diff --git a/src/value.c b/src/value.c
index f30963d..10d4a1f 100644
--- a/src/value.c
+++ b/src/value.c
@@ -856,7 +856,9 @@ apfl_gc_func_traverse(struct function* function, gc_visitor cb, void *opaque)
             cb(opaque, GC_OBJECT_FROM(sub->matcher, GC_TYPE_MATCHER));
         }
     }
-    cb(opaque, GC_OBJECT_FROM(function->scope, GC_TYPE_SCOPE));
+    if (function->scope != NULL) {
+        cb(opaque, GC_OBJECT_FROM(function->scope, GC_TYPE_SCOPE));
+    }
     if (function->name != NULL) {
         cb(opaque, GC_OBJECT_FROM(function->name, GC_TYPE_STRING));
     }
diff --git a/src/value.h b/src/value.h
index 281c8e4..47a825e 100644
--- a/src/value.h
+++ b/src/value.h
@@ -51,7 +51,7 @@ struct function {
     struct subfunction *subfunctions;
     size_t subfunctions_len;
     size_t subfunctions_cap;
-    struct scope *scope;
+    struct scope *scope; // Can be NULL
     struct apfl_string *name;
     int line_defined;
     struct apfl_string *filename;
@@ -148,7 +148,7 @@ void apfl_dict_deinit(struct dict_header *);
 struct function *apfl_func_new(
     struct gc *,
     size_t cap,
-    struct scope *,
+    struct scope *, // Can be NULL
     int line_defined,
     struct apfl_string *filename
 );