Fix default value for ScalaVersionSetting

The default value was NoScalaVersion before, because tryToSet (where
the default was supposed to be set) is not called at all if the option
is not specified.

The initial value of Xmigration is set to NoScalaVersion (which it was
before, the AnyScalaVersion argument was ignored). AnyScalaVersion
would be wrong, it would give a warning in `Map(1 -> "eis").values`
if the option was not specified. See tests.

3 files changed, 84 insertions, 0 deletions

diff --git a/test/files/run/xMigration.check b/test/files/run/xMigration.check
new file mode 100644
index 0000000000..378f7bb6c3
--- /dev/null
+++ b/test/files/run/xMigration.check
@@ -0,0 +1,49 @@
+Type in expressions to have them evaluated.
+Type :help for more information.
+
+scala> Map(1 -> "eis").values    // no warn
+res0: Iterable[String] = MapLike(eis)
+
+scala> :setting -Xmigration:none
+
+scala> Map(1 -> "eis").values    // no warn
+res1: Iterable[String] = MapLike(eis)
+
+scala> :setting -Xmigration:any
+
+scala> Map(1 -> "eis").values    // warn
+<console>:8: warning: method values in trait MapLike has changed semantics in version 2.8.0:
+`values` returns `Iterable[B]` rather than `Iterator[B]`.
+              Map(1 -> "eis").values    // warn
+                              ^
+res2: Iterable[String] = MapLike(eis)
+
+scala> :setting -Xmigration:2.8
+
+scala> Map(1 -> "eis").values    // no warn
+res3: Iterable[String] = MapLike(eis)
+
+scala> :setting -Xmigration:2.7
+
+scala> Map(1 -> "eis").values    // warn
+<console>:8: warning: method values in trait MapLike has changed semantics in version 2.8.0:
+`values` returns `Iterable[B]` rather than `Iterator[B]`.
+              Map(1 -> "eis").values    // warn
+                              ^
+res4: Iterable[String] = MapLike(eis)
+
+scala> :setting -Xmigration:2.11
+
+scala> Map(1 -> "eis").values    // no warn
+res5: Iterable[String] = MapLike(eis)
+
+scala> :setting -Xmigration      // same as :any
+
+scala> Map(1 -> "eis").values    // warn
+<console>:8: warning: method values in trait MapLike has changed semantics in version 2.8.0:
+`values` returns `Iterable[B]` rather than `Iterator[B]`.
+              Map(1 -> "eis").values    // warn
+                              ^
+res6: Iterable[String] = MapLike(eis)
+
+scala> :quit
diff --git a/test/files/run/xMigration.scala b/test/files/run/xMigration.scala
new file mode 100644
index 0000000000..688e878397
--- /dev/null
+++ b/test/files/run/xMigration.scala
@@ -0,0 +1,19 @@
+import scala.tools.partest.ReplTest
+
+object Test extends ReplTest {
+  def code = """
+Map(1 -> "eis").values    // no warn
+:setting -Xmigration:none
+Map(1 -> "eis").values    // no warn
+:setting -Xmigration:any
+Map(1 -> "eis").values    // warn
+:setting -Xmigration:2.8
+Map(1 -> "eis").values    // no warn
+:setting -Xmigration:2.7
+Map(1 -> "eis").values    // warn
+:setting -Xmigration:2.11
+Map(1 -> "eis").values    // no warn
+:setting -Xmigration      // same as :any
+Map(1 -> "eis").values    // warn
+  """
+}
diff --git a/test/junit/scala/tools/nsc/settings/SettingsTest.scala b/test/junit/scala/tools/nsc/settings/SettingsTest.scala
index eda0c27834..96f83c4c2f 100644
--- a/test/junit/scala/tools/nsc/settings/SettingsTest.scala
+++ b/test/junit/scala/tools/nsc/settings/SettingsTest.scala
@@ -164,4 +164,20 @@ class SettingsTest {
     assertThrows[IllegalArgumentException](check("-m:a,b,-ab")(_ => true), _ contains "'ab' cannot be negated")
     assertThrows[IllegalArgumentException](check("-m:a,ac,-uber,uber")(_ => true), _ contains "'uber' cannot be negated")
   }
+
+  @Test def xSourceTest(): Unit = {
+    def check(expected: String, args: String*): Unit = {
+      val s = new MutableSettings(msg => throw new IllegalArgumentException(msg))
+      val (_, residual) = s.processArguments(args.toList, processAll = true)
+      assert(residual.isEmpty)
+      assertTrue(s.source.value == ScalaVersion(expected))
+    }
+    check(expected = "2.11.0") // default
+    check(expected = "2.11.0", "-Xsource:2.11")
+    check(expected = "2.10",   "-Xsource:2.10.0")
+    check(expected = "2.12",   "-Xsource:2.12")
+    assertThrows[IllegalArgumentException](check(expected = "2.11", "-Xsource"), _ == "-Xsource requires an argument, the syntax is -Xsource:<version>")
+    assertThrows[IllegalArgumentException](check(expected = "2.11", "-Xsource", "2.11"), _ == "-Xsource requires an argument, the syntax is -Xsource:<version>")
+    assertThrows[IllegalArgumentException](check(expected = "2.11", "-Xsource:2.invalid"), _ contains "There was a problem parsing 2.invalid")
+  }
 }