anchor.diff:      ;
   
   joinStatement
  -    :   secondLevelId EQUALS secondLevelId
  +    :   secondLevelId EQUAL secondLevelId
       ;
   
   secondLevelId returns [SecondLevelId result]
  
positive.code:     |   FALSE {
          $result = BooleanLiteral.FalseBooleanLiteral.getInstance();
      }
      ;
  
  OR
  
negative.code: 
  import java.util.*;
  import queries.*;
  import expressions.bool.*;
  import expressions.comparison.*;
  }
  
  @members {
  