From a419799f872d5aae99728d711b1ced89e06804a8 Mon Sep 17 00:00:00 2001
From: Paul Phillips <paulp@improving.org>
Date: Wed, 2 Jan 2013 07:09:21 -0800
Subject: SI-6566, unsoundness with alias variance.

This wasn't as bad as it could have been. All these changes
plug soundness holes in trunk. Mostly we're looking at type
aliases which were merely protected when they had to be
protected[this] not to allow unsound variance crossover.
---
 test/files/neg/t6566a.check    |  4 ++++
 test/files/neg/t6566a.scala    | 17 +++++++++++++++++
 test/files/neg/t6566b.check    |  4 ++++
 test/files/neg/t6566b.scala    | 19 +++++++++++++++++++
 test/files/neg/variances.check |  5 ++++-
 5 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 test/files/neg/t6566a.check
 create mode 100644 test/files/neg/t6566a.scala
 create mode 100644 test/files/neg/t6566b.check
 create mode 100644 test/files/neg/t6566b.scala

(limited to 'test/files/neg')

diff --git a/test/files/neg/t6566a.check b/test/files/neg/t6566a.check
new file mode 100644
index 0000000000..7668f9d2fb
--- /dev/null
+++ b/test/files/neg/t6566a.check
@@ -0,0 +1,4 @@
+t6566a.scala:2: error: covariant type T occurs in invariant position in type T of type MyType
+  class TypeCheat[+T] { type MyType = T }
+                             ^
+one error found
diff --git a/test/files/neg/t6566a.scala b/test/files/neg/t6566a.scala
new file mode 100644
index 0000000000..74a0b38e56
--- /dev/null
+++ b/test/files/neg/t6566a.scala
@@ -0,0 +1,17 @@
+object WhatsYourTypeIsMyType {
+  class TypeCheat[+T] { type MyType = T }
+
+  class Foo {
+    val tc = new TypeCheat[Foo]
+    var x: tc.MyType = _
+    def setX() = x = new Foo
+  }
+  class Bar extends Foo {
+    override val tc = new TypeCheat[Bar]
+    def unsound = this
+
+    setX()
+    println(x.unsound)
+  }
+  def main(args: Array[String]): Unit = new Bar
+}
diff --git a/test/files/neg/t6566b.check b/test/files/neg/t6566b.check
new file mode 100644
index 0000000000..fb3fe81fca
--- /dev/null
+++ b/test/files/neg/t6566b.check
@@ -0,0 +1,4 @@
+t6566b.scala:3: error: covariant type T occurs in invariant position in type T of type MyType
+    type MyType = T
+         ^
+one error found
diff --git a/test/files/neg/t6566b.scala b/test/files/neg/t6566b.scala
new file mode 100644
index 0000000000..18ddebf88b
--- /dev/null
+++ b/test/files/neg/t6566b.scala
@@ -0,0 +1,19 @@
+object WhatsYourTypeIsMyType {
+  trait WithMyType[+T] {
+    type MyType = T
+  }
+
+  class Foo extends WithMyType[Foo] {
+    var x: MyType = _
+    def setX() = x = new Foo
+  }
+
+  class Bar extends Foo with WithMyType[Bar] {
+    def unsound { println("iAmABar") }
+
+    setX()
+    println(x.unsound)
+  }
+
+  def main(args: Array[String]): Unit = new Bar
+}
diff --git a/test/files/neg/variances.check b/test/files/neg/variances.check
index 0643e533b7..7d965e94dc 100644
--- a/test/files/neg/variances.check
+++ b/test/files/neg/variances.check
@@ -13,7 +13,10 @@ variances.scala:21: error: covariant type A occurs in invariant position in supe
 variances.scala:74: error: covariant type A occurs in contravariant position in type => test.Covariant.T[A]{val m: A => A} of value x
     val x: T[A] {
         ^
+variances.scala:89: error: covariant type T occurs in invariant position in type T of type A
+    type A = T
+         ^
 variances.scala:90: error: covariant type T occurs in contravariant position in type => test.TestAlias.B[C.this.A] of method foo
     def foo: B[A]
         ^
-6 errors found
+7 errors found
-- 
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