More robust scheme for taking start/end of positions when parsing

Some trees, which do not consume input have unassigned positions (so that
they can fit in whatever range they are integrated). It's therefore risky
to take the start or end of a parsed tree's position. This commit guards
against the case where the position of the tree does not exist.

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/neg/i1705.scala b/tests/neg/i1705.scala
new file mode 100644
index 000000000..801adb4b7
--- /dev/null
+++ b/tests/neg/i1705.scala
@@ -0,0 +1,24 @@
+object DepBug {
+  class A {
+    class B
+    def mkB = new B
+    def m(b: B) = b
+  }
+  trait Dep {
+    val a: A
+    val b: a.B
+  }
+  val dep = new {
+    val a = new A
+    val b = a mkB
+  }
+  def useDep(d: Dep) {  // error: procedure syntax
+    import d._
+    a m (b)
+  }
+  {   // error: Null does not take parameters (follow on)
+    import dep._
+    a m (b)
+  }
+  dep.a m (dep b) // error (follow on)
+}