diff --git a/base/untyped/lit.go b/base/untyped/lit.go
index d8e5415a..86fea452 100644
--- a/base/untyped/lit.go
+++ b/base/untyped/lit.go
@@ -128,7 +128,7 @@ again:
 
 			i, exact := constant.Int64Val(val)
 			if exact {
-				ret = string(i)
+				ret = string(rune(i))
 			} else {
 				ret = "\uFFFD"
 			}