Fix #791 erasedLub of two AnyVals is Object.

2 files changed, 16 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/core/TypeErasure.scala b/src/dotty/tools/dotc/core/TypeErasure.scala
index 0ef31015c..f27b2fd1e 100644
--- a/src/dotty/tools/dotc/core/TypeErasure.scala
+++ b/src/dotty/tools/dotc/core/TypeErasure.scala
@@ -234,7 +234,11 @@ object TypeErasure {
             case nil =>
               bestSoFar
           }
-          loop(tp1.baseClasses, defn.ObjectClass).typeRef
+          val t = loop(tp1.baseClasses, defn.ObjectClass)
+          if (t eq defn.AnyValClass)
+            // while AnyVal is a valid common super class for primitives it does not exist after erasure
+            defn.ObjectType
+          else t.typeRef
       }
   }
 
diff --git a/tests/run/OrType.scala b/tests/run/OrType.scala
new file mode 100644
index 000000000..9ab805def
--- /dev/null
+++ b/tests/run/OrType.scala
@@ -0,0 +1,11 @@
+class B(val x: Int)
+class C(val x: Double)
+
+object Test{
+  def bar(x: B | C): Int | Double = x.x
+  def main(args: Array[String]): Unit = {
+    val b = new B(1)
+    val c = new C(1)
+    bar(if (b.hashCode > c.hashCode) b else c)
+  }
+}