From 7a264eee7c903295693ea14e075267dfceea8db9 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Fri, 6 May 2016 18:59:06 +0200
Subject: Test case

---
 tests/neg/equality.scala | 80 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 tests/neg/equality.scala

(limited to 'tests/neg/equality.scala')

diff --git a/tests/neg/equality.scala b/tests/neg/equality.scala
new file mode 100644
index 000000000..a32db57c5
--- /dev/null
+++ b/tests/neg/equality.scala
@@ -0,0 +1,80 @@
+object equality {
+
+  case class Str(str: String)
+
+  case class Num(x: Int)
+
+  case class Other(x: Int)
+
+  trait Option[+T]
+  case class Some[+T](x: T) extends Option[T]
+  case object None extends Option[Nothing]
+
+  implicit def eqStr: Eq[Str, Str] = Eq()
+  implicit def eqNum: Eq[Num, Num] = Eq()
+  implicit def eqOption[T, U, OT <: Option[T], OU <: Option[U]]
+    (implicit e: Eq[T, U]): Eq[OT, OU] = Eq()
+
+  def main(args: Array[String]): Unit = {
+    Some(Other(3)) == None
+
+    val x = Str("abc")
+    x == x
+
+    val n = Num(2)
+    val m = Num(3)
+    n == m
+
+    Other(1) == Other(2)
+
+    Some(x) == None
+    Some(x) == Some(Str(""))
+    val z: Option[Str] = Some(Str("abc"))
+    z == Some(x)
+    z == None
+    Some(x) == z
+    None == z
+    None == Some(Other(3))
+
+    Other(3) == null
+    Str("x") == null
+    null == Other(3)
+    null == Str("x")
+    null == null
+
+    class Fruit
+
+    implicit def eqFruit[A <: Fruit, B <: Fruit]: Eq[A, B] = Eq()
+
+    class Apple extends Fruit
+    class Pear extends Fruit
+    val a = new Apple
+    val p = new Pear
+    val f: Fruit = a
+    a == p
+    p == a
+    f == p
+    p == f
+    Some(new Apple) == Some(new Pear)
+
+    n match {
+      case None =>   // error
+    }
+
+    x == Other(1)  // error
+    Other(2) == x // error
+    Other(1) == z // error
+    z == Other(1) // error
+    n == None // error
+
+    Some(new Apple) == Some(Str("xx")) // error
+    x == n  // error
+    n == x  // error
+    z == Some(n) // error
+    z == n // error
+    Some(n) == z // error
+    Some(n) == Some(Other(3)) // error
+    Some(Other(3)) == Some(n) // error
+    n == z // error
+  }
+}
-- 
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