diff --git a/include/fkYAML/detail/conversions/from_node.hpp b/include/fkYAML/detail/conversions/from_node.hpp
index 50b0df0a..28997654 100644
--- a/include/fkYAML/detail/conversions/from_node.hpp
+++ b/include/fkYAML/detail/conversions/from_node.hpp
@@ -218,7 +218,7 @@ inline void from_node(const BasicNodeType& n, FloatType& f)
         throw exception("Floating point value overflow detected.");
     }
 
-    f = tmp_float;
+    f = static_cast<FloatType>(tmp_float);
 }
 
 /**
diff --git a/include/fkYAML/detail/input/lexical_analyzer.hpp b/include/fkYAML/detail/input/lexical_analyzer.hpp
index 709e33f9..2799494a 100644
--- a/include/fkYAML/detail/input/lexical_analyzer.hpp
+++ b/include/fkYAML/detail/input/lexical_analyzer.hpp
@@ -122,12 +122,14 @@ class lexical_analyzer
             {
             case ' ':
                 break;
-            case '\r':
-                if (m_input_handler.get_next() == '\n')
+            case '\r': {
+                char_int_type next = m_input_handler.get_next();
+                if (next == '\n')
                 {
                     m_input_handler.get_next();
                 }
                 return m_last_token_type = lexical_token_t::MAPPING_BLOCK_PREFIX;
+            }
             case '\n':
                 m_input_handler.get_next();
                 return m_last_token_type = lexical_token_t::MAPPING_BLOCK_PREFIX;
@@ -153,7 +155,7 @@ class lexical_analyzer
                     m_input_handler.get_next();
                     break;
                 }
-                m_value_buffer.push_back(next);
+                m_value_buffer.push_back(char_traits_type::to_char_type(next));
             }
             return m_last_token_type = lexical_token_t::ANCHOR_PREFIX;
         }
@@ -171,7 +173,7 @@ class lexical_analyzer
                     m_input_handler.get_next();
                     break;
                 }
-                m_value_buffer.push_back(next);
+                m_value_buffer.push_back(char_traits_type::to_char_type(next));
             }
             return m_last_token_type = lexical_token_t::ALIAS_PREFIX;
         }
@@ -180,8 +182,9 @@ class lexical_analyzer
             return m_last_token_type = lexical_token_t::COMMENT_PREFIX;
         case '%': // directive prefix
             return m_last_token_type = scan_directive();
-        case '-':
-            if (!m_input_handler.test_next_char(' '))
+        case '-': {
+            bool is_next_space = m_input_handler.test_next_char(' ');
+            if (!is_next_space)
             {
                 return m_last_token_type = scan_number();
             }
@@ -191,6 +194,7 @@ class lexical_analyzer
             m_input_handler.get_next();
 
             return m_last_token_type = lexical_token_t::SEQUENCE_BLOCK_PREFIX;
+        }
         case '[': // sequence flow begin
             m_input_handler.get_next();
             return m_last_token_type = lexical_token_t::SEQUENCE_FLOW_BEGIN;
@@ -212,12 +216,13 @@ class lexical_analyzer
         case '\'':
             return m_last_token_type = scan_string();
         case '~':
-            m_value_buffer = current;
+            m_value_buffer = char_traits_type::to_char_type(current);
             return m_last_token_type = lexical_token_t::NULL_VALUE;
         case '+':
             return m_last_token_type = scan_number();
         case '.': {
-            if (m_input_handler.get_range(4, m_value_buffer) == end_of_input)
+            char_int_type ret = m_input_handler.get_range(4, m_value_buffer);
+            if (ret == end_of_input)
             {
                 return m_last_token_type = scan_string();
             }
@@ -240,7 +245,8 @@ class lexical_analyzer
         case 'f': {
             // YAML specifies that only these words represent the boolean value `false`.
             // See "10.3.2. Tag Resolution" section in https://yaml.org/spec/1.2.2/
-            if (m_input_handler.get_range(5, m_value_buffer) == end_of_input)
+            char_int_type ret = m_input_handler.get_range(5, m_value_buffer);
+            if (ret == end_of_input)
             {
                 return m_last_token_type = scan_string();
             }
@@ -264,7 +270,8 @@ class lexical_analyzer
             // YAML specifies that these words and a tilde represent a null value.
             // Tildes are already checked above, so no check is needed here.
             // See "10.3.2. Tag Resolution" section in https://yaml.org/spec/1.2.2/
-            if (m_input_handler.get_range(4, m_value_buffer) == end_of_input)
+            char_int_type ret = m_input_handler.get_range(4, m_value_buffer);
+            if (ret == end_of_input)
             {
                 return m_last_token_type = scan_string();
             }
@@ -287,7 +294,8 @@ class lexical_analyzer
         case 't': {
             // YAML specifies that only these words represent the boolean value `true`.
             // See "10.3.2. Tag Resolution" section in https://yaml.org/spec/1.2.2/
-            if (m_input_handler.get_range(4, m_value_buffer) == end_of_input)
+            char_int_type ret = m_input_handler.get_range(4, m_value_buffer);
+            if (ret == end_of_input)
             {
                 return m_last_token_type = scan_string();
             }
@@ -495,19 +503,19 @@ class lexical_analyzer
         {
             throw fkyaml::exception("Invalid YAML major version found.");
         }
-        m_value_buffer.push_back(m_input_handler.get_current());
+        m_value_buffer.push_back(char_traits_type::to_char_type(m_input_handler.get_current()));
 
