diff --git a/X10D/src/Collections/DictionaryExtensions.cs b/X10D/src/Collections/DictionaryExtensions.cs
index f2594a0..bb13e05 100644
--- a/X10D/src/Collections/DictionaryExtensions.cs
+++ b/X10D/src/Collections/DictionaryExtensions.cs
@@ -1,4 +1,4 @@
-using System.Diagnostics.Contracts;
+using System.Diagnostics.Contracts;
 using System.Runtime.InteropServices;
 using System.Web;
 
@@ -37,15 +37,13 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(dictionary);
+        ArgumentNullException.ThrowIfNull(updateValueFactory);
 #else
         if (dictionary is null)
         {
             throw new ArgumentNullException(nameof(dictionary));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(updateValueFactory);
-#else
+
         if (updateValueFactory is null)
         {
             throw new ArgumentNullException(nameof(updateValueFactory));
@@ -108,15 +106,13 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(dictionary);
+        ArgumentNullException.ThrowIfNull(updateValueFactory);
 #else
         if (dictionary is null)
         {
             throw new ArgumentNullException(nameof(dictionary));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(updateValueFactory);
-#else
+
         if (updateValueFactory is null)
         {
             throw new ArgumentNullException(nameof(updateValueFactory));
@@ -167,23 +163,19 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(dictionary);
+        ArgumentNullException.ThrowIfNull(addValueFactory);
+        ArgumentNullException.ThrowIfNull(updateValueFactory);
 #else
         if (dictionary is null)
         {
             throw new ArgumentNullException(nameof(dictionary));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(addValueFactory);
-#else
+
         if (addValueFactory is null)
         {
             throw new ArgumentNullException(nameof(addValueFactory));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(updateValueFactory);
-#else
+
         if (updateValueFactory is null)
         {
             throw new ArgumentNullException(nameof(updateValueFactory));
@@ -250,23 +242,19 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(dictionary);
+        ArgumentNullException.ThrowIfNull(addValueFactory);
+        ArgumentNullException.ThrowIfNull(updateValueFactory);
 #else
         if (dictionary is null)
         {
             throw new ArgumentNullException(nameof(dictionary));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(addValueFactory);
-#else
+
         if (addValueFactory is null)
         {
             throw new ArgumentNullException(nameof(addValueFactory));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(updateValueFactory);
-#else
+
         if (updateValueFactory is null)
         {
             throw new ArgumentNullException(nameof(updateValueFactory));
@@ -325,23 +313,19 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(dictionary);
+        ArgumentNullException.ThrowIfNull(addValueFactory);
+        ArgumentNullException.ThrowIfNull(updateValueFactory);
 #else
         if (dictionary is null)
         {
             throw new ArgumentNullException(nameof(dictionary));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(addValueFactory);
-#else
+
         if (addValueFactory is null)
         {
             throw new ArgumentNullException(nameof(addValueFactory));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(updateValueFactory);
-#else
+
         if (updateValueFactory is null)
         {
             throw new ArgumentNullException(nameof(updateValueFactory));
@@ -414,23 +398,19 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(dictionary);
+        ArgumentNullException.ThrowIfNull(addValueFactory);
+        ArgumentNullException.ThrowIfNull(updateValueFactory);
 #else
         if (dictionary is null)
         {
             throw new ArgumentNullException(nameof(dictionary));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(addValueFactory);
-#else
+
         if (addValueFactory is null)
         {
             throw new ArgumentNullException(nameof(addValueFactory));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(updateValueFactory);
-#else
+
         if (updateValueFactory is null)
         {
             throw new ArgumentNullException(nameof(updateValueFactory));
@@ -514,15 +494,13 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(source);
+        ArgumentNullException.ThrowIfNull(selector);
 #else
         if (source is null)
         {
             throw new ArgumentNullException(nameof(source));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(selector);
-#else
+
         if (selector is null)
         {
             throw new ArgumentNullException(nameof(selector));
@@ -575,23 +553,19 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(source);
+        ArgumentNullException.ThrowIfNull(keySelector);
+        ArgumentNullException.ThrowIfNull(valueSelector);
 #else
         if (source is null)
         {
             throw new ArgumentNullException(nameof(source));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(keySelector);
-#else
+
         if (keySelector is null)
         {
             throw new ArgumentNullException(nameof(keySelector));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(valueSelector);
-#else
+
         if (valueSelector is null)
         {
             throw new ArgumentNullException(nameof(valueSelector));
@@ -669,15 +643,13 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(source);
+        ArgumentNullException.ThrowIfNull(selector);
 #else
         if (source is null)
         {
             throw new ArgumentNullException(nameof(source));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(selector);
-#else
+
         if (selector is null)
         {
             throw new ArgumentNullException(nameof(selector));
@@ -722,23 +694,19 @@ public static class DictionaryExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(source);
+        ArgumentNullException.ThrowIfNull(keySelector);
+        ArgumentNullException.ThrowIfNull(valueSelector);
 #else
         if (source is null)
         {
             throw new ArgumentNullException(nameof(source));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(keySelector);
