diff --git a/include/jemalloc/internal/tcache_types.h b/include/jemalloc/internal/tcache_types.h
index a91b3252..578a199e 100644
--- a/include/jemalloc/internal/tcache_types.h
+++ b/include/jemalloc/internal/tcache_types.h
@@ -10,7 +10,7 @@ typedef struct tcaches_s tcaches_t;
 
 /* Used in TSD static initializer only. Real init in tsd_tcache_data_init(). */
 #define TCACHE_ZERO_INITIALIZER {0}
-#define TCACHE_SLOW_ZERO_INITIALIZER {0}
+#define TCACHE_SLOW_ZERO_INITIALIZER {{0}}
 
 /* Used in TSD static initializer only. Will be initialized to opt_tcache. */
 #define TCACHE_ENABLED_ZERO_INITIALIZER false