         if (m_input_handler.get_next() != '.')
         {
             throw fkyaml::exception("A period must be followed after the YAML major version.");
         }
-        m_value_buffer.push_back(m_input_handler.get_current());
+        m_value_buffer.push_back(char_traits_type::to_char_type(m_input_handler.get_current()));
 
         switch (m_input_handler.get_next())
         {
         case '1':
         case '2':
-            m_value_buffer.push_back(m_input_handler.get_current());
+            m_value_buffer.push_back(char_traits_type::to_char_type(m_input_handler.get_current()));
             break;
         case '0':
         case '3':
@@ -548,14 +556,14 @@ class lexical_analyzer
         switch (current)
         {
         case '-':
-            m_value_buffer.push_back(current);
+            m_value_buffer.push_back(char_traits_type::to_char_type(current));
             ret = scan_negative_number();
             break;
         case '+':
             ret = scan_decimal_number();
             break;
         case '0':
-            m_value_buffer.push_back(current);
+            m_value_buffer.push_back(char_traits_type::to_char_type(current));
             ret = scan_number_after_zero_at_first();
             break;
         case '1':
@@ -567,7 +575,7 @@ class lexical_analyzer
         case '7':
         case '8':
         case '9':
-            m_value_buffer.push_back(current);
+            m_value_buffer.push_back(char_traits_type::to_char_type(current));
             ret = scan_decimal_number();
             break;
         default:                                                                   // LCOV_EXCL_LINE
@@ -601,11 +609,12 @@ class lexical_analyzer
 
         if (std::isdigit(next))
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             return scan_decimal_number();
         }
 
-        if (m_input_handler.get_range(4, m_value_buffer) != end_of_input)
+        char_int_type ret = m_input_handler.get_range(4, m_value_buffer);
+        if (ret != end_of_input)
         {
             try
             {
@@ -634,7 +643,7 @@ class lexical_analyzer
         switch (next)
         {
         case '.':
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             return scan_decimal_number_after_decimal_point();
         case 'o':
             // Do not store 'o' since std::strtoull does not support "0o" but "0" as the prefix for octal numbers.
@@ -642,7 +651,7 @@ class lexical_analyzer
             // See "10.3.2. Tag Resolution" section in https://yaml.org/spec/1.2.2/
             return scan_octal_number();
         case 'x':
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             return scan_hexadecimal_number();
         default:
             return lexical_token_t::INTEGER_VALUE;
@@ -660,7 +669,7 @@ class lexical_analyzer
 
         if (std::isdigit(next))
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             scan_decimal_number();
             return lexical_token_t::FLOAT_NUMBER_VALUE;
         }
@@ -678,12 +687,12 @@ class lexical_analyzer
         char_int_type next = m_input_handler.get_next();
         if (next == '+' || next == '-')
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             scan_decimal_number_after_sign();
         }
         else if (std::isdigit(next))
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             scan_decimal_number();
         }
         else
@@ -704,7 +713,7 @@ class lexical_analyzer
 
         if (std::isdigit(next))
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             return scan_decimal_number();
         }
 
