Test case 15772

Author: odersky

tests/neg-custom-args/captures/i15772.check

@@ -0,0 +1,36 @@
+-- [E007] Type Mismatch Error: tests/neg-custom-args/captures/i15772.scala:18:2 ----------------------------------------
+18 |  () => // error
+   |  ^
+   |  Found:    {x} () -> Int
+   |  Required: () -> Int
+19 |    val c : {x} C = new C(x)
+20 |    val boxed1 : (({*} C) => Unit) -> Unit = box1(c)
+21 |    boxed1((cap: {*} C) => unsafe(c))
+22 |    0
+   |
+   | longer explanation available when compiling with `-explain`
+-- [E007] Type Mismatch Error: tests/neg-custom-args/captures/i15772.scala:25:2 ----------------------------------------
+25 |  () => // error
+   |  ^
+   |  Found:    {x} () -> Int
+   |  Required: () -> Int
+26 |    val c : {x} C = new C(x)
+27 |    val boxed2 : Observe[{*} C] = box2(c)
+28 |    boxed2((cap: {*} C) => unsafe(c))
+29 |    0
+   |
+   | longer explanation available when compiling with `-explain`
+-- [E007] Type Mismatch Error: tests/neg-custom-args/captures/i15772.scala:33:37 ---------------------------------------
+33 |  val boxed2 : Observe[{*} C] = box2(c) // error
+   |                                     ^
+   |                                     Found:    {*} C
+   |                                     Required: box {*} C{arg: ? C}
+   |
+   | longer explanation available when compiling with `-explain`
+-- [E007] Type Mismatch Error: tests/neg-custom-args/captures/i15772.scala:44:2 ----------------------------------------
+44 |  x: (() -> Unit) // error
+   |  ^
+   |  Found:    (x : {sayHello, io} () -> Unit)
+   |  Required: () -> Unit
+   |
+   | longer explanation available when compiling with `-explain`

tests/neg-custom-args/captures/i15772.scala

@@ -1,19 +1,44 @@
-class C {
-   def bad() = println("I've gone bad!")
-}
-
-def newC: {*} C = C()
-
 type Observe[T] = (T => Unit) -> Unit
+
 def unsafe(cap: {*} C) = cap.bad()
 
-def box[T](v: T) : Observe[T] = {
+def box1[T](v: T) : (T => Unit) -> Unit = {
   (fn: T => Unit) => fn(v)
 }
 
-def main() : Int = {
-   val boxed : Observe[{*} C] = box(newC)  // error
-   boxed(unsafe)
+def box2[T](v: T) : Observe[T] = {
+  (fn: T => Unit) => fn(v)
+}
 
-   0
+class C(val arg: {*} C) {
+  def bad() = println("I've gone bad!")
 }
+
+def main1(x: {*} C) : () -> Int =
+  () => // error
+    val c : {x} C = new C(x)
+    val boxed1 : (({*} C) => Unit) -> Unit = box1(c)
+    boxed1((cap: {*} C) => unsafe(c))
+    0
+
+def main2(x: {*} C) : () -> Int =
+  () => // error
+    val c : {x} C = new C(x)
+    val boxed2 : Observe[{*} C] = box2(c)
+    boxed2((cap: {*} C) => unsafe(c))
+    0
+
+def main3(x: {*} C) =
+  def c : {*} C = new C(x)
+  val boxed2 : Observe[{*} C] = box2(c) // error
+  boxed2((cap: {*} C) => unsafe(c))
+  0
+
+trait File:
+  def write(s: String): Unit
+
+def main(io: {*} Any) =
+  val sayHello: (({io} File) => Unit) = (file: {io} File) => file.write("Hello World!\r\n")
+  val filesList : List[{io} File] = ???
+  val x = () => filesList.foreach(sayHello)
+  x: (() -> Unit) // error