fix: strdup a la con

src/utils/ast/ast_word.c

@@ -2,7 +2,6 @@
 #include "ast_word.h"
 
 #include <stdbool.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -43,6 +42,8 @@ void ast_free_word(struct ast_word *ast_node)
     if (ast_node == NULL)
         return;
 
-    free(ast_node->word);
+    if (ast_node->word != NULL)
+        free(ast_node->word);
+
     free(ast_node);
 }