@@ -722,24 +731,25 @@ class lexical_analyzer
 
         if (std::isdigit(next))
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             return scan_decimal_number();
         }
 
         if (next == '.')
         {
-            if (m_value_buffer.find(next) != string_type::npos) // NOLINT(abseil-string-find-str-contains)
+            // NOLINTNEXTLINE(abseil-string-find-str-contains)
+            if (m_value_buffer.find(char_traits_type::to_char_type(next)) != string_type::npos)
             {
                 // TODO: support this use case (e.g. version info like 1.0.0)
                 throw fkyaml::exception("Multiple decimal points found in a token.");
             }
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             return scan_decimal_number_after_decimal_point();
         }
 
         if (next == 'e' || next == 'E')
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             return scan_decimal_number_after_exponent();
         }
 
@@ -756,7 +766,7 @@ class lexical_analyzer
         char_int_type next = m_input_handler.get_next();
         if ('0' <= next && next <= '7')
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             scan_octal_number();
         }
         return lexical_token_t::INTEGER_VALUE;
@@ -772,7 +782,7 @@ class lexical_analyzer
         char_int_type next = m_input_handler.get_next();
         if (std::isxdigit(next))
         {
-            m_value_buffer.push_back(next);
+            m_value_buffer.push_back(char_traits_type::to_char_type(next));
             scan_hexadecimal_number();
         }
         return lexical_token_t::INTEGER_VALUE;
@@ -818,7 +828,7 @@ class lexical_analyzer
                 {
                     return lexical_token_t::STRING_VALUE;
                 }
-                m_value_buffer.push_back(current);
+                m_value_buffer.push_back(char_traits_type::to_char_type(current));
                 continue;
             }
 
@@ -836,7 +846,7 @@ class lexical_analyzer
                 }
 
                 // if the target is a single-quoted string token.
-                m_value_buffer.push_back(current);
+                m_value_buffer.push_back(char_traits_type::to_char_type(current));
                 continue;
             }
 
@@ -850,9 +860,10 @@ class lexical_analyzer
 
                 // If single quotation marks are repeated twice in a single-quoted string token. they are considered as
                 // an escaped single quotation mark.
-                if (m_input_handler.test_next_char('\''))
+                bool is_next_single_quote = m_input_handler.test_next_char('\'');
+                if (is_next_single_quote)
                 {
-                    m_value_buffer.push_back(m_input_handler.get_next());
+                    m_value_buffer.push_back(char_traits_type::to_char_type(m_input_handler.get_next()));
                     continue;
                 }
 
@@ -865,7 +876,7 @@ class lexical_analyzer
                 // Just regard a colon as a character if surrounded by quotation marks.
                 if (needs_last_double_quote || needs_last_single_quote)
                 {
-                    m_value_buffer.push_back(current);
+                    m_value_buffer.push_back(char_traits_type::to_char_type(current));
                     continue;
                 }
 
@@ -875,7 +886,7 @@ class lexical_analyzer
                 // A colon as a key separator must be followed by a space or a newline code.
                 if (next != ' ' && next != '\r' && next != '\n')
                 {
-                    m_value_buffer.push_back(current);
+                    m_value_buffer.push_back(char_traits_type::to_char_type(current));
                     continue;
                 }
 
@@ -895,7 +906,7 @@ class lexical_analyzer
                 // Just regard a comma as a character if surrounded by quotation marks.
                 if (needs_last_double_quote || needs_last_single_quote)
                 {
-                    m_value_buffer.push_back(current);
+                    m_value_buffer.push_back(char_traits_type::to_char_type(current));
                     continue;
                 }
 
@@ -908,7 +919,7 @@ class lexical_analyzer
                 // just regard a right square bracket as a character if surrounded by quotation marks.
                 if (needs_last_double_quote || needs_last_single_quote)
                 {
-                    m_value_buffer.push_back(current);
+                    m_value_buffer.push_back(char_traits_type::to_char_type(current));
                     continue;
                 }
 
@@ -921,7 +932,7 @@ class lexical_analyzer
                 // just regard a right curly brace as a character if surrounded by quotation marks.
                 if (needs_last_double_quote || needs_last_single_quote)
                 {
-                    m_value_buffer.push_back(current);
+                    m_value_buffer.push_back(char_traits_type::to_char_type(current));
                     continue;
                 }
 
