Drop Override flag for non-overriding direct methods

Also, integrate Jason's test case with the conditional.

Author: odersky

compiler/src/dotty/tools/dotc/transform/ShortcutImplicits.scala

@@ -89,11 +89,14 @@ class ShortcutImplicits extends MiniPhase with IdentityDenotTransformer { thisTr
     }
 
     /** A new `m$direct` method to accompany the given method `m` */
-    private def newDirectMethod(sym: Symbol)(implicit ctx: Context): Symbol =
-      sym.copy(
+    private def newDirectMethod(sym: Symbol)(implicit ctx: Context): Symbol = {
+      val direct = sym.copy(
         name = sym.name.directName,
         flags = sym.flags | Synthetic,
         info = directInfo(sym.info))
+      if (direct.allOverriddenSymbols.isEmpty) direct.resetFlag(Override)
+      direct
+    }
 
     /** The direct method `m$direct` that accompanies the given method `m`.
      *  Create one if it does not exist already.

tests/run/implicitFuns.scala

@@ -1,5 +1,5 @@
 object Test {
-  def main(args: Array[String]) = {
+  def main(args: Array[String]): Unit = {
 
     implicit val world: String = "world!"
 
@@ -53,6 +53,10 @@ object Test {
     val c1: Int = c
 
     Contextual.main(args)
+
+    def foo(s: String): Stringly[Int] = 42
+
+    (if ("".isEmpty) foo("") else foo("")).apply("")
   }
 }