Tightening of position handlng

1) endPos works now even for NoPosition.
2) On the other hand, there's an assertion in Typer.typed which requires every non-empty tree that's type checked in a globally committable context to have a defined position.

Some fixes were needed to make the tests pass the new assert.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/dotty/tools/dotc/util/Positions.scala b/src/dotty/tools/dotc/util/Positions.scala
index 6dfb78c87..21ee788ca 100644
--- a/src/dotty/tools/dotc/util/Positions.scala
+++ b/src/dotty/tools/dotc/util/Positions.scala
@@ -78,13 +78,13 @@ object Positions {
       else this
 
     /** The zero-extent position with start and end at the point of this position */
-    def focus = Position(point)
+    def focus = if (exists) Position(point) else NoPosition
 
     /** The zero-extent position with start and end at the start of this position */
-    def startPos = Position(start)
+    def startPos = if (exists) Position(start) else NoPosition
 
     /** The zero-extent position with start and end at the end of this position */
-    def endPos = Position(end)
+    def endPos = if (exists) Position(end) else NoPosition
 
     /** A copy of this position with a different start */
     def withStart(start: Int) =