From 842240f358e30bb88cd821ce12fbf913f734b3d5 Mon Sep 17 00:00:00 2001
From: odersky <odersky@gmail.com>
Date: Thu, 24 Oct 2024 23:41:22 +0200
Subject: [PATCH] More tests

---
 .../src/dotty/tools/dotc/cc/CaptureSet.scala  |  4 ++++
 .../captures/delayedRunops1.scala             | 19 +++++++++++++++++
 .../captures/delayedRunops5.scala             | 21 +++++++++++++++++++
 .../captures/delayedRunops6.scala             | 17 +++++++++++++++
 4 files changed, 61 insertions(+)
 create mode 100644 tests/neg-custom-args/captures/delayedRunops1.scala
 create mode 100644 tests/neg-custom-args/captures/delayedRunops5.scala
 create mode 100644 tests/neg-custom-args/captures/delayedRunops6.scala

diff --git a/compiler/src/dotty/tools/dotc/cc/CaptureSet.scala b/compiler/src/dotty/tools/dotc/cc/CaptureSet.scala
index 51d1328d2ad6..f04c5ce18e41 100644
--- a/compiler/src/dotty/tools/dotc/cc/CaptureSet.scala
+++ b/compiler/src/dotty/tools/dotc/cc/CaptureSet.scala
@@ -821,6 +821,10 @@ object CaptureSet:
         // If this is the union of a constant and a variable,
         // propagate `elem` to the variable part to avoid slack
         // between the operands and the union.
+        // TODO: This means there's no back-propagation to the operands
+        // of a union of two variables. That could be a source of unsoundness.
+        // Altermative would be to be conservatibe and back-propagate to one
+        // of the operands arbitrarily or even to both of them.
         if res.isOK && (origin ne cs1) && (origin ne cs2) then
           if cs1.isConst then cs2.tryInclude(elem, origin)
           else if cs2.isConst then cs1.tryInclude(elem, origin)
diff --git a/tests/neg-custom-args/captures/delayedRunops1.scala b/tests/neg-custom-args/captures/delayedRunops1.scala
new file mode 100644
index 000000000000..17b34e1d01eb
--- /dev/null
+++ b/tests/neg-custom-args/captures/delayedRunops1.scala
@@ -0,0 +1,19 @@
+import language.experimental.captureChecking
+
+def runOps(ops: List[() => Unit]): () ->{ops*} Unit =
+  () => ops.foreach(op => op())
+
+def app[T, U](x: T, op: T => U): () ->{op} U =
+  () => op(x)
+
+def unsafeRunOps2(ops2: List[() => Unit]): () -> () -> Unit =
+  val x = app[List[() ->{ops2*} Unit], () ->{ops2*} Unit](ops2, runOps) // error
+  x
+
+def unsafeRunOps3(ops2: List[() => Unit]): () -> () -> Unit =
+  val x = app(ops2, runOps) // error
+  x
+
+
+
+
diff --git a/tests/neg-custom-args/captures/delayedRunops5.scala b/tests/neg-custom-args/captures/delayedRunops5.scala
new file mode 100644
index 000000000000..3b100ed8f179
--- /dev/null
+++ b/tests/neg-custom-args/captures/delayedRunops5.scala
@@ -0,0 +1,21 @@
+import language.experimental.captureChecking
+
+def runOps(ops: List[() => Unit]): Unit =
+  ops.foreach(op => op())
+
+def app[T, U](x: T, op: T => U): () ->{op} U =
+  () => op(x)
+
+def test(c: Object^) =
+
+  def unsafeRunOps1(ops: List[() ->{c} Unit]): () -> Unit =
+    app[List[() ->{c} Unit], Unit](ops, runOps) // !!! ok, but should be error
+
+  def unsafeRunOps2(ops: List[() ->{c} Unit]): () -> Unit =
+    app(ops, runOps) // error
+
+  ()
+
+
+
+
diff --git a/tests/neg-custom-args/captures/delayedRunops6.scala b/tests/neg-custom-args/captures/delayedRunops6.scala
new file mode 100644
index 000000000000..ab9ac43a8835
--- /dev/null
+++ b/tests/neg-custom-args/captures/delayedRunops6.scala
@@ -0,0 +1,17 @@
+import language.experimental.captureChecking
+
+val runOps: [C^] -> () -> (ops: List[() ->{C^} Unit]) ->{C^} Unit = ???
+
+def app[T, U](x: T, op: T => U): () ->{op} U =
+  () => op(x)
+
+def unsafeRunOps(ops: List[() => Unit]): () ->{} Unit =
+  app[List[() ->{ops*} Unit], Unit](ops, runOps()) // error
+
+def unsafeRunOps2(ops: List[() => Unit]): () ->{} Unit =
+  app(ops, runOps()) // error
+
+def test(c: Object^) =
+  def f = (ops: List[() ->{c} Unit]) => ops.foreach(_())
+  val _: List[() ->{c} Unit] ->{c} Unit = f
+  ()