Merge pull request #4974 from szeiger/wip/patmat-outertest

More conservative optimization for unnecessary outer ref checks

1 files changed, 106 insertions, 0 deletions

diff --git a/test/files/neg/outer-ref-checks.scala b/test/files/neg/outer-ref-checks.scala
new file mode 100644
index 0000000000..35983fe92b
--- /dev/null
+++ b/test/files/neg/outer-ref-checks.scala
@@ -0,0 +1,106 @@
+import scala.annotation.unchecked.uncheckedVariance
+
+class Outer {
+  // A final class gets no outer ref, so we expect to see warnings where an outer ref check should be performed
+  final case class Inner(val s: String) // unchecked warning
+
+  def belongs(a: Any): Unit = a match {
+    case Inner(s) => // unchecked warning
+    case _ =>
+  }
+
+  def belongsStaticSameOuter(a: Inner): Unit = a match {
+    case Inner(s) => // no need for outer check
+    // match is exhaustive, no default case needed
+  }
+
+  def belongsOtherOuter(a: Outer#Inner): Unit = a match {
+    case Inner(s) => // unchecked warning
+    case O.Inner(s) => // unchecked warning
+    case _ =>
+  }
+}
+
+object O extends Outer {
+  def belongsStaticSameOuter2(a: Inner): Unit = a match {
+    case Inner(s) => // no need for outer check
+    // match is exhaustive, no default case needed
+  }
+
+  def belongsStaticSameOuter3(a: Inner): Unit = a match {
+    case _: Inner => // no need for outer check
+    // match is exhaustive, no default case needed
+  }
+
+  def belongsStaticSameOuter4(a: Inner): Unit = a match {
+    case _: (Inner @uncheckedVariance) => // no need for outer check
+    // match is exhaustive, no default case needed
+  }
+
+  def belongsOtherOuter2(a: Outer#Inner): Unit = a match {
+    case Inner(s) => // unchecked warning
+    case _ =>
+  }
+
+  def belongsOtherOuter3(a: Outer#Inner): Unit = a match {
+    case _: Inner => // unchecked warning
+    case _ =>
+  }
+
+  def belongsOtherOuter4(a: Outer#Inner): Unit = a match {
+    case _: (Inner @unchecked) => // warning supressed
+    case _ =>
+  }
+
+  def belongsOtherOuter5(a: Outer#Inner): Unit = a match {
+    case _: (Inner @uncheckedVariance) => // unchecked warning
+    case _ =>
+  }
+
+  def nested: Unit = {
+    final case class I(s: String)
+
+    def check1(a: Any): Unit = a match {
+      case I(s) => // no need for outer check
+      case _ =>
+    }
+
+    def check2(a: I): Unit = a match {
+      case I(s) => // no need for outer check
+      // match is exhaustive, no default case needed
+    }
+  }
+}
+
+class O2 {
+  def nested: Unit = {
+    final case class I(s: String)
+
+    def check1(a: Any): Unit = a match {
+      case I(s) => // no need for outer check (is this correct?)
+      case _ =>
+    }
+
+    def check2(a: I): Unit = a match {
+      case I(s) => // no need for outer check (is this correct?)
+      // match is exhaustive, no default case needed
+    }
+  }
+}
+
+package p {
+  object T {
+    case class C(x: Int)
+  }
+}
+
+object U {
+  val T = p.T
+}
+
+class Test {
+  def m(a: Any) = a match {
+    case U.T.C(1) => 1  // used to warn
+    case _ => 1
+  }
+}