diff --git a/test/std/input.output/iostream.format/ext.manip/put_money.pass.cpp b/test/std/input.output/iostream.format/ext.manip/put_money.pass.cpp
index 66be9f0..342e337 100644
--- a/test/std/input.output/iostream.format/ext.manip/put_money.pass.cpp
+++ b/test/std/input.output/iostream.format/ext.manip/put_money.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = str_.size();
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/ext.manip/put_time.pass.cpp b/test/std/input.output/iostream.format/ext.manip/put_time.pass.cpp
index d12b91c..dae74f0 100644
--- a/test/std/input.output/iostream.format/ext.manip/put_time.pass.cpp
+++ b/test/std/input.output/iostream.format/ext.manip/put_time.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/streambuf.pass.cpp b/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/streambuf.pass.cpp
index a599d4d..6b6737a 100644
--- a/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/streambuf.pass.cpp
+++ b/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/streambuf.pass.cpp
@@ -41,18 +41,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = str_.size();
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf.pass.cpp b/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf.pass.cpp
index e732729..0a48393 100644
--- a/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf.pass.cpp
+++ b/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf.pass.cpp
@@ -38,18 +38,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf_chart.pass.cpp b/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf_chart.pass.cpp
index 292cf7c..c6368b4 100644
--- a/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf_chart.pass.cpp
+++ b/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf_chart.pass.cpp
@@ -39,18 +39,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/bool.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/bool.pass.cpp
index fe038a7..00332f7 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/bool.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/bool.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/double.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/double.pass.cpp
index 197e460..1ee2c56 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/double.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/double.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/float.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/float.pass.cpp
index d31da5a..db64b66 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/float.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/float.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/int.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/int.pass.cpp
index 1b33280..5e601a9 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/int.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/int.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long.pass.cpp
index 7cf4609..125c080 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_double.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_double.pass.cpp
index dba3f8a..4b235f4 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_double.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_double.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_long.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_long.pass.cpp
index 1174a09..44b189d 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_long.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_long.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/pointer.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/pointer.pass.cpp
index f658939..a8bdaba 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/pointer.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/pointer.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/short.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/short.pass.cpp
index 3b8182c..06b6e5c 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/short.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/short.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_int.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_int.pass.cpp
index 61057f7..e6070ef 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_int.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_int.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long.pass.cpp
index 4558993..7f8cf46 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long_long.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long_long.pass.cpp
index 1727b36..59be66f 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long_long.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long_long.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_short.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_short.pass.cpp
index a42cd56..6508f2d 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_short.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_short.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT.pass.cpp
index b778da2..26bfd89 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(__c);
+                str_.push_back(ch);
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT_pointer.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT_pointer.pass.cpp
index 29153c1..1f05684 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT_pointer.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT_pointer.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(__c);
+                str_.push_back(ch);
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char.pass.cpp
index 91ee08c..0fe2c35 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_pointer.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_pointer.pass.cpp
index 1eb48d3..f5e8ad4 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_pointer.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_pointer.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide.pass.cpp
index a50e376..09784c0 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(__c);
+                str_.push_back(ch);
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide_pointer.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide_pointer.pass.cpp
index 5c900e6..2e40cf4 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide_pointer.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide_pointer.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(__c);
+                str_.push_back(ch);
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char.pass.cpp
index d57d0e7..8ed0bfb 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char_pointer.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char_pointer.pass.cpp
index e51e881..e3ff047 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char_pointer.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char_pointer.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char.pass.cpp
index 9956f3b..32c044d 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char_pointer.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char_pointer.pass.cpp
index d87e733..199c5df 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char_pointer.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char_pointer.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp
index ef7e292..9d45af0 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ios_base.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ios_base.pass.cpp
index 933e01c..21260d3 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ios_base.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ios_base.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ostream.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ostream.pass.cpp
index 5c0604b..d4516d2 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ostream.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ostream.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/streambuf.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/streambuf.pass.cpp
index a26450a..e510825 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/streambuf.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/streambuf.pass.cpp
@@ -41,18 +41,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.manip/endl.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.manip/endl.pass.cpp
index 72df608..9e8a5c8 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.manip/endl.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.manip/endl.pass.cpp
@@ -37,18 +37,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 
     virtual int
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.manip/ends.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.manip/ends.pass.cpp
index dcded34..f372701 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.manip/ends.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.manip/ends.pass.cpp
@@ -35,18 +35,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.rvalue/CharT_pointer.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.rvalue/CharT_pointer.pass.cpp
index 83210c0..f04d468 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.rvalue/CharT_pointer.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.rvalue/CharT_pointer.pass.cpp
@@ -39,18 +39,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.unformatted/put.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.unformatted/put.pass.cpp
index 0958f83..87a94ed 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.unformatted/put.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.unformatted/put.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };
 
diff --git a/test/std/input.output/iostream.format/output.streams/ostream.unformatted/write.pass.cpp b/test/std/input.output/iostream.format/output.streams/ostream.unformatted/write.pass.cpp
index 0d6eb3f..71f9ad6 100644
--- a/test/std/input.output/iostream.format/output.streams/ostream.unformatted/write.pass.cpp
+++ b/test/std/input.output/iostream.format/output.streams/ostream.unformatted/write.pass.cpp
@@ -34,18 +34,18 @@
 protected:
 
     virtual typename base::int_type
-        overflow(typename base::int_type __c = base::traits_type::eof())
+        overflow(typename base::int_type ch = base::traits_type::eof())
         {
-            if (__c != base::traits_type::eof())
+            if (ch != base::traits_type::eof())
             {
                 int n = static_cast<int>(str_.size());
-                str_.push_back(static_cast<CharT>(__c));
+                str_.push_back(static_cast<CharT>(ch));
                 str_.resize(str_.capacity());
                 base::setp(const_cast<CharT*>(str_.data()),
                            const_cast<CharT*>(str_.data() + str_.size()));
                 base::pbump(n+1);
             }
-            return __c;
+            return ch;
         }
 };