Cleanups in TypeApply creation and casting.

There's every hint that it's a requirement that a TypeApply have
non-empty typeArgs, but testing for and handling the empty condition
is done irregularly. Made a mkTypeApply which handles the isEmpty case
(returning "fun" unchanged.) Also unified most of the variations of
casts under one umbrella. Review by moors.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/library/scala/reflect/api/Trees.scala b/src/library/scala/reflect/api/Trees.scala
index 3e5dae739d..64793fb303 100644
--- a/src/library/scala/reflect/api/Trees.scala
+++ b/src/library/scala/reflect/api/Trees.scala
@@ -496,7 +496,10 @@ trait Trees /*extends reflect.generic.Trees*/ { self: Universe =>
   }
 
   /** Explicit type application.
-  */
+   *  @PP: All signs point toward it being a requirement that args.nonEmpty,
+   *  but I can't find that explicitly stated anywhere.  Unless your last name
+   *  is odersky, you should probably treat it as true.
+   */
   case class TypeApply(fun: Tree, args: List[Tree])
        extends GenericApply {
     override def symbol: Symbol = fun.symbol