Diet.empty[Int])((d, r) => d + Range(r, r + 10))
+    Random.shuffle(scala).foldLeft(Diet.empty[Int])((d, r) => d + Range(r, r + 10)): Unit
   }
 
   @Benchmark
   def scalazDievAddRangeRandom(): Unit = {
-    var diev = Diev.empty[Int]
-
-    Random.shuffle(scalazlst.toList).foldLeft(Diev.empty[Int])((d, r) => d + ((r, r + 10)))
+    Random.shuffle(scalazlst.toList).foldLeft(Diev.empty[Int])((d, r) => d + ((r, r + 10))): Unit
   }
 }