From 24e3a4137fd7b83034ca8a4bfac39a42ab9514e2 Mon Sep 17 00:00:00 2001
From: Kailuo Wang <kailuo.wang@gmail.com>
Date: Thu, 6 Apr 2017 20:42:29 -0400
Subject: [PATCH 1/3] added instances of BitSet to allInstances

---
 core/src/main/scala/cats/instances/all.scala  |  1 +
 .../main/scala/cats/instances/bitSet.scala    | 13 ++++++++++++
 .../main/scala/cats/instances/package.scala   |  1 +
 .../test/scala/cats/tests/BitSetTests.scala   | 21 +++++++++++++++++++
 4 files changed, 36 insertions(+)
 create mode 100644 core/src/main/scala/cats/instances/bitSet.scala
 create mode 100644 tests/src/test/scala/cats/tests/BitSetTests.scala

diff --git a/core/src/main/scala/cats/instances/all.scala b/core/src/main/scala/cats/instances/all.scala
index 18068be967..586d5f287d 100644
--- a/core/src/main/scala/cats/instances/all.scala
+++ b/core/src/main/scala/cats/instances/all.scala
@@ -14,6 +14,7 @@ trait AllInstances
   with    MapInstances
   with    BigIntInstances
   with    BigDecimalInstances
+  with    BitSetInstances
   with    FutureInstances
   with    TryInstances
   with    TupleInstances
diff --git a/core/src/main/scala/cats/instances/bitSet.scala b/core/src/main/scala/cats/instances/bitSet.scala
new file mode 100644
index 0000000000..51d48e63b1
--- /dev/null
+++ b/core/src/main/scala/cats/instances/bitSet.scala
@@ -0,0 +1,13 @@
+package cats.instances
+
+import scala.collection.immutable.BitSet
+import int.catsStdShowForInt
+import cats.syntax.show._
+import cats.Show
+
+trait BitSetInstances extends cats.kernel.instances.BitSetInstances {
+  implicit def catsStdShowForBitSet: Show[BitSet] = new Show[BitSet] {
+    def show(fa: BitSet): String =
+      fa.toIterator.map(_.show).mkString("BitSet(", ", ", ")")
+  }
+}
diff --git a/core/src/main/scala/cats/instances/package.scala b/core/src/main/scala/cats/instances/package.scala
index 8f1a10cad3..d08087f022 100644
--- a/core/src/main/scala/cats/instances/package.scala
+++ b/core/src/main/scala/cats/instances/package.scala
@@ -9,6 +9,7 @@ package object instances {
   object list       extends ListInstances
   object option     extends OptionInstances
   object set        extends SetInstances
+  object bitSet     extends BitSetInstances
   object stream     extends StreamInstances
   object vector     extends VectorInstances
   object map        extends MapInstances
diff --git a/tests/src/test/scala/cats/tests/BitSetTests.scala b/tests/src/test/scala/cats/tests/BitSetTests.scala
new file mode 100644
index 0000000000..ac79dc764c
--- /dev/null
+++ b/tests/src/test/scala/cats/tests/BitSetTests.scala
@@ -0,0 +1,21 @@
+package cats.tests
+
+import org.scalacheck.Arbitrary
+import org.scalacheck.Arbitrary.arbitrary
+
+import scala.collection.immutable.BitSet
+
+class BitSetTests extends CatsSuite {
+  implicit val arbitraryBitSet: Arbitrary[BitSet] =
+    Arbitrary(arbitrary[List[Short]].map(ns => BitSet(ns.map(_ & 0xffff): _*)))
+
+  test("show BitSet"){
+    BitSet(1, 1, 2, 3).show should === ("BitSet(1, 2, 3)")
+    BitSet.empty.show should === ("BitSet()")
+
+    forAll { fs: BitSet =>
+      fs.show should === (fs.toString)
+    }
+  }
+
+}

From 6e3ed2e26647a76109251f8dfb7595da0a1dc4a8 Mon Sep 17 00:00:00 2001
From: Kailuo Wang <kailuo.wang@gmail.com>
Date: Thu, 6 Apr 2017 22:29:08 -0400
Subject: [PATCH 2/3] unnecessary show implementation

---
 core/src/main/scala/cats/instances/bitSet.scala | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/core/src/main/scala/cats/instances/bitSet.scala b/core/src/main/scala/cats/instances/bitSet.scala
index 51d48e63b1..11a64846eb 100644
--- a/core/src/main/scala/cats/instances/bitSet.scala
+++ b/core/src/main/scala/cats/instances/bitSet.scala
@@ -6,8 +6,5 @@ import cats.syntax.show._
 import cats.Show
 
 trait BitSetInstances extends cats.kernel.instances.BitSetInstances {
-  implicit def catsStdShowForBitSet: Show[BitSet] = new Show[BitSet] {
-    def show(fa: BitSet): String =
-      fa.toIterator.map(_.show).mkString("BitSet(", ", ", ")")
-  }
+  implicit def catsStdShowForBitSet: Show[BitSet] = Show.fromToString[BitSet]
 }

From 0ea5608d72f33e5c8d40b19866d6b9537fda5a01 Mon Sep 17 00:00:00 2001
From: Kailuo Wang <kailuo.wang@gmail.com>
Date: Fri, 7 Apr 2017 08:02:22 -0400
Subject: [PATCH 3/3] removed unused imports

---
 core/src/main/scala/cats/instances/bitSet.scala | 2 --
 1 file changed, 2 deletions(-)

diff --git a/core/src/main/scala/cats/instances/bitSet.scala b/core/src/main/scala/cats/instances/bitSet.scala
index 11a64846eb..dc14fe8276 100644
--- a/core/src/main/scala/cats/instances/bitSet.scala
+++ b/core/src/main/scala/cats/instances/bitSet.scala
@@ -1,8 +1,6 @@
 package cats.instances
 
 import scala.collection.immutable.BitSet
-import int.catsStdShowForInt
-import cats.syntax.show._
 import cats.Show
 
 trait BitSetInstances extends cats.kernel.instances.BitSetInstances {