Merge pull request #798 from dotty-staging/fix-791

Fix 791

Author: DarkDimius

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
       }
   }
 

src/dotty/tools/dotc/typer/Applications.scala

@@ -1117,7 +1117,7 @@ trait Applications extends Compatibility { self: Typer =>
       case cdef: CaseDef => tpd.cpy.CaseDef(cdef)(body = adapt(cdef.body, pt))
       case _ => adaptInterpolated(tree, pt, tree)
     }
-    harmonizeWith(trees)(_.tpe, adapt)
+    if (ctx.isAfterTyper) trees else harmonizeWith(trees)(_.tpe, adapt)
   }
 
   /** If all `types` are numeric value types, and they are not all the same type,

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)
+  }
+}