Set the scene for Sammy.

Go beyond refactoring and introduce some hooks and patch some
holes that will become acute when we set Sammy loose.

Expanding sam requires class as first parent: `addObjectParent`.
(Tested in pos/sam_ctor_arg.scala, coming next.)

2 files changed, 23 insertions, 0 deletions

diff --git a/src/reflect/scala/reflect/internal/Definitions.scala b/src/reflect/scala/reflect/internal/Definitions.scala
index 9a212fcbcb..2fa39bc453 100644
--- a/src/reflect/scala/reflect/internal/Definitions.scala
+++ b/src/reflect/scala/reflect/internal/Definitions.scala
@@ -686,11 +686,29 @@ trait Definitions extends api.StandardDefinitions {
       }
     }
 
+    // the result type of a function or corresponding SAM type
+    def functionResultType(tp: Type): Type = {
+      val dealiased = tp.dealiasWiden
+      if (isFunctionTypeDirect(dealiased)) dealiased.typeArgs.last
+      else samOf(tp) match {
+        case samSym if samSym.exists => tp.memberInfo(samSym).resultType.deconst
+        case _ => NoType
+      }
+    }
+
     // the SAM's parameters and the Function's formals must have the same length
     // (varargs etc don't come into play, as we're comparing signatures, not checking an application)
     def samMatchesFunctionBasedOnArity(sam: Symbol, formals: List[Any]): Boolean =
       sam.exists && sameLength(sam.info.params, formals)
 
+    def samMatchingFunction(tree: Tree, pt: Type): Symbol = {
+      if (tree.isInstanceOf[Function] && !isFunctionType(pt)) {
+        val sam = samOf(pt)
+        if (samMatchesFunctionBasedOnArity(sam, tree.asInstanceOf[Function].vparams)) sam
+        else NoSymbol
+      } else NoSymbol
+    }
+
     def isTupleType(tp: Type)          = isTupleTypeDirect(tp.dealiasWiden)
     def tupleComponents(tp: Type)      = tp.dealiasWiden.typeArgs
 
diff --git a/src/reflect/scala/reflect/internal/Types.scala b/src/reflect/scala/reflect/internal/Types.scala
index f385ca08c9..00df55f044 100644
--- a/src/reflect/scala/reflect/internal/Types.scala
+++ b/src/reflect/scala/reflect/internal/Types.scala
@@ -4553,6 +4553,11 @@ trait Types
     else (ps :+ SerializableTpe).toList
   )
 
+  def addObjectParent(tps: List[Type]) = tps match {
+    case hd :: _ if hd.typeSymbol.isTrait => ObjectTpe :: tps
+    case _ => tps
+  }
+
   /** Adds the @uncheckedBound annotation if the given `tp` has type arguments */
   final def uncheckedBounds(tp: Type): Type = {
     if (tp.typeArgs.isEmpty || UncheckedBoundsClass == NoSymbol) tp // second condition for backwards compatibility with older scala-reflect.jar