SI-7791 Line number table reflects underlying file

Since positions ultimately know their ultimate
positions in their ultimate source, use that line
number, ultimately, when emitting line number
table entries.

It is possible, but possibly not useful, to emit
both the actual (ultimate) line number and the
nominal one.

The `int`-valued line number of the `StackTraceElement`
is "derived" from the attribute.

In global, wrapping a `BatchSourceFile` as a
`ScriptSource` happens in `compileSources` to
facilitate testing.

A `ScriptTest` facility is provided to facilitate
testing the script facility. It is rather facile.

3 files changed, 25 insertions, 0 deletions

diff --git a/test/files/run/t7791-script-linenums.check b/test/files/run/t7791-script-linenums.check
new file mode 100644
index 0000000000..b7d969564a
--- /dev/null
+++ b/test/files/run/t7791-script-linenums.check
@@ -0,0 +1 @@
+hello, scripted test
diff --git a/test/files/run/t7791-script-linenums.scala b/test/files/run/t7791-script-linenums.scala
new file mode 100644
index 0000000000..d89b8d4c63
--- /dev/null
+++ b/test/files/run/t7791-script-linenums.scala
@@ -0,0 +1,16 @@
+
+import scala.tools.partest.ScriptTest
+
+object Test extends ScriptTest {
+  object ExceptionLine {
+    def unapply(e: Exception) = Some(e.getStackTrace()(0).getLineNumber)
+  }
+  override def show() = {
+    import util._
+    Try(super.show()) match {
+      case Failure(ExceptionLine(7)) => ()
+      case Failure(e) => e.printStackTrace()
+      case Success(_) => Console println "Expected error"
+    }
+  }
+}
diff --git a/test/files/run/t7791-script-linenums.script b/test/files/run/t7791-script-linenums.script
new file mode 100644
index 0000000000..403dcc2d28
--- /dev/null
+++ b/test/files/run/t7791-script-linenums.script
@@ -0,0 +1,8 @@
+#!/bin/bash
+exec ${SCALA_HOME}/bin/scala "$0" "$@" 2>&1
+!#
+
+Console println s"hello, scripted test"
+
+throw new RuntimeException("failing")  // line 7
+