SI-6955 switch emission no longer foiled by type alias

dealiasWiden the type of the scrutinee before checking it's switchable
now with tests! (using IcodeTest since javap is not available everywhere)

rebase of #1879

1 files changed, 28 insertions, 0 deletions

diff --git a/test/files/run/t6955.scala b/test/files/run/t6955.scala
new file mode 100644
index 0000000000..980aa420cc
--- /dev/null
+++ b/test/files/run/t6955.scala
@@ -0,0 +1,28 @@
+import scala.tools.partest.IcodeTest
+
+// this class should compile to code that uses switches (twice)
+class Switches {
+  type Tag = Byte
+
+  def switchBad(i: Tag): Int = i match { // notice type of i is Tag = Byte
+    case 1 => 1
+    case 2 => 2
+    case 3 => 3
+    case _ => 0
+  }
+
+  // this worked before, should keep working
+  def switchOkay(i: Byte): Int = i match {
+    case 1 => 1
+    case 2 => 2
+    case 3 => 3
+    case _ => 0
+  }
+}
+
+object Test extends IcodeTest {
+  // ensure we get two switches out of this -- ignore the rest of the output for robustness
+  // exclude the constant we emit for the "SWITCH ..." string below (we get the icode for all the code you see in this file)
+  override def show() = println(collectIcode("").filter(x => x.indexOf("SWITCH ...") >= 0 && x.indexOf("CONSTANT(") == -1).size)
+}
+