Merge pull request #3022 from retronym/ticket/7899

 Don't infer by-name types during, e.g. eta-expansion

5 files changed, 32 insertions, 11 deletions

diff --git a/test/files/neg/t7899.check b/test/files/neg/t7899.check
new file mode 100644
index 0000000000..febfe76b8a
--- /dev/null
+++ b/test/files/neg/t7899.check
@@ -0,0 +1,6 @@
+t7899.scala:5: error: type mismatch;
+ found   : Int => Int
+ required: (=> Int) => ?
+    foo(identity)()
+        ^
+one error found
diff --git a/test/files/neg/t7899.scala b/test/files/neg/t7899.scala
new file mode 100644
index 0000000000..f2dea3ab1f
--- /dev/null
+++ b/test/files/neg/t7899.scala
@@ -0,0 +1,7 @@
+object Test {
+  def foo[B](f: (=> Int) => B): () => B = () => f(0)
+
+  def main(args: Array[String]) {
+    foo(identity)()
+  }
+}
diff --git a/test/files/pos/t7584.scala b/test/files/pos/t7584.scala
deleted file mode 100644
index 52d127ecb9..0000000000
--- a/test/files/pos/t7584.scala
+++ /dev/null
@@ -1,11 +0,0 @@
-object Test {
-  def fold[A, B](f: (A, => B) => B) = ???
-  def f[A, B](x: A, y: B): B = ???
-  def bip[A, B] = fold[A, B]((x, y) => f(x, y))
-  def bop[A, B] = fold[A, B](f)
-
-  // these work:
-  fold[Int, Int]((x, y) => f(x, y))
-  fold[Int, Int](f)
-}
-
diff --git a/test/files/run/t7584b.scala b/test/files/run/t7584b.scala
new file mode 100644
index 0000000000..fd560f0418
--- /dev/null
+++ b/test/files/run/t7584b.scala
@@ -0,0 +1,14 @@
+object Test extends App {
+  def fold[A, B](f: (A, => B) => B) = (b: B) => f(null.asInstanceOf[A], b)
+  def f[A, B](x: A, y: B): B = y
+  def bip[A, B] = fold[A, B]((x, y) => f(x, y))
+  def bop[A, B] = fold[A, B](f(_, _))
+
+  // these work:
+  fold[Int, Int]((x, y) => f(x, y))(0)
+  fold[Int, Int](f(_, _))(0)
+
+  // Used to throw a ClassCastException. Since the fix for SI-7899, these issue type errors.
+  // fold[Int, Int](f _)(0)
+  // fold[Int, Int](f)(0)
+}
diff --git a/test/files/run/t7899.scala b/test/files/run/t7899.scala
new file mode 100644
index 0000000000..5879d4b9fe
--- /dev/null
+++ b/test/files/run/t7899.scala
@@ -0,0 +1,5 @@
+object Test extends App {
+  def id[A](a: => A): A = null.asInstanceOf[A]
+  def foo(f: (=> Int) => Int) = () => f(???)
+  foo(id)() // should be allowed and not throw ???
+}