diff --git a/include/nlohmann/detail/conversions/to_json.hpp b/include/nlohmann/detail/conversions/to_json.hpp
index 0a802369..b944bf6c 100644
--- a/include/nlohmann/detail/conversions/to_json.hpp
+++ b/include/nlohmann/detail/conversions/to_json.hpp
@@ -306,7 +306,7 @@ void to_json(BasicJsonType& j, const std::pair<Args...>& p)
 // for https://github.com/nlohmann/json/pull/1134
 template<typename BasicJsonType, typename T,
          enable_if_t<std::is_same<T, typename iteration_proxy<typename BasicJsonType::iterator>::iteration_proxy_internal>::value, int> = 0>
-void to_json(BasicJsonType& j, T b) noexcept
+void to_json(BasicJsonType& j, const T& b)
 {
     j = {{b.key(), b.value()}};
 }
diff --git a/include/nlohmann/detail/input/lexer.hpp b/include/nlohmann/detail/input/lexer.hpp
index 44165ff0..b4ff65fb 100644
--- a/include/nlohmann/detail/input/lexer.hpp
+++ b/include/nlohmann/detail/input/lexer.hpp
@@ -709,7 +709,7 @@ class lexer
           locale's decimal point is used instead of `.` to work with the
           locale-dependent converters.
     */
-    token_type scan_number()
+    token_type scan_number()  // lgtm [cpp/use-of-goto]
     {
         // reset token_buffer to store the number's bytes
         reset();
diff --git a/include/nlohmann/detail/json_pointer.hpp b/include/nlohmann/detail/json_pointer.hpp
index fce8001a..320730ec 100644
--- a/include/nlohmann/detail/json_pointer.hpp
+++ b/include/nlohmann/detail/json_pointer.hpp
@@ -506,11 +506,11 @@ class json_pointer
             std::size_t slash = reference_string.find_first_of('/', 1),
             // set the beginning of the first reference token
             start = 1;
-            // we can stop if start == string::npos+1 = 0
+            // we can stop if start == 0 (if slash == std::string::npos)
             start != 0;
             // set the beginning of the next reference token
             // (will eventually be 0 if slash == std::string::npos)
-            start = slash + 1,
+            start = (slash == std::string::npos) ? 0 : slash + 1,
             // find next slash
             slash = reference_string.find_first_of('/', start))
         {
diff --git a/include/nlohmann/detail/output/serializer.hpp b/include/nlohmann/detail/output/serializer.hpp
index e2655f04..d4a258da 100644
--- a/include/nlohmann/detail/output/serializer.hpp
+++ b/include/nlohmann/detail/output/serializer.hpp
@@ -442,7 +442,7 @@ class serializer
             return;
         }
 
-        const bool is_negative = not (x >= 0);  // see issue #755
+        const bool is_negative = std::is_same<NumberType, number_integer_t>::value and not (x >= 0);  // see issue #755
         std::size_t i = 0;
 
         while (x != 0)
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index c40620ad..d62638bd 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -1839,7 +1839,7 @@ void to_json(BasicJsonType& j, const std::pair<Args...>& p)
 // for https://github.com/nlohmann/json/pull/1134
 template<typename BasicJsonType, typename T,
          enable_if_t<std::is_same<T, typename iteration_proxy<typename BasicJsonType::iterator>::iteration_proxy_internal>::value, int> = 0>
-void to_json(BasicJsonType& j, T b) noexcept
+void to_json(BasicJsonType& j, const T& b)
 {
     j = {{b.key(), b.value()}};
 }
@@ -2976,7 +2976,7 @@ class lexer
           locale's decimal point is used instead of `.` to work with the
           locale-dependent converters.
     */
-    token_type scan_number()
+    token_type scan_number()  // lgtm [cpp/use-of-goto]
     {
         // reset token_buffer to store the number's bytes
         reset();
@@ -10157,7 +10157,7 @@ class serializer
             return;
         }
 
-        const bool is_negative = not (x >= 0);  // see issue #755
+        const bool is_negative = std::is_same<NumberType, number_integer_t>::value and not (x >= 0);  // see issue #755
         std::size_t i = 0;
 
         while (x != 0)
@@ -10922,11 +10922,11 @@ class json_pointer
             std::size_t slash = reference_string.find_first_of('/', 1),
             // set the beginning of the first reference token
             start = 1;
-            // we can stop if start == string::npos+1 = 0
+            // we can stop if start == 0 (if slash == std::string::npos)
             start != 0;
             // set the beginning of the next reference token
             // (will eventually be 0 if slash == std::string::npos)
-            start = slash + 1,
+            start = (slash == std::string::npos) ? 0 : slash + 1,
             // find next slash
             slash = reference_string.find_first_of('/', start))
         {