diff --git a/include/jsoncons/sink.hpp b/include/jsoncons/sink.hpp
index 9802242c9f..934dce0504 100644
--- a/include/jsoncons/sink.hpp
+++ b/include/jsoncons/sink.hpp
@@ -41,6 +41,7 @@ class stream_sink
     // Noncopyable
     stream_sink(const stream_sink&) = delete;
     stream_sink& operator=(const stream_sink&) = delete;
+    stream_sink& operator=(stream_sink&&) = delete;
 
 public:
     stream_sink(stream_sink&&) = default;
@@ -59,8 +60,6 @@ class stream_sink
         os_->flush();
     }
 
-    stream_sink& operator=(stream_sink&&) = default;
-
     void flush()
     {
         os_->write(begin_buffer_, buffer_length());
@@ -124,6 +123,7 @@ class binary_stream_sink
     // Noncopyable
     binary_stream_sink(const binary_stream_sink&) = delete;
     binary_stream_sink& operator=(const binary_stream_sink&) = delete;
+    binary_stream_sink& operator=(binary_stream_sink&&) = delete;
 
 public:
     binary_stream_sink(binary_stream_sink&&) = default;
@@ -150,8 +150,6 @@ class binary_stream_sink
         os_->flush();
     }
 
-    binary_stream_sink& operator=(binary_stream_sink&&) = default;
-
     void flush()
     {
         os_->write((char*)begin_buffer_, buffer_length());
@@ -209,6 +207,7 @@ class string_sink
     // Noncopyable
     string_sink(const string_sink&) = delete;
     string_sink& operator=(const string_sink&) = delete;
+    string_sink& operator=(string_sink&& val) = delete;
 public:
     string_sink(string_sink&& val)
         : s_(nullptr)
@@ -221,11 +220,6 @@ class string_sink
     {
     }
 
-    string_sink& operator=(string_sink&& val)
-    {
-        std::swap(s_, val.s_);
-    }
-
     void flush()
     {
     }
@@ -254,6 +248,7 @@ class bytes_sink
     // Noncopyable
     bytes_sink(const bytes_sink&) = delete;
     bytes_sink& operator=(const bytes_sink&) = delete;
+    bytes_sink& operator=(bytes_sink&&) = delete;
 public:
     bytes_sink(bytes_sink&&) = default;
 
@@ -262,8 +257,6 @@ class bytes_sink
     {
     }
 
-    bytes_sink& operator=(bytes_sink&&) = default;
-
     void flush()
     {
     }
diff --git a/include/jsoncons/staj_reader.hpp b/include/jsoncons/staj_reader.hpp
index e469ee9d4e..a4fabbabf1 100644
--- a/include/jsoncons/staj_reader.hpp
+++ b/include/jsoncons/staj_reader.hpp
@@ -867,7 +867,7 @@ class typed_array
     span<const uint64_t> data(uint64_array_arg_t) const
     {
         JSONCONS_ASSERT(type_ == typed_array_type::uint64_value);
-         span<const uint64_t>(data_.uint64_data_, size_);
+        return span<const uint64_t>(data_.uint64_data_, size_);
     }
 
     span<int8_t> data(int8_array_arg_t)