anchor.diff:      : (
           qualifiedType
           { $type=$qualifiedType.type; }
  -        //-> ^(EXTENDED_TYPE[$EXTENDS] type ^(INVOCATION_EXPRESSION ^(EXTENDED_TYPE_EXPRESSION) positionalArguments))
         | SUPER MEMBER_OP 
           typeReference 
           { QualifiedType qt=new QualifiedType(null);
  
positive.code:         defaultCaseBlock
          { $switchCaseList.setElseClause($defaultCaseBlock.clause); }
        )?
      //-> ^(SWITCH_CASE_LIST caseItem+ defaultCaseItem?)
      ;
      
  caseBlock returns [CaseClause clause]
  
negative.code:       SEMICOLON
        { expecting=-1; }
        { $declaration.setEndToken($SEMICOLON); }
      ;
  
  namedArgumentDeclaration returns [NamedArgument declaration]
  