-#else
+
         if (keySelector is null)
         {
             throw new ArgumentNullException(nameof(keySelector));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(valueSelector);
-#else
+
         if (valueSelector is null)
         {
             throw new ArgumentNullException(nameof(valueSelector));
diff --git a/X10D/src/Core/RandomExtensions.cs b/X10D/src/Core/RandomExtensions.cs
index c4cc672..32acc3b 100644
--- a/X10D/src/Core/RandomExtensions.cs
+++ b/X10D/src/Core/RandomExtensions.cs
@@ -157,15 +157,13 @@ public static class RandomExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(random);
+        ArgumentNullException.ThrowIfNull(source);
 #else
         if (random is null)
         {
             throw new ArgumentNullException(nameof(random));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(source);
-#else
+
         if (source is null)
         {
             throw new ArgumentNullException(nameof(source));
@@ -534,15 +532,13 @@ public static class RandomExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(random);
+        ArgumentNullException.ThrowIfNull(source);
 #else
         if (random is null)
         {
             throw new ArgumentNullException(nameof(random));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(source);
-#else
+
         if (source is null)
         {
             throw new ArgumentNullException(nameof(source));
diff --git a/X10D/src/IO/ListOfByteExtensions.cs b/X10D/src/IO/ListOfByteExtensions.cs
index d48e8e5..3289fef 100644
--- a/X10D/src/IO/ListOfByteExtensions.cs
+++ b/X10D/src/IO/ListOfByteExtensions.cs
@@ -210,15 +210,13 @@ public static class ListOfByteExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(source);
+        ArgumentNullException.ThrowIfNull(encoding);
 #else
         if (source is null)
         {
             throw new ArgumentNullException(nameof(source));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(encoding);
-#else
+
         if (encoding is null)
         {
             throw new ArgumentNullException(nameof(encoding));
diff --git a/X10D/src/Reflection/MemberInfoExtensions.cs b/X10D/src/Reflection/MemberInfoExtensions.cs
index b54f9b4..24039e0 100644
--- a/X10D/src/Reflection/MemberInfoExtensions.cs
+++ b/X10D/src/Reflection/MemberInfoExtensions.cs
@@ -60,15 +60,13 @@ public static class MemberInfoExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(member);
+        ArgumentNullException.ThrowIfNull(attribute);
 #else
         if (member is null)
         {
             throw new ArgumentNullException(nameof(member));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(attribute);
-#else
+
         if (attribute is null)
         {
             throw new ArgumentNullException(nameof(attribute));
@@ -105,15 +103,13 @@ public static class MemberInfoExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(member);
+        ArgumentNullException.ThrowIfNull(selector);
 #else
         if (member is null)
         {
             throw new ArgumentNullException(nameof(member));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(selector);
-#else
+
         if (selector is null)
         {
             throw new ArgumentNullException(nameof(selector));
@@ -145,15 +141,13 @@ public static class MemberInfoExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(member);
+        ArgumentNullException.ThrowIfNull(selector);
 #else
         if (member is null)
         {
             throw new ArgumentNullException(nameof(member));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(selector);
-#else
+
         if (selector is null)
         {
             throw new ArgumentNullException(nameof(selector));
diff --git a/X10D/src/Reflection/TypeExtensions.cs b/X10D/src/Reflection/TypeExtensions.cs
index 9d53c39..6f56d62 100644
--- a/X10D/src/Reflection/TypeExtensions.cs
+++ b/X10D/src/Reflection/TypeExtensions.cs
@@ -57,15 +57,13 @@ public static class TypeExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(value);
+        ArgumentNullException.ThrowIfNull(interfaceType);
 #else
         if (value is null)
         {
             throw new ArgumentNullException(nameof(value));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(interfaceType);
-#else
+
         if (interfaceType is null)
         {
             throw new ArgumentNullException(nameof(interfaceType));
@@ -144,15 +142,13 @@ public static class TypeExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(value);
+        ArgumentNullException.ThrowIfNull(type);
 #else
         if (value is null)
         {
             throw new ArgumentNullException(nameof(value));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(type);
-#else
+
         if (type is null)
         {
             throw new ArgumentNullException(nameof(type));
diff --git a/X10D/src/Text/StringExtensions.cs b/X10D/src/Text/StringExtensions.cs
index 43aed4e..28d7693 100644
--- a/X10D/src/Text/StringExtensions.cs
+++ b/X10D/src/Text/StringExtensions.cs
@@ -136,23 +136,19 @@ public static class StringExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(value);
+        ArgumentNullException.ThrowIfNull(sourceEncoding);
+        ArgumentNullException.ThrowIfNull(destinationEncoding);
 #else
         if (value is null)
         {
             throw new ArgumentNullException(nameof(value));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(sourceEncoding);
-#else
+
         if (sourceEncoding is null)
         {
             throw new ArgumentNullException(nameof(sourceEncoding));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(destinationEncoding);
-#else
+
         if (destinationEncoding is null)
         {
             throw new ArgumentNullException(nameof(destinationEncoding));
@@ -478,15 +474,13 @@ public static class StringExtensions
     {
 #if NET6_0_OR_GREATER
         ArgumentNullException.ThrowIfNull(value);
+        ArgumentNullException.ThrowIfNull(encoding);
 #else
         if (value is null)
         {
             throw new ArgumentNullException(nameof(value));
         }
-#endif
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(encoding);
-#else
+
         if (encoding is null)
         {
             throw new ArgumentNullException(nameof(encoding));