Merge pull request #4822 from retronym/ticket/9178

SI-9178 Don't eta expand to an Function0-like SAM expected type

4 files changed, 22 insertions, 0 deletions

diff --git a/test/files/pos/t9178.flags b/test/files/pos/t9178.flags
new file mode 100644
index 0000000000..7de3c0f3ee
--- /dev/null
+++ b/test/files/pos/t9178.flags
@@ -0,0 +1 @@
+-Xfatal-warnings -deprecation
diff --git a/test/files/pos/t9178.scala b/test/files/pos/t9178.scala
new file mode 100644
index 0000000000..f2cf20a778
--- /dev/null
+++ b/test/files/pos/t9178.scala
@@ -0,0 +1,13 @@
+// eta expansion to Function0 is problematic (as shown here).
+// Perhaps we should we deprecate it? See discussion in the comments of
+// on SI-9178.
+//
+// This test encodes the status quo: no deprecation.
+object Test {
+  def foo(): () => String = () => ""
+  val f: () => Any = foo
+
+  def main(args: Array[String]): Unit = {
+    println(f()) // <function0>
+  }
+}
diff --git a/test/files/pos/t9178b.flags b/test/files/pos/t9178b.flags
new file mode 100644
index 0000000000..48fd867160
--- /dev/null
+++ b/test/files/pos/t9178b.flags
@@ -0,0 +1 @@
+-Xexperimental
diff --git a/test/files/pos/t9178b.scala b/test/files/pos/t9178b.scala
new file mode 100644
index 0000000000..cbeaed4f17
--- /dev/null
+++ b/test/files/pos/t9178b.scala
@@ -0,0 +1,7 @@
+abstract class Test{
+  val writeInput: java.io.OutputStream => Unit
+  def getOutputStream(): java.io.OutputStream
+
+  writeInput(getOutputStream)
+}
+