Merge pull request #5307 from adriaanm/issue-157

Propagate overloaded function type to expected arg type

2 files changed, 17 insertions, 0 deletions

diff --git a/src/reflect/scala/reflect/internal/Definitions.scala b/src/reflect/scala/reflect/internal/Definitions.scala
index 5025c1fa6d..d0539dfd42 100644
--- a/src/reflect/scala/reflect/internal/Definitions.scala
+++ b/src/reflect/scala/reflect/internal/Definitions.scala
@@ -687,6 +687,17 @@ trait Definitions extends api.StandardDefinitions {
       }
     }
 
+    // the argument types expected by the function described by `tp` (a FunctionN or SAM type),
+    // or `Nil` if `tp` does not represent a function type or SAM (or if it happens to be Function0...)
+    def functionOrSamArgTypes(tp: Type): List[Type] = {
+      val dealiased = tp.dealiasWiden
+      if (isFunctionTypeDirect(dealiased)) dealiased.typeArgs.init
+      else samOf(tp) match {
+        case samSym if samSym.exists => tp.memberInfo(samSym).paramTypes
+        case _ => Nil
+      }
+    }
+
     // 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 =
diff --git a/src/reflect/scala/reflect/internal/TreeInfo.scala b/src/reflect/scala/reflect/internal/TreeInfo.scala
index 86b70643c9..b9f3e987ee 100644
--- a/src/reflect/scala/reflect/internal/TreeInfo.scala
+++ b/src/reflect/scala/reflect/internal/TreeInfo.scala
@@ -263,6 +263,12 @@ abstract class TreeInfo {
     true
   }
 
+  def isFunctionMissingParamType(tree: Tree): Boolean = tree match {
+    case Function(vparams, _) => vparams.exists(_.tpt.isEmpty)
+    case _ => false
+  }
+
+
   /** Is symbol potentially a getter of a variable?
    */
   def mayBeVarGetter(sym: Symbol): Boolean = sym.info match {