Fix flags of export forwarders

Author: odersky

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

@@ -531,7 +531,7 @@ object Flags {
   val RetainedModuleClassFlags: FlagSet = RetainedModuleValAndClassFlags | Enum
 
   /** Flags retained in export forwarders */
-  val RetainedExportFlags = Given | Implicit | Inline | Transparent | HasDefaultParams | NoDefaultParams
+  val RetainedExportFlags = Given | Implicit | Inline | Transparent
 
   /** Flags that apply only to classes */
   val ClassOnlyFlags = Sealed | Open | Abstract.toTypeFlags

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

@@ -930,7 +930,7 @@ object SymDenotations {
     def hasDefaultParams(using Context): Boolean =
       if ctx.erasedTypes then false
       else if is(HasDefaultParams) then true
-      else if is(NoDefaultParams) then false
+      else if is(NoDefaultParams) || !is(Method) then false
       else
         val result =
           rawParamss.nestedExists(_.is(HasDefault))

compiler/src/dotty/tools/dotc/typer/Namer.scala

@@ -1128,7 +1128,9 @@ class Namer { typer: Typer =>
                   (StableRealizable, ExprType(path.tpe.select(sym)))
                 else
                   (EmptyFlags, mbr.info.ensureMethodic)
-              var mbrFlags = Exported | Method | Final | maybeStable | sym.flags & RetainedExportFlags
+              var flagMask = RetainedExportFlags
+              if sym.isTerm then flagMask |= HasDefaultParams | NoDefaultParams
+              var mbrFlags = Exported | Method | Final | maybeStable | sym.flags & flagMask
               if sym.is(ExtensionMethod) then mbrFlags |= ExtensionMethod
               val forwarderName = checkNoConflict(alias, isPrivate = false, span)
               newSymbol(cls, forwarderName, mbrFlags, mbrInfo, coord = span)