From 6a740332c7bfd56b20993be6ecd0bf818104f56c Mon Sep 17 00:00:00 2001
From: Eugene Burmako <xeno.by@gmail.com>
Date: Thu, 6 Sep 2012 21:05:17 +0200
Subject: SI-6318 fixes ClassTag.unapply for primitives

ClassTag.unapply now has overloads for primitive value classes
so that it can preserve boxiness when performing subtyping tests.

First I wanted to annotate ClassTag.unapply with a ClassTag itself,
i.e. to transform its signature from "def unapply(x: Any): Option[T]"
to "def unapply[U: ClassTag](x: U): Option[T]".

But then virtpatmat_typetag.scala exhibited a nasty problem.
When pattern matching with this unapply, patmat first infers U as something
and then tries to pattern match against this inferred type. And if U gets
inferred as an abstract type itself, bad things happen:
warning: The outer reference in this type test cannot be checked at run time.

That's why I decided to drop the ClassTag idea and go with 9 extra overloads.
Not very beautiful, but definitely robust.
---
 test/files/run/t6318_primitives.scala | 71 +++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 test/files/run/t6318_primitives.scala

(limited to 'test/files/run/t6318_primitives.scala')

diff --git a/test/files/run/t6318_primitives.scala b/test/files/run/t6318_primitives.scala
new file mode 100644
index 0000000000..30f27120b3
--- /dev/null
+++ b/test/files/run/t6318_primitives.scala
@@ -0,0 +1,71 @@
+import scala.reflect.{ClassTag, classTag}
+
+object Test extends App {
+  def test[T: ClassTag](x: T) {
+    println(classTag[T].runtimeClass.isAssignableFrom(x.getClass))
+    println(classTag[T].unapply(x))
+  }
+
+  {
+    val x = 1.toByte
+    println(ClassTag.Byte.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Byte.unapply(x))
+    test(x)
+  }
+
+  {
+    val x = 1.toShort
+    println(ClassTag.Short.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Short.unapply(x))
+    test(x)
+  }
+
+  {
+    val x = 1.toChar
+    println(ClassTag.Char.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Char.unapply(x))
+    test(x)
+  }
+
+  {
+    val x = 1.toInt
+    println(ClassTag.Int.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Int.unapply(x))
+    test(x)
+  }
+
+  {
+    val x = 1.toLong
+    println(ClassTag.Long.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Long.unapply(x))
+    test(x)
+  }
+
+  {
+    val x = 1.toFloat
+    println(ClassTag.Float.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Float.unapply(x))
+    test(x)
+  }
+
+  {
+    val x = 1.toDouble
+    println(ClassTag.Double.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Double.unapply(x))
+    test(x)
+  }
+
+  {
+    val x = true
+    println(ClassTag.Boolean.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Boolean.unapply(x))
+    test(x)
+  }
+
+  {
+    val x = ()
+    println(ClassTag.Unit.runtimeClass.isAssignableFrom(x.getClass))
+    println(ClassTag.Unit.unapply(x))
+    test(x)
+  }
+}
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