@@ -1018,7 +1029,7 @@ class lexical_analyzer
             // Handle ASCII characters except control characters.
             if (current <= 0x7E)
             {
-                m_value_buffer.push_back(current);
+                m_value_buffer.push_back(char_traits_type::to_char_type(current));
                 continue;
             }
 
@@ -1056,7 +1067,7 @@ class lexical_analyzer
         case 0x08:
             throw fkyaml::exception("Control character U+0008 (BS) must be escaped to \\b or \\u0008.");
         case 0x09: // HT
-            m_value_buffer.push_back(c);
+            m_value_buffer.push_back(char_traits_type::to_char_type(c));
             break;
         // 0x0A(LF) has already been handled above.
         case 0x0B:
diff --git a/include/fkYAML/detail/iterator.hpp b/include/fkYAML/detail/iterator.hpp
index e507a8db..4f10101b 100644
--- a/include/fkYAML/detail/iterator.hpp
+++ b/include/fkYAML/detail/iterator.hpp
@@ -172,7 +172,7 @@ class iterator
      *
      * @param other An iterator object to be copied with.
      */
-    iterator(const iterator& other) noexcept // NOLINT(bugprone-exception-escape)
+    iterator(const iterator& other)
         : m_inner_iterator_type(other.m_inner_iterator_type)
     {
         switch (m_inner_iterator_type)
@@ -193,7 +193,7 @@ class iterator
      *
      * @param other An iterator object to be moved from.
      */
-    iterator(iterator&& other) noexcept // NOLINT(bugprone-exception-escape)
+    iterator(iterator&& other)
         : m_inner_iterator_type(other.m_inner_iterator_type)
     {
         switch (m_inner_iterator_type)
@@ -218,7 +218,7 @@ class iterator
      * @param rhs An iterator object to be copied with.
      * @return iterator& Reference to this iterator object.
      */
-    iterator& operator=(const iterator& rhs) noexcept // NOLINT(cert-oop54-cpp,bugprone-exception-escape)
+    iterator& operator=(const iterator& rhs) // NOLINT(cert-oop54-cpp)
     {
         if (&rhs == this)
         {
@@ -247,7 +247,7 @@ class iterator
      * @param rhs An iterator object to be moved from.
      * @return iterator& Reference to this iterator object.
      */
-    iterator& operator=(iterator&& rhs) noexcept // NOLINT(bugprone-exception-escape)
+    iterator& operator=(iterator&& rhs)
     {
         if (&rhs == this)
         {
@@ -275,7 +275,7 @@ class iterator
      *
      * @return pointer A pointer to the BasicNodeType object internally referenced by the actual iterator object.
      */
-    pointer operator->() noexcept // NOLINT(bugprone-exception-escape)
+    pointer operator->()
     {
         switch (m_inner_iterator_type)
         {
@@ -293,7 +293,7 @@ class iterator
      *
      * @return reference Reference to the Node object internally referenced by the actual iterator object.
      */
-    reference operator*() noexcept // NOLINT(bugprone-exception-escape)
+    reference operator*()
     {
         switch (m_inner_iterator_type)
         {
@@ -312,7 +312,7 @@ class iterator
      * @param i The difference from this Iterator object with which it moves forward.
      * @return Iterator& Reference to this Iterator object.
      */
-    iterator& operator+=(difference_type i) noexcept // NOLINT(bugprone-exception-escape)
+    iterator& operator+=(difference_type i)
     {
         switch (m_inner_iterator_type)
         {
@@ -346,7 +346,7 @@ class iterator
      *
      * @return iterator& Reference to this iterator object.
      */
-    iterator& operator++() noexcept // NOLINT(bugprone-exception-escape)
+    iterator& operator++()
     {
         switch (m_inner_iterator_type)
         {
@@ -380,7 +380,7 @@ class iterator
      * @param i The difference from this iterator object with which it moves backward.
      * @return iterator& Reference to this iterator object.
      */
-    iterator& operator-=(difference_type i) noexcept // NOLINT(bugprone-exception-escape)
+    iterator& operator-=(difference_type i)
     {
         return operator+=(-i);
     }
@@ -403,7 +403,7 @@ class iterator
      *
      * @return iterator& Reference to this iterator object.
      */
-    iterator& operator--() noexcept // NOLINT(bugprone-exception-escape)
+    iterator& operator--()
     {
         switch (m_inner_iterator_type)
         {
@@ -563,7 +563,7 @@ class iterator
      *
      * @return reference A reference to the YAML node for the current iterator.
      */
-    reference value() noexcept // NOLINT(bugprone-exception-escape)
+    reference value()
     {
         return operator*();
     }
diff --git a/include/fkYAML/detail/output/serializer.hpp b/include/fkYAML/detail/output/serializer.hpp
index 9f6ef9c1..82e3c258 100644
--- a/include/fkYAML/detail/output/serializer.hpp
+++ b/include/fkYAML/detail/output/serializer.hpp
@@ -77,7 +77,8 @@ class basic_serializer
             {
                 insert_indentation(cur_indent, str);
                 str += "-";
-                if (seq_item.is_scalar())
+                bool is_scalar = seq_item.is_scalar();
+                if (is_scalar)
                 {
                     str += " ";
                     serialize_node(seq_item, cur_indent, str);
@@ -95,7 +96,8 @@ class basic_serializer
             {
                 insert_indentation(cur_indent, str);
                 serialize_key(itr.key(), str);
-                if (itr->is_scalar())
+                bool is_scalar = itr->is_scalar();
+                if (is_scalar)
                 {
                     str += " ";
                     serialize_node(*itr, cur_indent, str);
diff --git a/include/fkYAML/node.hpp b/include/fkYAML/node.hpp
index 592e4086..e48c0a35 100644
--- a/include/fkYAML/node.hpp
+++ b/include/fkYAML/node.hpp
@@ -358,7 +358,7 @@ class basic_node
      *
      * @param[in] rhs A basic_node object to be moved from.
      */
-    basic_node(basic_node&& rhs) noexcept // NOLINT(bugprone-exception-escape)
+    basic_node(basic_node&& rhs) noexcept
         : m_node_type(rhs.m_node_type),
           m_yaml_version_type(rhs.m_yaml_version_type),
           m_anchor_name(rhs.m_anchor_name)
@@ -396,8 +396,6 @@ class basic_node
             m_node_value.p_string = rhs.m_node_value.p_string;
             rhs.m_node_value.p_string = nullptr;
             break;
-        default:                                                     // LCOV_EXCL_LINE
-            throw fkyaml::exception("Unsupported node value type."); // LCOV_EXCL_LINE
         }
 
