diff --git a/core/fxcrt/code_point_view.cpp b/core/fxcrt/code_point_view.cpp
index 417e1d0..12b3783 100644
--- a/core/fxcrt/code_point_view.cpp
+++ b/core/fxcrt/code_point_view.cpp
@@ -25,7 +25,7 @@
   if (current_.IsEmpty()) {
     return kSentinel;
   }
-  char32_t code_point = current_.Front();
+  uint32_t code_point = current_.Front();
   next_ = current_.Substr(1);
   if (IsHighSurrogate(code_point)) {
     if (!next_.IsEmpty() && IsLowSurrogate(next_.Front())) {