add tests for some edge cases

Author: EugeneFlesselle

tests/run/mirror-defaultArgument/test.scala

@@ -21,3 +21,37 @@ object Test extends App:
     throw IllegalStateException("There should be no default argument")
   catch
     case ex: NoSuchElementException => assert(ex.getMessage == "0") // Ok
+
+
+  case class WithCompanion(s: String = "hello")
+  case object WithCompanion // => mirrors must be anonymous
+
+  val m2 = summon[Mirror.Of[WithCompanion]]
+  assert(m2 ne WithCompanion)
+  assert(m2.defaultArgument(0) == "hello")
+
+
+  class Outer(val i: Int) {
+
+    case class Inner(x: Int, y: Int = i + 1)
+    case object Inner
+
+    val m3 = summon[Mirror.Of[Inner]]
+    assert(m3.defaultArgument(1) == i + 1)
+
+    def localTest(d: Double): Unit = {
+      case class Local(x: Int = i, y: Double = d, z: Double = i + d)
+      case object Local
+
+      val m4 = summon[Mirror.Of[Local]]
+      assert(m4.defaultArgument(0) == i)
+      assert(m4.defaultArgument(1) == d)
+      assert(m4.defaultArgument(2) == i + d)
+    }
+
+  }
+
+  val outer = Outer(3)
+  val m5 = summon[Mirror.Of[outer.Inner]]
+  assert(m5.defaultArgument(1) == 3 + 1)
+  outer.localTest(9d)