diff --git a/mie/ctx.c b/mie/ctx.c
index 3ee8487..dd476ab 100644
--- a/mie/ctx.c
+++ b/mie/ctx.c
@@ -231,7 +231,7 @@ const struct mie_trait *mie_ctx_get_trait(
 		return NULL;
 	}
 
-	memset(trait, 0x0, sizeof *trait);
+	memset(trait, 0x0, sizeof trait_info->tr_data_size);
 
 	trait->tr_def = trait_info;
 	trait->tr_name = b_bstr_fmt("%s.%s", dialect_name, trait_name);