diff --git a/lang/module.c b/lang/module.c
index 2ed171e..adcb74f 100644
--- a/lang/module.c
+++ b/lang/module.c
@@ -8,6 +8,7 @@
 #include "object.h"
 #include "string.h"
 #include "vm.h"
+#include <stdbool.h>
 
 // Useful macro for getting array size
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
@@ -58,13 +59,13 @@
 }
 
 // Checks if a ModuleInfo is in a module_stack
-static int in_stack(const ModuleInfo *info, struct module_stack *stack) {
+static bool in_stack(const ModuleInfo *info, struct module_stack *stack) {
 	for (int i = 0; i < stack->next; ++i) {
 		const ModuleInfo *elem = stack->elems[i];
 		if (elem == info)
-			return 1;
+			return true;
 	}
-	return 0;
+	return false;
 }
 
 // Traverses a module use dependency tree, checking for circular dependencies