diff --git a/include/nlohmann/detail/input/input_adapters.hpp b/include/nlohmann/detail/input/input_adapters.hpp
index d60af25c..142aba28 100644
--- a/include/nlohmann/detail/input/input_adapters.hpp
+++ b/include/nlohmann/detail/input/input_adapters.hpp
@@ -103,6 +103,7 @@ class input_stream_adapter
         sb = rhs.sb;
         rhs.is = nullptr;
         rhs.sb = nullptr;
+        return *this;
     }
 
     // std::istream/std::streambuf use std::char_traits<char>::to_int_type, to
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 0bd26e87..286e0a29 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -3966,6 +3966,7 @@ class input_stream_adapter
         sb = rhs.sb;
         rhs.is = nullptr;
         rhs.sb = nullptr;
+        return *this;
     }
 
     // std::istream/std::streambuf use std::char_traits<char>::to_int_type, to