diff --git a/flamingo/grammar/map.h b/flamingo/grammar/map.h
index a61fe01..75fd8fd 100644
--- a/flamingo/grammar/map.h
+++ b/flamingo/grammar/map.h
@@ -62,6 +62,10 @@ static int parse_map(flamingo_t* flamingo, TSNode node, flamingo_val_t** val) {
 		vals[count - 1] = v;
 	}
 
+	if (val == NULL) {
+		return 0;
+	}
+
 	assert(*val == NULL);
 	*val = val_alloc();
 
diff --git a/flamingo/grammar/vec.h b/flamingo/grammar/vec.h
index 687dc1f..3411d42 100644
--- a/flamingo/grammar/vec.h
+++ b/flamingo/grammar/vec.h
@@ -34,6 +34,10 @@ static int parse_vec(flamingo_t* flamingo, TSNode node, flamingo_val_t** val) {
 		elems[elem_count - 1] = elem;
 	}
 
+	if (val == NULL) {
+		return 0;
+	}
+
 	assert(*val == NULL);
 	*val = val_alloc();