diff --git a/libcxx/.clang-tidy b/libcxx/.clang-tidy
--- a/libcxx/.clang-tidy
+++ b/libcxx/.clang-tidy
@@ -10,6 +10,7 @@
 
   -misc-unconventional-assign-operator,
 
+  modernize-loop-convert,
   modernize-redundant-void-arg,
 
   readability-duplicate-include,
@@ -33,7 +34,6 @@
 # bugprone-branch-clone,
 # bugprone-macro-parentheses,
 # cppcoreguidelines-prefer-member-initializer,
-# modernize-loop-convert,
 # modernize-use-bool-literals,
 # modernize-use-default-member-init,
 # modernize-use-equals-default,
diff --git a/libcxx/include/locale b/libcxx/include/locale
--- a/libcxx/include/locale
+++ b/libcxx/include/locale
@@ -3221,9 +3221,9 @@
                               int __fd)
 {
     __me = __mb;
-    for (unsigned __p = 0; __p < 4; ++__p)
+    for (char __p : __pat.field)
     {
-        switch (__pat.field[__p])
+        switch (__p)
         {
         case money_base::none:
             __mi = __me;