Simplify null check by using a coalescing operator

Author: MaggieKimani1

src/Microsoft.OpenApi/Models/OpenApiDocument.cs

@@ -199,10 +199,7 @@ public void Serialize(IOpenApiWriter writer)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             writer.WriteStartObject();
 

src/Microsoft.OpenApi/Models/OpenApiExtensibleDictionary.cs

@@ -81,10 +81,7 @@ public void Serialize(IOpenApiWriter writer)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             writer.WriteStartObject();
 

src/Microsoft.OpenApi/Models/OpenApiHeader.cs

@@ -222,10 +222,7 @@ public void SerializeAsV3WithoutReference(IOpenApiWriter writer)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             var target = this;
 

src/Microsoft.OpenApi/Models/OpenApiInfo.cs

@@ -130,10 +130,7 @@ public void Serialize(IOpenApiWriter writer)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             writer.WriteStartObject();
 

src/Microsoft.OpenApi/Models/OpenApiOperation.cs

@@ -209,10 +209,7 @@ public void Serialize(IOpenApiWriter writer)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             writer.WriteStartObject();
 

src/Microsoft.OpenApi/Models/OpenApiParameter.cs

@@ -284,10 +284,7 @@ public void SerializeAsV3WithoutReference(IOpenApiWriter writer)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             var target = this;
             if (Reference != null)

src/Microsoft.OpenApi/Models/OpenApiPathItem.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. 
 
 using System.Collections.Generic;
@@ -146,10 +146,7 @@ public OpenApiPathItem GetEffective(OpenApiDocument doc)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             var target = this;
 

src/Microsoft.OpenApi/Models/OpenApiResponse.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. 
 
 using System.Collections.Generic;
@@ -157,10 +157,7 @@ public void SerializeAsV3WithoutReference(IOpenApiWriter writer)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             var target = this;
 

src/Microsoft.OpenApi/Models/OpenApiSchema.cs

@@ -510,10 +510,7 @@ internal void SerializeAsV2(
             ISet<string> parentRequiredProperties,
             string propertyName)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             var settings = writer.GetSettings();
             var target = this;

src/Microsoft.OpenApi/Models/OpenApiSecurityRequirement.cs

@@ -86,10 +86,7 @@ public void Serialize(IOpenApiWriter writer)
         /// </summary>
         public void SerializeAsV2(IOpenApiWriter writer)
         {
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
+            writer = writer ?? throw Error.ArgumentNull(nameof(writer));
 
             writer.WriteStartObject();