diff --git a/src/nspawn/nspawn-settings.h b/src/nspawn/nspawn-settings.h
index c786bf8c86..4e9cf3e315 100644
--- a/src/nspawn/nspawn-settings.h
+++ b/src/nspawn/nspawn-settings.h
@@ -56,9 +56,19 @@ typedef enum SettingsMask {
         SETTING_CPU_AFFINITY      = UINT64_C(1) << 20,
         SETTING_RLIMIT_FIRST      = UINT64_C(1) << 21, /* we define one bit per resource limit here */
         SETTING_RLIMIT_LAST       = UINT64_C(1) << (21 + _RLIMIT_MAX - 1),
-        _SETTINGS_MASK_ALL        = (UINT64_C(1) << (21 + _RLIMIT_MAX)) - 1
+        _SETTINGS_MASK_ALL        = (UINT64_C(1) << (21 + _RLIMIT_MAX)) - 1,
+        _FORCE_ENUM_WIDTH         = UINT64_MAX
 } SettingsMask;
 
+/* We want to use SETTING_RLIMIT_FIRST in shifts, so make sure it is really 64 bits
+ * when used in expressions. */
+#define SETTING_RLIMIT_FIRST ((uint64_t) SETTING_RLIMIT_FIRST)
+#define SETTING_RLIMIT_LAST ((uint64_t) SETTING_RLIMIT_LAST)
+
+assert_cc(sizeof(SettingsMask) == 8);
+assert_cc(sizeof(SETTING_RLIMIT_FIRST) == 8);
+assert_cc(sizeof(SETTING_RLIMIT_LAST) == 8);
+
 typedef struct Settings {
         /* [Run] */
         StartMode start_mode;
diff --git a/src/systemd/sd-resolve.h b/src/systemd/sd-resolve.h
index 14d0cbde04..d4921e9559 100644
--- a/src/systemd/sd-resolve.h
+++ b/src/systemd/sd-resolve.h
@@ -43,9 +43,9 @@ typedef int (*sd_resolve_getaddrinfo_handler_t)(sd_resolve_query *q, int ret, co
 typedef int (*sd_resolve_getnameinfo_handler_t)(sd_resolve_query *q, int ret, const char *host, const char *serv, void *userdata);
 
 enum {
-        SD_RESOLVE_GET_HOST = UINT64_C(1),
-        SD_RESOLVE_GET_SERVICE = UINT64_C(2),
-        SD_RESOLVE_GET_BOTH = UINT64_C(3),
+        SD_RESOLVE_GET_HOST    = 1 << 0,
+        SD_RESOLVE_GET_SERVICE = 1 << 1,
+        SD_RESOLVE_GET_BOTH = SD_RESOLVE_GET_HOST | SD_RESOLVE_GET_SERVICE,
 };
 
 int sd_resolve_default(sd_resolve **ret);
diff --git a/src/test/test-sizeof.c b/src/test/test-sizeof.c
index 2ebbbb304a..d7897ed765 100644
--- a/src/test/test-sizeof.c
+++ b/src/test/test-sizeof.c
@@ -26,7 +26,12 @@ enum Enum {
 };
 
 enum BigEnum {
-        big_enum_value = UINT64_C(-1),
+        big_enum_value = UINT64_C(1),
+};
+
+enum BigEnum2 {
+        big_enum2_pos = UINT64_C(1),
+        big_enum2_neg = UINT64_C(-1),
 };
 
 int main(void) {
@@ -55,6 +60,10 @@ int main(void) {
 
         info(enum Enum);
         info(enum BigEnum);
+        info(enum BigEnum2);
+        assert_cc(sizeof(enum BigEnum2) == 8);
+        printf("big_enum2_pos → %zu\n", sizeof(big_enum2_pos));
+        printf("big_enum2_neg → %zu\n", sizeof(big_enum2_neg));
 
         return 0;
 }