use some pattern matching

src/Microsoft.OpenApi.Hidi/OpenApiService.cs

@@ -510,13 +510,15 @@ private static async Task<Stream> GetStream(string input, ILogger logger, Cancel
                         var fileInput = new FileInfo(input);
                         stream = fileInput.OpenRead();
                     }
-                    catch (Exception ex) when (ex is FileNotFoundException ||
-                        ex is PathTooLongException ||
-                        ex is DirectoryNotFoundException ||
-                        ex is IOException ||
-                        ex is UnauthorizedAccessException ||
-                        ex is SecurityException ||
-                        ex is NotSupportedException)
+                    catch (Exception ex) when (
+                        ex is
+                            FileNotFoundException or
+                            PathTooLongException or
+                            DirectoryNotFoundException or
+                            IOException or
+                            UnauthorizedAccessException or
+                            SecurityException or
+                            NotSupportedException)
                     {
                         throw new InvalidOperationException($"Could not open the file at {input}", ex);
                     }

src/Microsoft.OpenApi.Readers/ParseNodes/OpenApiAnyConverter.cs

@@ -116,7 +116,7 @@ public static IOpenApiAny GetSpecificOpenApiAny(IOpenApiAny openApiAny, OpenApiS
                 return openApiAny;
             }
 
-            if (value == null || value == "null")
+            if (value is null or "null")
             {
                 return new OpenApiNull();
             }

src/Microsoft.OpenApi.Readers/ParseNodes/ValueNode.cs

@@ -34,7 +34,7 @@ public override string GetScalarValue()
         public override IOpenApiAny CreateAny()
         {
             var value = GetScalarValue();
-            return new OpenApiString(value, this._node.Style == ScalarStyle.SingleQuoted || this._node.Style == ScalarStyle.DoubleQuoted || this._node.Style == ScalarStyle.Literal || this._node.Style == ScalarStyle.Folded);
+            return new OpenApiString(value, this._node.Style is ScalarStyle.SingleQuoted or ScalarStyle.DoubleQuoted or ScalarStyle.Literal or ScalarStyle.Folded);
         }
     }
 }

src/Microsoft.OpenApi.Readers/ParsingContext.cs

@@ -60,7 +60,7 @@ internal OpenApiDocument Parse(YamlDocument yamlDocument)
 
             switch (inputVersion)
             {
-                case string version when version == "2.0":
+                case string and "2.0":
                     VersionService = new OpenApiV2VersionService(Diagnostic);
                     doc = VersionService.LoadDocument(RootNode);
                     this.Diagnostic.SpecificationVersion = OpenApiSpecVersion.OpenApi2_0;

src/Microsoft.OpenApi.Readers/V2/OpenApiV2VersionService.cs

@@ -152,7 +152,7 @@ public OpenApiReference ConvertToOpenApiReference(string reference, ReferenceTyp
                         };
                     }
 
-                    if (type == ReferenceType.Tag || type == ReferenceType.SecurityScheme)
+                    if (type is ReferenceType.Tag or ReferenceType.SecurityScheme)
                     {
                         return new OpenApiReference
                         {

src/Microsoft.OpenApi.Readers/V3/OpenApiV3VersionService.cs

@@ -78,7 +78,7 @@ public OpenApiReference ConvertToOpenApiReference(
                 var segments = reference.Split('#');
                 if (segments.Length == 1)
                 {
-                    if (type == ReferenceType.Tag || type == ReferenceType.SecurityScheme)
+                    if (type is ReferenceType.Tag or ReferenceType.SecurityScheme)
                     {
                         return new OpenApiReference
                         {

src/Microsoft.OpenApi/MicrosoftExtensions/OpenApiEnumValuesDescriptionExtension.cs

@@ -38,7 +38,7 @@ public class OpenApiEnumValuesDescriptionExtension : IOpenApiExtension
     public void Write(IOpenApiWriter writer, OpenApiSpecVersion specVersion)
     {
         if (writer is null) throw new ArgumentNullException(nameof(writer));
-        if ((specVersion == OpenApiSpecVersion.OpenApi2_0 || specVersion == OpenApiSpecVersion.OpenApi3_0) &&
+        if (specVersion is OpenApiSpecVersion.OpenApi2_0 or OpenApiSpecVersion.OpenApi3_0 &&
             !string.IsNullOrEmpty(EnumName) &&
             ValuesDescriptions.Any())
         { // when we upgrade to 3.1, we don't need to write this extension as JSON schema will support writing enum values

test/Microsoft.OpenApi.Tests/Writers/OpenApiWriterAnyExtensionsTests.cs

@@ -274,7 +274,7 @@ private static string WriteAsJson(IOpenApiAny any, bool produceTerseOutput = fal
             // Act
             var value = new StreamReader(stream).ReadToEnd();
 
-            if (any.AnyType == AnyType.Primitive || any.AnyType == AnyType.Null)
+            if (any.AnyType is AnyType.Primitive or AnyType.Null)
             {
                 return value;
             }