diff --git a/src/basic/env-util.h b/src/basic/env-util.h
index 4d21ea6bef..d54f99658b 100644
--- a/src/basic/env-util.h
+++ b/src/basic/env-util.h
@@ -13,9 +13,9 @@ bool env_value_is_valid(const char *e);
 bool env_assignment_is_valid(const char *e);
 
 enum {
-        REPLACE_ENV_USE_ENVIRONMENT = 1u,
-        REPLACE_ENV_ALLOW_BRACELESS = 2u,
-        REPLACE_ENV_ALLOW_EXTENDED  = 4u,
+        REPLACE_ENV_USE_ENVIRONMENT = 1 << 0,
+        REPLACE_ENV_ALLOW_BRACELESS = 1 << 1,
+        REPLACE_ENV_ALLOW_EXTENDED  = 1 << 2,
 };
 
 char *replace_env_n(const char *format, size_t n, char **env, unsigned flags);