diff --git a/jim.h b/jim.h
index 12f38f0..e0a227a 100644
--- a/jim.h
+++ b/jim.h
@@ -25,9 +25,9 @@ typedef enum {
 } Jim_Scope_Kind;
 
 typedef struct {
-    Jim_Scope_Kind kind;
-    int tail;
-    int key;
+    unsigned char kind : 6;
+    unsigned char tail : 1;
+    unsigned char key : 1;
 } Jim_Scope;
 
 typedef struct {
diff --git a/test.c b/test.c
index f25fe59..16f782d 100644
--- a/test.c
+++ b/test.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <assert.h>
 
 #define JIM_IMPLEMENTATION
 #include "./jim.h"
@@ -202,6 +203,8 @@ void test(void)
 
 int main(int argc, char **argv)
 {
+    assert(sizeof(Jim_Scope) == 1);
+
     if (argc >= 2) {
         if (strcmp(argv[1], "record") == 0) {
             record("test_expected.h");