         rhs.m_node_type = node_t::NULL_OBJECT;
diff --git a/test/unit_test/CMakeLists.txt b/test/unit_test/CMakeLists.txt
index 2522d0ea..022d5f34 100644
--- a/test/unit_test/CMakeLists.txt
+++ b/test/unit_test/CMakeLists.txt
@@ -21,8 +21,12 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
   set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Od")
 elseif(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pedantic -Wno-terminate")
+  # necessary to build iterator class test.
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-self-move")
 elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wno-c++98-compat -Wno-c++98-compat-pedantic")
+  # necessary to build iterator class test.
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-self-assign-overloaded -Wno-self-move")
 endif()
 
 # determine C++ standard used in unit test app.
diff --git a/test/unit_test/test_node_class.cpp b/test/unit_test/test_node_class.cpp
index de22811c..fca6b458 100644
--- a/test/unit_test/test_node_class.cpp
+++ b/test/unit_test/test_node_class.cpp
@@ -1547,9 +1547,9 @@ TEST_CASE("NodeClassTest_GetValueTest", "[NodeClassTest]")
 
         SECTION("test for float number values.")
         {
-            REQUIRE(fabsf(node.get_value<float>() - 3.14) < FLT_EPSILON);
-            REQUIRE(fabsf(node.get_value<double>() - 3.14) < DBL_EPSILON);
-            REQUIRE(fabsf(node.get_value<long double>() - 3.14) < LDBL_EPSILON);
+            REQUIRE(std::abs(node.get_value<float>() - 3.14) < std::numeric_limits<float>::epsilon());
+            REQUIRE(std::abs(node.get_value<double>() - 3.14) < std::numeric_limits<double>::epsilon());
+            REQUIRE(std::abs(node.get_value<long double>() - 3.14) < std::numeric_limits<long double>::epsilon());
         }
 
         SECTION("test for non-float-number values.")