diff --git a/src/basic/locale-util.c b/src/basic/locale-util.c
index 93261e675e..b818078158 100644
--- a/src/basic/locale-util.c
+++ b/src/basic/locale-util.c
@@ -427,8 +427,10 @@ const char *special_glyph(SpecialGlyph code) {
                 },
         };
 
-        assert(code < _SPECIAL_GLYPH_MAX);
+        if (code < 0)
+                return NULL;
 
+        assert(code < _SPECIAL_GLYPH_MAX);
         return draw_table[code >= _SPECIAL_GLYPH_FIRST_EMOJI ? emoji_enabled() : is_locale_utf8()][code];
 }
 
diff --git a/src/basic/locale-util.h b/src/basic/locale-util.h
index 558c5a898b..df259d1bbd 100644
--- a/src/basic/locale-util.h
+++ b/src/basic/locale-util.h
@@ -39,7 +39,7 @@ void init_gettext(void);
 
 bool is_locale_utf8(void);
 
-typedef enum {
+typedef enum SpecialGlyph {
         SPECIAL_GLYPH_TREE_VERTICAL,
         SPECIAL_GLYPH_TREE_BRANCH,
         SPECIAL_GLYPH_TREE_RIGHT,
@@ -70,6 +70,7 @@ typedef enum {
         SPECIAL_GLYPH_LOCK_AND_KEY,
         SPECIAL_GLYPH_TOUCH,
         _SPECIAL_GLYPH_MAX,
+        _SPECIAL_GLYPH_INVALID = -EINVAL,
 } SpecialGlyph;
 
 const char *special_glyph(SpecialGlyph code) _const_;
diff --git a/src/basic/unit-def.c b/src/basic/unit-def.c
index 6fbb947f09..5cfabca83f 100644
--- a/src/basic/unit-def.c
+++ b/src/basic/unit-def.c
@@ -296,22 +296,19 @@ static const char* const notify_access_table[_NOTIFY_ACCESS_MAX] = {
 DEFINE_STRING_TABLE_LOOKUP(notify_access, NotifyAccess);
 
 SpecialGlyph unit_active_state_to_glyph(UnitActiveState state) {
-        switch (state) {
-                case UNIT_ACTIVE:
-                    return SPECIAL_GLYPH_BLACK_CIRCLE;
-                case UNIT_RELOADING:
-                    return SPECIAL_GLYPH_CIRCLE_ARROW;
-                case UNIT_INACTIVE:
-                    return SPECIAL_GLYPH_WHITE_CIRCLE;
-                case UNIT_FAILED:
-                    return SPECIAL_GLYPH_MULTIPLICATION_SIGN;
-                case UNIT_ACTIVATING:
-                case UNIT_DEACTIVATING:
-                    return SPECIAL_GLYPH_BLACK_CIRCLE;
-                case UNIT_MAINTENANCE:
-                    return SPECIAL_GLYPH_WHITE_CIRCLE;
+        static const SpecialGlyph map[_UNIT_ACTIVE_STATE_MAX] = {
+                [UNIT_ACTIVE]       = SPECIAL_GLYPH_BLACK_CIRCLE,
+                [UNIT_RELOADING]    = SPECIAL_GLYPH_CIRCLE_ARROW,
+                [UNIT_INACTIVE]     = SPECIAL_GLYPH_WHITE_CIRCLE,
+                [UNIT_FAILED]       = SPECIAL_GLYPH_MULTIPLICATION_SIGN,
+                [UNIT_ACTIVATING]   = SPECIAL_GLYPH_BLACK_CIRCLE,
+                [UNIT_DEACTIVATING] = SPECIAL_GLYPH_BLACK_CIRCLE,
+                [UNIT_MAINTENANCE]  = SPECIAL_GLYPH_WHITE_CIRCLE,
+        };
 
-                default:
-                    return SPECIAL_GLYPH_BLACK_CIRCLE;
-            }
+        if (state < 0)
+                return _SPECIAL_GLYPH_INVALID;
+
+        assert(state < _UNIT_ACTIVE_STATE_MAX);
+        return map[state];
 }