[committed] libstdc++: Fix some warnings in headers

[Jonathan Wakely via Gcc-patches]

These are usually suppressed in system headers, but should be fixed
anyway.

libstdc++-v3/ChangeLog:

        * include/bits/parse_numbers.h (_Select_int_base): Avoid
        narrowing conversion in constant expression.
        * include/experimental/buffer (buffer_copy): Avoid narrowing
        conversion.
        * include/experimental/internet (hash<>::operator()): Do not
        use deprecated 'argument_type' member.
        * include/std/variant (variant::emplace): Use cast instead
        of implicit conversion from size_t to narrower unsigned type.

Tested powerpc64le-linux. Committed to trunk.


commit d7aa21a3c78874743a42ffc1af3493ecb665496f
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Thu Oct 29 22:47:22 2020

    libstdc++: Fix some warnings in headers
    
    These are usually suppressed in system headers, but should be fixed
    anyway.
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/parse_numbers.h (_Select_int_base): Avoid
            narrowing conversion in constant expression.
            * include/experimental/buffer (buffer_copy): Avoid narrowing
            conversion.
            * include/experimental/internet (hash<>::operator()): Do not
            use deprecated 'argument_type' member.
            * include/std/variant (variant::emplace): Use cast instead
            of implicit conversion from size_t to narrower unsigned type.

diff --git a/libstdc++-v3/include/bits/parse_numbers.h 
b/libstdc++-v3/include/bits/parse_numbers.h
index 5e80907af09..923a56c5a9f 100644
--- a/libstdc++-v3/include/bits/parse_numbers.h
+++ b/libstdc++-v3/include/bits/parse_numbers.h
@@ -266,7 +266,7 @@ namespace __select_int
   template<unsigned long long _Val, typename _IntType, typename... _Ints>
     struct _Select_int_base<_Val, _IntType, _Ints...>
     : conditional_t<(_Val <= __gnu_cxx::__int_traits<_IntType>::__max),
-                   integral_constant<_IntType, _Val>,
+                   integral_constant<_IntType, (_IntType)_Val>,
                    _Select_int_base<_Val, _Ints...>>
     { };
 
diff --git a/libstdc++-v3/include/experimental/buffer 
b/libstdc++-v3/include/experimental/buffer
index 8ccdb28cc5b..08d3a365e8d 100644
--- a/libstdc++-v3/include/experimental/buffer
+++ b/libstdc++-v3/include/experimental/buffer
@@ -315,7 +315,7 @@ inline namespace v1
     inline size_t
     buffer_copy(const _MutableBufferSequence& __dest,
                const _ConstBufferSequence& __source) noexcept
-    { return net::buffer_copy(__dest, __source, size_t{-1}); }
+    { return net::buffer_copy(__dest, __source, size_t(-1)); }
 
 
   // buffer arithmetic:
diff --git a/libstdc++-v3/include/experimental/internet 
b/libstdc++-v3/include/experimental/internet
index f1153b8ff6a..1143ef41a5a 100644
--- a/libstdc++-v3/include/experimental/internet
+++ b/libstdc++-v3/include/experimental/internet
@@ -2393,7 +2393,7 @@ namespace ip
     : __hash_base<size_t, experimental::net::v1::ip::address>
     {
       size_t
-      operator()(const argument_type& __a) const
+      operator()(const experimental::net::v1::ip::address& __a) const
       {
        if (__a.is_v4())
          return _Hash_impl::hash(__a.to_v4());
@@ -2407,7 +2407,7 @@ namespace ip
     : __hash_base<size_t, experimental::net::v1::ip::address_v4>
     {
       size_t
-      operator()(const argument_type& __a) const
+      operator()(const experimental::net::v1::ip::address_v4& __a) const
       { return _Hash_impl::hash(__a.to_bytes()); }
     };
 
@@ -2415,7 +2415,7 @@ namespace ip
     : __hash_base<size_t, experimental::net::v1::ip::address_v6>
     {
       size_t
-      operator()(const argument_type& __a) const
+      operator()(const experimental::net::v1::ip::address_v6& __a) const
       { return _Hash_impl::hash(__a.to_bytes()); }
     };
 
diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant
index 17f8bcd638b..4455ff4f073 100644
--- a/libstdc++-v3/include/std/variant
+++ b/libstdc++-v3/include/std/variant
@@ -1512,7 +1512,8 @@ namespace __variant
                }
              __catch (...)
                {
-                 this->_M_index = variant_npos;
+                 using __index_type = decltype(this->_M_index);
+                 this->_M_index = static_cast<__index_type>(variant_npos);
                  __throw_exception_again;
                }
            }
@@ -1559,7 +1560,8 @@ namespace __variant
                }
              __catch (...)
                {
-                 this->_M_index = variant_npos;
+                 using __index_type = decltype(this->_M_index);
+                 this->_M_index = static_cast<__index_type>(variant_npos);
                  __throw_exception_again;
                }
            }