diff --git a/src/Microsoft.OpenApi/Microsoft.OpenApi.csproj b/src/Microsoft.OpenApi/Microsoft.OpenApi.csproj
index 6dbcbf20f..dad533668 100644
--- a/src/Microsoft.OpenApi/Microsoft.OpenApi.csproj
+++ b/src/Microsoft.OpenApi/Microsoft.OpenApi.csproj
@@ -41,6 +41,7 @@
         <EmbeddedResource Update="Properties\SRResource.resx">
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>SRResource.Designer.cs</LastGenOutput>
+            <CustomToolNamespace>Microsoft.OpenApi</CustomToolNamespace>
         </EmbeddedResource>
     </ItemGroup>
 
diff --git a/src/Microsoft.OpenApi/Properties/SRResource.Designer.cs b/src/Microsoft.OpenApi/Properties/SRResource.Designer.cs
index 4e4717e0d..3de246750 100644
--- a/src/Microsoft.OpenApi/Properties/SRResource.Designer.cs
+++ b/src/Microsoft.OpenApi/Properties/SRResource.Designer.cs
@@ -1,6 +1,7 @@
 //------------------------------------------------------------------------------
 // <auto-generated>
 //     This code was generated by a tool.
+//     Runtime Version:4.0.30319.42000
 //
 //     Changes to this file may cause incorrect behavior and will be lost if
 //     the code is regenerated.
@@ -69,25 +70,23 @@ internal static string ActiveScopeNeededForPropertyNameWriting {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to The argument &apos;{0}&apos; is null, empty or consists only of white-space..
+        ///   Looks up a localized string similar to The argument &apos;{0}&apos; is null..
         /// </summary>
-        internal static string ArgumentNullOrWhiteSpace {
+        internal static string ArgumentNull {
             get {
-                return ResourceManager.GetString("ArgumentNullOrWhiteSpace", resourceCulture);
+                return ResourceManager.GetString("ArgumentNull", resourceCulture);
             }
         }
-
+        
         /// <summary>
-        ///   Looks up a localized string similar to The argument &apos;{0}&apos; is null..
+        ///   Looks up a localized string similar to The argument &apos;{0}&apos; is null, empty or consists only of white-space..
         /// </summary>
-        internal static string ArgumentNull
-        {
-            get
-            {
-                return ResourceManager.GetString("ArgumentNull", resourceCulture);
+        internal static string ArgumentNullOrWhiteSpace {
+            get {
+                return ResourceManager.GetString("ArgumentNullOrWhiteSpace", resourceCulture);
             }
         }
-
+        
         /// <summary>
         ///   Looks up a localized string similar to http://localhost/.
         /// </summary>
@@ -412,27 +411,5 @@ internal static string WorkspaceRequredForExternalReferenceResolution {
                 return ResourceManager.GetString("WorkspaceRequredForExternalReferenceResolution", resourceCulture);
             }
         }
-
-        /// <summary>
-        ///   Looks up a localized string similar to The HostDocument is null..
-        /// </summary>
-        internal static string HostDocumentIsNull
-        {
-            get
-            {
-                return ResourceManager.GetString("HostDocumentIsNull", resourceCulture);
-            }
-        }
-
-        /// <summary>
-        ///   Looks up a localized string similar to The identifier in the referenced element is null or empty ..
-        /// </summary>
-        internal static string ReferenceIdIsNullOrEmpty
-        {
-            get
-            {
-                return ResourceManager.GetString("ReferenceIdIsNullOrEmpty", resourceCulture);
-            }
-        }
     }
 }
diff --git a/src/Microsoft.OpenApi/Properties/SRResource.resx b/src/Microsoft.OpenApi/Properties/SRResource.resx
index 0effa1d44..6cd1fc2ba 100644
--- a/src/Microsoft.OpenApi/Properties/SRResource.resx
+++ b/src/Microsoft.OpenApi/Properties/SRResource.resx
@@ -226,9 +226,12 @@
     <value>OpenAPI document must be added to an OpenApiWorkspace to be able to resolve external references.</value>
   </data>
   <data name="ParseServerUrlDefaultValueNotAvailable" xml:space="preserve">
-      <value>Invalid server variable '{0}'. A value was not provided and no default value was provided.</value>
+    <value>Invalid server variable '{0}'. A value was not provided and no default value was provided.</value>
   </data>
   <data name="ParseServerUrlValueNotValid" xml:space="preserve">
-      <value>Value '{0}' is not a valid value for variable '{1}'. If an enum is provided, it should not be empty and the value provided should exist in the enum</value>
+    <value>Value '{0}' is not a valid value for variable '{1}'. If an enum is provided, it should not be empty and the value provided should exist in the enum</value>
   </data>
-</root>
+  <data name="ArgumentNull" xml:space="preserve">
+    <value>The argument '{0}' is null.</value>
+  </data>
+</root>
\ No newline at end of file
diff --git a/src/Microsoft.OpenApi/Validations/ValidationRuleSet.cs b/src/Microsoft.OpenApi/Validations/ValidationRuleSet.cs
index 63baab84d..e5078e7e0 100644
--- a/src/Microsoft.OpenApi/Validations/ValidationRuleSet.cs
+++ b/src/Microsoft.OpenApi/Validations/ValidationRuleSet.cs
@@ -2,9 +2,9 @@
 // Licensed under the MIT license.
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
-using System.Collections.Generic;
 
