diff --git a/include/fmt/format.h b/include/fmt/format.h
index 464c0d72..98c15c64 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -2501,7 +2501,7 @@ FMT_CONSTEXPR const Char* parse_align(const Char* begin, const Char* end,
   auto p = next_code_point(begin, end);
   if (p == end) p = begin;
   for (;;) {
-    switch (static_cast<char>(*p)) {
+    switch (static_cast<int>(*p)) {
     case '<':
       align = align::left;
       break;
diff --git a/test/format-test.cc b/test/format-test.cc
index 7841c68f..2d017a81 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1525,6 +1525,7 @@ TEST(FormatterTest, WideFormatString) {
   EXPECT_EQ(L"4.2", format(L"{}", 4.2));
   EXPECT_EQ(L"abc", format(L"{}", L"abc"));
   EXPECT_EQ(L"z", format(L"{}", L'z'));
+  EXPECT_THROW(fmt::format(L"{:*\x343E}", 42), fmt::format_error);
 }
 
 TEST(FormatterTest, FormatStringFromSpeedTest) {