Single Abstract Method support: java8 test

Inspired by test/files/run/t7398.scala and sammy_poly.
Added some notes to original tests.

Elaborating on that note: we don't yet desugar `f(a)` to `f.sam(a)`,
like we do for regular functions: `f(a)` becomes `f.apply(a)`.

It seems pleasingly symmetrical and is easy to implement,
but not sure it's a good idea...

1 files changed, 34 insertions, 0 deletions

diff --git a/test/files/run/sammy_java8.scala b/test/files/run/sammy_java8.scala
new file mode 100644
index 0000000000..db9df7f5fe
--- /dev/null
+++ b/test/files/run/sammy_java8.scala
@@ -0,0 +1,34 @@
+import scala.tools.partest._
+
+// java8 version of sammy_poly.scala
+object Test extends CompilerTest {
+  import global._
+
+  override lazy val units: List[CompilationUnit] = {
+    global.settings.Xexperimental.value = true
+
+    // This test itself does not depend on JDK8.
+    javaCompilationUnits(global)(samSource) ++
+    compilationUnits(global)(useSamSource)
+  }
+
+  private def samSource = """
+//   trait F[T, U] { def apply(x: T): U }
+public interface F<T, U> {
+    U apply(T t);
+    default void yadayada() {
+        throw new UnsupportedOperationException("yadayada");
+    }
+}
+  """
+
+  private def useSamSource = """
+class T {
+  def app[T, U](x: T)(f: F[T, U]): U = f(x)
+  app(1)(x => List(x))
+}
+  """
+
+  // We're only checking we can compile it.
+  def check(source: String, unit: global.CompilationUnit): Unit = ()
+}