diff --git a/include/common/trace.h b/include/common/trace.h
index 187ba90..a0918bb 100644
--- a/include/common/trace.h
+++ b/include/common/trace.h
@@ -16,6 +16,6 @@
 
 #define trace_error(state, fmt, ...)            \
     printf("fatal: " fmt, ##__VA_ARGS__);       \
-    printf("near line %d\n", (state)->line_num);
+    printf("near line %zu\n", (state)->line_num);
 
 #endif  /* !COMMON_TRACE_H */