From db529d9bff6757c4f2fe139de898fb1dc969a0bd Mon Sep 17 00:00:00 2001
From: odersky <odersky@gmail.com>
Date: Wed, 10 Apr 2024 18:43:06 +0200
Subject: [PATCH] Rewrite reaches tests to fix tasty-cc nightly failures

The reaches.scala pos test failed the nightly with tasty cc since one line violated
the new condition for reaches capabilities. The problem was not discoveed in normal
testing since it used the `List` class, which is capture checked only in the nightly.
We now make the relevant bits of `List` explicit in the test itself, so that it is
always capture checked. The failing line got moved to neg.
---
 tests/neg-custom-args/captures/reaches.check |  5 +++++
 tests/neg-custom-args/captures/reaches.scala | 18 ++++++++++++++++++
 tests/pos-custom-args/captures/reaches.scala | 12 +++++++++++-
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/tests/neg-custom-args/captures/reaches.check b/tests/neg-custom-args/captures/reaches.check
index ee628a212ce7..a1c5a56369e9 100644
--- a/tests/neg-custom-args/captures/reaches.check
+++ b/tests/neg-custom-args/captures/reaches.check
@@ -41,3 +41,8 @@
    |                         Required: File^{id*}
    |
    | longer explanation available when compiling with `-explain`
+-- Error: tests/neg-custom-args/captures/reaches.scala:77:5 ------------------------------------------------------------
+77 |  ps.map((x, y) => compose1(x, y)) // error: cannot mix cap and *
+   |  ^^^^^^
+   |  Reach capability cap and universal capability cap cannot both
+   |  appear in the type [B](f: ((box A ->{ps*} A, box A ->{ps*} A)) => B): List[B] of this expression
diff --git a/tests/neg-custom-args/captures/reaches.scala b/tests/neg-custom-args/captures/reaches.scala
index 8ba7f60d6335..de5e4362cdf2 100644
--- a/tests/neg-custom-args/captures/reaches.scala
+++ b/tests/neg-custom-args/captures/reaches.scala
@@ -59,3 +59,21 @@ def attack2 =
   val leaked = usingFile[File^{id*}]: f =>
     val f1: File^{id*} = id(f) // error
     f1
+
+class List[+A]:
+  def head: A = ???
+  def tail: List[A] = ???
+  def map[B](f: A => B): List[B] = ???
+  def nonEmpty: Boolean = ???
+
+extension [A](x: A) def :: (xs: List[A]): List[A] = ???
+
+object Nil extends List[Nothing]
+
+def compose1[A, B, C](f: A => B, g: B => C): A ->{f, g} C =
+  z => g(f(z))
+
+def mapCompose[A](ps: List[(A => A, A => A)]): List[A ->{ps*} A] =
+  ps.map((x, y) => compose1(x, y)) // error: cannot mix cap and *
+
+
diff --git a/tests/pos-custom-args/captures/reaches.scala b/tests/pos-custom-args/captures/reaches.scala
index 0f7df02e13b1..f17c25712c39 100644
--- a/tests/pos-custom-args/captures/reaches.scala
+++ b/tests/pos-custom-args/captures/reaches.scala
@@ -10,6 +10,16 @@ class Ref[T](init: T):
   def get: T = x
   def set(y: T) = { x = y }
 
+class List[+A]:
+  def head: A = ???
+  def tail: List[A] = ???
+  def map[B](f: A -> B): List[B] = ???
+  def nonEmpty: Boolean = ???
+
+extension [A](x: A) def :: (xs: List[A]): List[A] = ???
+
+object Nil extends List[Nothing]
+
 def runAll(xs: List[Proc]): Unit =
   var cur: List[() ->{xs*} Unit] = xs  // OK, by revised VAR
   while cur.nonEmpty do
@@ -36,7 +46,7 @@ def compose2[A, B, C](f: A => B, g: B => C): A => C =
   z => g(f(z))
 
 def mapCompose[A](ps: List[(A => A, A => A)]): List[A ->{ps*} A] =
-  ps.map((x, y) => compose1(x, y))
+  ps.map((x, y) => compose1(x, y)) // Does not work if map takes an impure function, see reaches in neg
 
 @annotation.capability class IO