anchor.diff:      DO_BLOCK;
       DO_ITERATOR;
       EXPR;
  +    EXPR_LIST;
  +    EXPR_STMT;
       FINALLY_BLOCK;
       FORMAL_PARAMETER;
       FORMAL_PARAMETER_LIST;
  
positive.code: 
  compilationUnit
      : importDeclaration*
        declaration+
        EOF
      -> ^(IMPORT_LIST importDeclaration*)
         declaration+
      ;
  
  typeDeclaration
  
negative.code:     ;
  
  variance
      : 'in' -> IN 
      | 'out' -> OUT
      ;
      
  dimensionalTypeParameter
  