Add position check for regression introduced by #2957

The starting bound for ValDefs in #2957 is distinct from the expected result, e.g.

[4:9]val x = [8:9]0
instead of
[0:9]val x = [8:9]0

2 files changed, 56 insertions, 0 deletions

diff --git a/test/files/run/position-val-def.check b/test/files/run/position-val-def.check
new file mode 100644
index 0000000000..a92c77c68c
--- /dev/null
+++ b/test/files/run/position-val-def.check
@@ -0,0 +1,30 @@
+val x = 0
+[0:9]val x = [8:9]0
+
+var x = 0
+[0:9]var x = [8:9]0
+
+val x, y = 0
+[NoPosition]{
+  [0:5]val x = [11]0;
+  [7:12]val y = [11:12]0;
+  [NoPosition]()
+}
+
+var x, y = 0
+[NoPosition]{
+  [0:5]var x = [11]0;
+  [7:12]var y = [11:12]0;
+  [NoPosition]()
+}
+
+val (x, y) = 0
+[NoPosition]{
+  <0:14><synthetic> <artifact> private[this] val x$1 = <4:14>[13:14][13:14]0: @[13]scala.unchecked match {
+    <4:10>case <4:10>[4]scala.Tuple2(<5:6>(x @ [5]_), <8:9>(y @ [8]_)) => <4:10><4:10>scala.Tuple2(<4:10>x, <4:10>y)
+  };
+  [5:6]val x = [5]x$1._1;
+  [8:9]val y = [8]x$1._2;
+  [NoPosition]()
+}
+
diff --git a/test/files/run/position-val-def.scala b/test/files/run/position-val-def.scala
new file mode 100644
index 0000000000..62cb54acf8
--- /dev/null
+++ b/test/files/run/position-val-def.scala
@@ -0,0 +1,26 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.{universe => ru}
+import scala.reflect.runtime.{currentMirror => cm}
+import scala.tools.reflect.ToolBox
+
+object Test {
+  val toolbox = cm.mkToolBox(options = "-Yrangepos")
+
+  def main(args: Array[String]) {
+    def test(expr: String) {
+      val t = toolbox.parse(expr)
+      println(expr)
+      println(show(t, printPositions = true))
+      println()
+    }
+    val tests = """
+    val x = 0
+    var x = 0
+    val x, y = 0
+    var x, y = 0
+    val (x, y) = 0
+    """
+    val exprs = tests.split("\\n").map(_.trim).filterNot(_.isEmpty)
+    exprs foreach test
+  }
+}