anchor.diff:        { $compilationUnit.setImportList($importList.importList); }
         ( 
           ca2=compilerAnnotations declaration
  -        { $compilationUnit.addDeclaration($declaration.declaration); 
  +        { if ($declaration.declaration!=null)
  +              $compilationUnit.addDeclaration($declaration.declaration); 
             if ($declaration.declaration!=null)
                 $declaration.declaration.getCompilerAnnotations().addAll($ca2.annotations); } 
  -      )+
  +      )*
         EOF
       ;
   
  
positive.code:         |    ('*' ~'/') => '*'
          |    MULTI_COMMENT
          )*
          '*/'
          {
              $channel = HIDDEN;
          }
  
negative.code:     ;
  
  STRING_LITERAL
      :   '"' StringPart '"'?
      ;
  
  fragment
  