Merge pull request #1111 from dotty-staging/fix-#1099

Special case pattern matching against abstract types with class tags

2 files changed, 25 insertions, 38 deletions

diff --git a/tests/neg/arrayclone-new.scala b/tests/neg/arrayclone-new.scala
deleted file mode 100644
index 0e42545f8..000000000
--- a/tests/neg/arrayclone-new.scala
+++ /dev/null
@@ -1,38 +0,0 @@
-// Run with -explaintypes to see information about shadowing failures
-import scala.reflect.{ClassTag, classTag}
-
-object Test extends dotty.runtime.LegacyApp{
-  ObjectArrayClone;
-  PolymorphicArrayClone;
-}
-
-object ObjectArrayClone{
-  val it : Array[String] = Array("1", "0");           // error
-  val cloned = it.clone();
-  assert(cloned.sameElements(it));
-  cloned(0) = "0";
-  assert(it(0) == "1")
-}
-
-object PolymorphicArrayClone{
-  def testIt[T](it : Array[T], one : T, zero : T) = {
-    val cloned = it.clone();
-    assert(cloned.sameElements(it));
-    cloned(0) = zero;
-    assert(it(0) == one)
-  }
-
-  testIt(Array("one", "two"), "one", "two");          // error
-
-  class Mangler[T: ClassTag](ts : T*){
-    // this will always be a BoxedAnyArray even after we've unboxed its contents.
-    val it = ts.toArray[T];
-  }
-
-  val mangled = new Mangler[Int](0, 1);
-
-  val y : Array[Int] = mangled.it; // make sure it's unboxed
-
-  testIt(mangled.it, 0, 1);
-}
-
diff --git a/tests/run/i1099.scala b/tests/run/i1099.scala
new file mode 100644
index 000000000..15a428cc3
--- /dev/null
+++ b/tests/run/i1099.scala
@@ -0,0 +1,25 @@
+import scala.reflect.ClassTag
+object Test {
+  def foo[T: ClassTag](x: Any) =
+    x match {
+      case t: T => true
+      case _   => false
+    }
+  // This is what `foo` expands to
+  def foo2[T](x: Any)(implicit ev: ClassTag[T]) =
+    x match {
+      case t @ ev(_) => true
+      case _   => false
+    }
+  def main(args: Array[String]): Unit = {
+    assert(foo[String]("a"))
+    assert(!foo[String](new Integer(1)))
+    assert(foo[Int](1))
+    assert(!foo[Int](true))
+
+    assert(foo2[String]("a"))
+    assert(!foo2[String](new Integer(1)))
+    assert(foo2[Int](1))
+    assert(!foo2[Int](true))
+  }
+}