SI-4625 Recognize App in script

Cheap name test: if the script object extends "App",
take it for a main-bearing parent.

Note that if `-Xscript` is not `Main`, the default,
then the source is taken as a snippet and there is
no attempt to locate an existing `main` method.

4 files changed, 18 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index c04d305f9e..7af5c505de 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -380,11 +380,15 @@ self =>
           case DefDef(_, nme.main, Nil, List(_), _, _)  => true
           case _                                        => false
         }
+        def isApp(t: Tree) = t match {
+          case Template(ps, _, _) => ps.exists { case Ident(x) if x.decoded == "App" => true ; case _ => false }
+          case _ => false
+        }
         /* For now we require there only be one top level object. */
         var seenModule = false
         val newStmts = stmts collect {
           case t @ Import(_, _) => t
-          case md @ ModuleDef(mods, name, template) if !seenModule && (md exists isMainMethod) =>
+          case md @ ModuleDef(mods, name, template) if !seenModule && (isApp(template) || md.exists(isMainMethod)) =>
             seenModule = true
             /* This slightly hacky situation arises because we have no way to communicate
              * back to the scriptrunner what the name of the program is.  Even if we were
diff --git a/test/files/run/t4625.check b/test/files/run/t4625.check
new file mode 100644
index 0000000000..e4a4d15b87
--- /dev/null
+++ b/test/files/run/t4625.check
@@ -0,0 +1 @@
+Test ran.
diff --git a/test/files/run/t4625.scala b/test/files/run/t4625.scala
new file mode 100644
index 0000000000..44f6225220
--- /dev/null
+++ b/test/files/run/t4625.scala
@@ -0,0 +1,7 @@
+
+import scala.tools.partest.ScriptTest
+
+object Test extends ScriptTest {
+  // must be called Main to get probing treatment in parser
+  override def testmain = "Main"
+}
diff --git a/test/files/run/t4625.script b/test/files/run/t4625.script
new file mode 100644
index 0000000000..600ceacbb6
--- /dev/null
+++ b/test/files/run/t4625.script
@@ -0,0 +1,5 @@
+
+object Main extends Runnable with App {
+  def run() = println("Test ran.")
+  run()
+}