Address reviewers comments

Author: odersky

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

@@ -734,7 +734,7 @@ object Denotations {
         this
       case _ =>
         if (coveredInterval.containsPhaseId(ctx.phaseId)) {
-          if (ctx.debug || true) ctx.traceInvalid(this)
+          if (ctx.debug) ctx.traceInvalid(this)
           staleSymbolError
         }
         else NoDenotation

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

@@ -400,13 +400,13 @@ object Flags {
   final val Scala2ModuleVar = termFlag(57, "<modulevar>")
 
   /** A Scala 2.12 trait that has been augmented with static members */
-  final val Scala_2_12_Augmented = typeFlag(57, "<scala12augmented")
+  final val Scala_2_12_Augmented = typeFlag(57, "<scala_2_12_augmented>")
 
   /** A definition that's initialized before the super call (Scala 2.x only) */
   final val Scala2PreSuper = termFlag(58, "<presuper>")
 
   /** A Scala 2.12 or higher trait */
-  final val Scala_2_12_Trait = typeFlag(58, "<scala12trait>")
+  final val Scala_2_12_Trait = typeFlag(58, "<scala_2_12_trait>")
 
   /** A macro (Scala 2.x only) */
   final val Macro = commonFlag(59, "<macro>")