diff --git a/include/tao/pq/is_array.hpp b/include/tao/pq/is_array.hpp
index 0329e97..ebefb16 100644
--- a/include/tao/pq/is_array.hpp
+++ b/include/tao/pq/is_array.hpp
@@ -58,14 +58,18 @@ namespace tao::pq
       template< typename T, std::size_t N >
       inline constexpr bool is_array_parameter< std::array< T, N > > = true;
 
-      template< typename T >
-      inline constexpr bool is_array_result = pq::is_array< T >;
-
    }  // namespace internal
 
    template< typename T >
    inline constexpr bool is_array_parameter = internal::is_array_parameter< T >;
 
+   namespace internal
+   {
+      template< typename T >
+      inline constexpr bool is_array_result = pq::is_array< T >;
+
+   }  // namespace internal
+
    template< typename T >
    inline constexpr bool is_array_result = internal::is_array_result< T >;
 
diff --git a/include/tao/pq/parameter.hpp b/include/tao/pq/parameter.hpp
index 403ecb7..78b8012 100644
--- a/include/tao/pq/parameter.hpp
+++ b/include/tao/pq/parameter.hpp
@@ -99,8 +99,8 @@ namespace tao::pq
 
       friend class transaction_base;
 
-      template< typename T, std::size_t... Is >
-      void fill( const T& t, std::index_sequence< Is... > /*unused*/ )
+      template< std::size_t... Is >
+      void fill( const auto& t, std::index_sequence< Is... > /*unused*/ )
       {
          ( ( m_types[ m_size + Is ] = static_cast< Oid >( t.template type< Is >() ) ), ... );
          ( ( m_values[ m_size + Is ] = t.template value< Is >() ), ... );
diff --git a/include/tao/pq/parameter_traits.hpp b/include/tao/pq/parameter_traits.hpp
index 88561cc..13819ab 100644
--- a/include/tao/pq/parameter_traits.hpp
+++ b/include/tao/pq/parameter_traits.hpp
@@ -26,7 +26,7 @@
 
 namespace tao::pq
 {
-   template< typename T >
+   template< typename >
    struct parameter_traits;
 
    namespace internal
@@ -37,8 +37,8 @@ namespace tao::pq
       // helper for table_writer
       void table_writer_append( std::string& buffer, std::string_view data );
 
-      template< std::size_t N, typename T >
-      void snprintf( char ( &buffer )[ N ], const char* format, const T v ) noexcept
+      template< std::size_t N >
+      void snprintf( char ( &buffer )[ N ], const char* format, const auto v ) noexcept
       {
          static_assert( N >= 32 );
          if( std::isfinite( v ) ) {