 namespace Microsoft.OpenApi
 {
@@ -150,12 +150,12 @@ public void Add(Type key, List<ValidationRule> rules)
         /// <exception cref="OpenApiException">Exception thrown when rule already exists.</exception>
         public void Add(Type key, ValidationRule rule)
         {
-            if (!_rulesDictionary.ContainsKey(key))
+            if (!_rulesDictionary.TryGetValue(key, out var rules))
             {
-                _rulesDictionary[key] = [];
+                _rulesDictionary[key] = rules = [];
             }
 
-            if (_rulesDictionary[key].Contains(rule))
+            if (rules.Contains(rule))
             {
                 throw new OpenApiException(SRResource.Validation_RuleAddTwice);
             }
@@ -202,7 +202,7 @@ public void Remove(string ruleName)
             }
 
             // Remove types with no rule
-            _rulesDictionary = _rulesDictionary.Where(r => r.Value.Any()).ToDictionary(r => r.Key, r => r.Value);
+            _rulesDictionary = _rulesDictionary.Where(r => r.Value.Count > 0).ToDictionary(r => r.Key, r => r.Value);
         }
 
         /// <summary>
diff --git a/test/Microsoft.OpenApi.Tests/Validations/ValidationRuleSetTests.cs b/test/Microsoft.OpenApi.Tests/Validations/ValidationRuleSetTests.cs
index 80ac348cb..45a2dfcad 100644
--- a/test/Microsoft.OpenApi.Tests/Validations/ValidationRuleSetTests.cs
+++ b/test/Microsoft.OpenApi.Tests/Validations/ValidationRuleSetTests.cs
@@ -59,7 +59,7 @@ public void RuleSetConstructorsReturnsTheCorrectRules()
         }
 
         [Fact]
-        public void RemoveValidatioRuleGivenTheValidationRuleWorks()
+        public void RemoveValidationRuleGivenTheValidationRuleWorks()
         {
             // Arrange
             var ruleSet = new ValidationRuleSet(_rulesDictionary);
@@ -162,7 +162,7 @@ public void TryGetValueWorks()
             ruleSet.TryGetValue(typeof(OpenApiContact), out var validationRules);
 
             // Assert
-            Assert.True(validationRules.Any());
+            Assert.True(validationRules.Count > 0);
             Assert.Contains(_contactValidationRule, validationRules);
         }
 
@@ -195,7 +195,7 @@ public void GetValidationRuleTypesReturnsAllSupportedTypes()
             var declaredRuleTypeProperties = typeof(ValidationRuleSet).Assembly.GetTypes()
                 .Where(t => t.IsClass
                             && t != typeof(object)
-                            && t.GetCustomAttributes(typeof(OpenApiRuleAttribute), false).Any())
+                            && t.GetCustomAttributes(typeof(OpenApiRuleAttribute), false).Length != 0)
                 .SelectMany(t2 => t2.GetProperties(BindingFlags.Static | BindingFlags.Public))
                 .ToList();