Fix exception in super resolution

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/init/Checking.scala

@@ -278,7 +278,7 @@ object Checking {
               val target = resolveSuper(cls, supercls, sym)
               if (!target.is(Flags.Method))
                 check(FieldAccess(pot, target)(eff.source))
-              if (target.isInternal) {
+              else if (target.isInternal) {
                 val effs = thisRef.effectsOf(target)
                 effs.foreach { check(_) }
               }

compiler/src/dotty/tools/dotc/transform/init/Util.scala

@@ -7,6 +7,7 @@ import Contexts.Context
 import Symbols._
 import config.Printers.Printer
 
+import annotation.tailrec
 
 object Util {
   def traceIndented(msg: String, printer: Printer)(implicit ctx: Context): Unit =
@@ -25,6 +26,16 @@ object Util {
     if (sym.isEffectivelyFinal || sym.isConstructor) sym
     else sym.matchingMember(cls.typeRef)
 
-  def resolveSuper(cls: ClassSymbol, superCls: ClassSymbol, sym: Symbol)(implicit ctx: Context): Symbol =
-    sym.superSymbolIn(cls)
+  def resolveSuper(cls: ClassSymbol, superCls: ClassSymbol, sym: Symbol)(implicit ctx: Context): Symbol = {
+    // println(s"bases of $cls: " + cls.info.baseClasses)
+    @tailrec def loop(bcs: List[ClassSymbol]): Symbol = bcs match {
+      case bc :: bcs1 =>
+        val cand = sym.matchingDecl(bcs.head, cls.thisType)
+          .suchThat(alt => !alt.is(Flags.Deferred)).symbol
+        if (cand.exists) cand else loop(bcs.tail)
+      case _ =>
+        NoSymbol
+    }
+    loop(cls.info.baseClasses.dropWhile(sym.owner != _))
+  }
 }

tests/init/pos/super1.scala

@@ -0,0 +1,16 @@
+import scala.collection.mutable
+
+class Foo {
+  private val map: mutable.Map[Int, String] = mutable.Map.empty
+
+  def enter(k: Int, v: String) = map(k) = v
+}
+
+class Bar extends Foo {
+  override def enter(k: Int, v: String) = ???
+  def enterSuper(k: Int, v: String) = super.enter(k, v)
+
+  enter(1, "one")
+  enterSuper(1, "one")
+  super.enter(2, "two")
+}