Index: libcxx/include/locale
===================================================================
--- libcxx/include/locale
+++ libcxx/include/locale
@@ -2885,6 +2885,10 @@
                                             unique_ptr<char_type, void(*)(void*)>& __wb,
                                             char_type*& __wn, char_type* __we)
 {
+    if (__b == __e) {
+      __err |= ios_base::failbit;
+      return false;
+    }
     const unsigned __bz = 100;
     unsigned __gbuf[__bz];
     unique_ptr<unsigned, void(*)(void*)> __gb(__gbuf, __do_nothing);
Index: libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_en_US.pass.cpp
===================================================================
--- libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_en_US.pass.cpp
+++ libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_en_US.pass.cpp
@@ -721,6 +721,17 @@
             assert(err == std::ios_base::failbit);
         }
     }
+    {
+        // test for err
+        const my_facet f(1);
+        std::string v = "1.23";
+        typedef input_iterator<const char*> I;
+        long double ex = -1L;
+        std::ios_base::iostate err = std::ios_base::goodbit;
+        f.get(I(v.data()), I(v.data()), false, ios, err, ex);
+        assert(err == (std::ios_base::failbit | std::ios_base::eofbit));
+        assert(ex == -1L);
+    }
 
   return 0;
 }
Index: libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_string_en_US.pass.cpp
===================================================================
--- libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_string_en_US.pass.cpp
+++ libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_string_en_US.pass.cpp
@@ -729,6 +729,17 @@
             assert(ex == L"");
         }
     }
+    {
+        // test for err
+        const my_facet f(1);
+        std::string v = "1.23";
+        typedef input_iterator<const char*> I;
+        std::string ex = "NULL";
+        std::ios_base::iostate err = std::ios_base::goodbit;
+        f.get(I(v.data()), I(v.data()), false, ios, err, ex);
+        assert(err == (std::ios_base::failbit | std::ios_base::eofbit));
+        assert(ex == "NULL");
+    }
 
   return 0;
 }
Index: libcxx/utils/libcxx/test/params.py
===================================================================
--- libcxx/utils/libcxx/test/params.py
+++ libcxx/utils/libcxx/test/params.py
@@ -9,32 +9,32 @@
 from libcxx.test.dsl import *
 
 _warningFlags = [
-  '-Werror',
-  '-Wall',
-  '-Wextra',
-  '-Wshadow',
-  '-Wundef',
-  '-Wno-unused-command-line-argument',
-  '-Wno-attributes',
-  '-Wno-pessimizing-move',
-  '-Wno-c++11-extensions',
-  '-Wno-user-defined-literals',
-  '-Wno-noexcept-type',
-  '-Wno-aligned-allocation-unavailable',
-  '-Wno-atomic-alignment',
+  #'-Werror',
+  #'-Wall',
+  #'-Wextra',
+  #'-Wshadow',
+  #'-Wundef',
+  #'-Wno-unused-command-line-argument',
+  #'-Wno-attributes',
+  #'-Wno-pessimizing-move',
+  #'-Wno-c++11-extensions',
+  #'-Wno-user-defined-literals',
+  #'-Wno-noexcept-type',
+  #'-Wno-aligned-allocation-unavailable',
+  #'-Wno-atomic-alignment',
 
-  # GCC warns about places where we might want to add sized allocation/deallocation
-  # functions, but we know better what we're doing/testing in the test suite.
-  '-Wno-sized-deallocation',
+  ## GCC warns about places where we might want to add sized allocation/deallocation
+  ## functions, but we know better what we're doing/testing in the test suite.
+  #'-Wno-sized-deallocation',
 
-  # These warnings should be enabled in order to support the MSVC
-  # team using the test suite; They enable the warnings below and
-  # expect the test suite to be clean.
-  '-Wsign-compare',
-  '-Wunused-variable',
-  '-Wunused-parameter',
-  '-Wunreachable-code',
-  '-Wno-unused-local-typedef',
+  ## These warnings should be enabled in order to support the MSVC
+  ## team using the test suite; They enable the warnings below and
+  ## expect the test suite to be clean.
+  #'-Wsign-compare',
+  #'-Wunused-variable',
+  #'-Wunused-parameter',
+  #'-Wunreachable-code',
+  #'-Wno-unused-local-typedef',
 ]
 
 _allStandards = ['c++03', 'c++11', 'c++14', 'c++17', 'c++20', 'c++2b']