Refine bringForward to work with overloaded symbols

Author: odersky

compiler/src/dotty/tools/dotc/core/Denotations.scala

@@ -789,10 +789,7 @@ object Denotations {
       this match {
         case symd: SymDenotation =>
           if (ctx.stillValid(symd)) return updateValidity()
-          if (ctx.acceptStale(symd)) {
-            val newd = symd.owner.info.decls.lookup(symd.name)
-            return (newd.denot: SingleDenotation).orElse(symd).updateValidity()
-          }
+          if (ctx.acceptStale(symd)) return symd.currentSymbol.denot.orElse(symd).updateValidity()
         case _ =>
       }
       if (!symbol.exists) return updateValidity()

compiler/src/dotty/tools/dotc/core/SymDenotations.scala

@@ -959,7 +959,6 @@ object SymDenotations {
       }
     }
 
-
     /** The class with the same (type-) name as this module or module class,
       *  and which is also defined in the same scope and compilation unit.
       *  NoSymbol if this class does not exist.
@@ -1135,6 +1134,22 @@ object SymDenotations {
     /** The primary constructor of a class or trait, NoSymbol if not applicable. */
     def primaryConstructor(implicit ctx: Context): Symbol = NoSymbol
 
+    /** The current declaration of this symbol's class owner that has the same name
+     *  as this one, and, if there are several, also has the same signature.
+     */
+    def currentSymbol(implicit ctx: Context): Symbol = {
+      val candidates = owner.info.decls.lookupAll(name)
+      def test(sym: Symbol): Symbol =
+        if (sym == symbol || sym.signature == signature) sym
+        else if (candidates.hasNext) test(candidates.next)
+        else NoSymbol
+      if (candidates.hasNext) {
+        val sym = candidates.next
+        if (candidates.hasNext) test(sym) else sym
+      }
+      else NoSymbol
+    }
+
     // ----- type-related ------------------------------------------------
 
     /** The type parameters of a class symbol, Nil for all other symbols */