Fix Scope.exists

Author: nicolasstucki

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

@@ -106,7 +106,7 @@ object Scopes {
     }
 
     /** Tests whether a predicate holds for at least one Symbol of this Scope. */
-    def exists(p: Symbol => Boolean)(implicit ctx: Context): Boolean = filter(p).isEmpty
+    def exists(p: Symbol => Boolean)(implicit ctx: Context): Boolean = filter(p).nonEmpty
 
     /** Finds the first Symbol of this Scope satisfying a predicate, if any. */
     def find(p: Symbol => Boolean)(implicit ctx: Context): Symbol = filter(p) match {

compiler/src/dotty/tools/dotc/transform/YCheckPositions.scala

@@ -58,7 +58,7 @@ class YCheckPositions extends Phases.Phase {
 
   private def isMacro(call: Tree)(implicit ctx: Context) = {
     if (ctx.phase <= ctx.typerPhase.next) call.symbol.is(Macro)
-    else (call.symbol.unforcedDecls.exists(_.is(Macro)) || call.symbol.unforcedDecls.toList.exists(_.is(Macro)))
+    else (call.symbol.unforcedDecls.isEmpty /* bug from exists */ || call.symbol.unforcedDecls.exists(_.is(Macro)) || call.symbol.unforcedDecls.toList.exists(_.is(Macro)))
   }
 
 }