SI-6963 Add version to -Xmigration

Adds an optional version parameter to the -Xmigration compiler setting.
Doing -Xmigration without version number behaves as it used to by
dumping every possible migration warning.

This commit adds a ScalaVersion class (plus ancillary stuff), and a
ScalaVersionSetting.

2 files changed, 26 insertions, 0 deletions

diff --git a/test/files/pos/t6963c.flags b/test/files/pos/t6963c.flags
new file mode 100644
index 0000000000..4d6e04914f
--- /dev/null
+++ b/test/files/pos/t6963c.flags
@@ -0,0 +1 @@
+-Xmigration:2.9 -Xfatal-warnings
\ No newline at end of file
diff --git a/test/files/pos/t6963c.scala b/test/files/pos/t6963c.scala
new file mode 100644
index 0000000000..0b6b5c757f
--- /dev/null
+++ b/test/files/pos/t6963c.scala
@@ -0,0 +1,25 @@
+object Test {
+  def f1(x: Any) = x.isInstanceOf[Seq[_]]
+  def f2(x: Any) = x match {
+    case _: Seq[_]  => true
+    case _          => false
+  }
+
+  def f3(x: Any) = x match {
+    case _: Array[_]  => true
+    case _            => false
+  }
+  
+  def f4(x: Any) = x.isInstanceOf[Traversable[_]]
+  
+  def f5(x1: Any, x2: Any, x3: AnyRef) = (x1, x2, x3) match {
+    case (Some(_: Seq[_]), Nil, _)        => 1
+    case (None, List(_: List[_], _), _)   => 2
+    case _                                => 3
+  }
+
+  def f5: Unit = {
+    import scala.collection.mutable._
+    List(1,2,3,4,5).scanRight(0)(_+_)
+  }
+}