diff --git a/src/cmd/gc/fmt.c b/src/cmd/gc/fmt.c
index ee5b9e939b..8a14aa2df9 100644
--- a/src/cmd/gc/fmt.c
+++ b/src/cmd/gc/fmt.c
@@ -630,7 +630,7 @@ typefmt(Fmt *fp, Type *t)
 
 	case TARRAY:
 		if(t->bound >= 0)
-			return fmtprint(fp, "[%d]%T", (int)t->bound, t->type);
+			return fmtprint(fp, "[%lld]%T", t->bound, t->type);
 		if(t->bound == -100)
 			return fmtprint(fp, "[...]%T", t->type);
 		return fmtprint(fp, "[]%T", t->type);