Fix analyzer warnings on NET 9 SDK

YamlDotNet.Benchmark/YamlDotNet.Benchmark.csproj

@@ -5,7 +5,6 @@
         <TargetFrameworks>net8.0;net47</TargetFrameworks>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
-        <LangVersion>10.0</LangVersion>
     </PropertyGroup>
 
     <ItemGroup>

YamlDotNet/Core/AnchorName.cs

@@ -24,7 +24,7 @@
 
 namespace YamlDotNet.Core
 {
-    public struct AnchorName : IEquatable<AnchorName>
+    public readonly struct AnchorName : IEquatable<AnchorName>
     {
         public static readonly AnchorName Empty;
 

YamlDotNet/Core/Emitter.cs

@@ -41,7 +41,7 @@ public class Emitter : IEmitter
         private static readonly Regex UriReplacer = new Regex(@"[^0-9A-Za-z_\-;?@=$~\\\)\]/:&+,\.\*\(\[!]",
             StandardRegexOptions.Compiled | RegexOptions.Singleline);
 
-        private static readonly string[] newLineSeparators = new[] { "\r\n", "\r", "\n" };
+        private static readonly string[] NewLineSeparators = ["\r\n", "\r", "\n"];
 
         private readonly TextWriter output;
         private readonly bool outputUsesUnicodeEncoding;
@@ -653,7 +653,7 @@ private void EmitComment(Comment comment)
                 return;
             }
 
-            var lines = comment.Value.Split(newLineSeparators, StringSplitOptions.None);
+            var lines = comment.Value.Split(NewLineSeparators, StringSplitOptions.None);
 
             if (comment.IsInline)
             {

YamlDotNet/Core/InsertionQueue.cs

@@ -39,7 +39,9 @@ public sealed class InsertionQueue<T> : IEnumerable<T>
         private int readPtr;
         private int writePtr;
         private int mask;
+#pragma warning disable IDE0032
         private int count;
+#pragma warning restore IDE0032
 
         public InsertionQueue(int initialCapacity = DefaultInitialCapacity)
         {

YamlDotNet/Core/MergingParser.cs

@@ -162,7 +162,7 @@ private IEnumerable<ParsingEvent> GetMappingEvents(AnchorName anchor)
             return events.FromAnchor(anchor).Where(e => !this.events.IsDeleted(e))
                 .Select(e => e.Value)
                 .TakeWhile(e => (nesting += e.NestingIncrease) >= 0)
-                .Select(e => cloner.Clone(e));
+                .Select(cloner.Clone);
         }
 
         private sealed class ParsingEventCollection : IEnumerable<LinkedListNode<ParsingEvent>>

YamlDotNet/Core/ParserExtensions.cs

@@ -170,7 +170,7 @@ public static bool Accept<T>(this IParser parser) where T : ParsingEvent
         /// otherwise returns false.</returns>
         public static bool TryFindMappingEntry(this IParser parser, Func<Scalar, bool> selector, [MaybeNullWhen(false)] out Scalar? key, [MaybeNullWhen(false)] out ParsingEvent? value)
         {
-            if (parser.TryConsume<MappingStart>(out var _start))
+            if (parser.TryConsume<MappingStart>(out _))
             {
                 while (parser.Current != null)
                 {

YamlDotNet/Core/Scanner.cs

@@ -67,7 +67,6 @@ public class Scanner : IScanner
         private bool streamStartProduced;
         private bool streamEndProduced;
         private bool plainScalarFollowedByComment;
-        private long flowSequenceStartLine;
         private bool flowCollectionFetched;
         private bool startFlowCollectionFetched;
         private long indent = -1;
@@ -933,7 +932,6 @@ private void FetchFlowCollectionStart(bool isSequenceToken)
             if (isSequenceToken)
             {
                 token = new FlowSequenceStart(start, start);
-                flowSequenceStartLine = token.Start.Line;
             }
             else
             {
@@ -2520,7 +2518,7 @@ private string ScanTagUri(string? head, Mark start)
             return result;
         }
 
-        private static readonly byte[] EmptyBytes = Array.Empty<byte>();
+        private static readonly byte[] EmptyBytes = [];
 
         /// <summary>
         /// Decode an URI-escape sequence corresponding to a single UTF-8 character.

YamlDotNet/Helpers/ExpressionExtensions.cs

@@ -19,8 +19,6 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#if !NET20
-
 using System;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq.Expressions;
@@ -82,4 +80,3 @@ private static TMemberInfo TryGetMemberExpression<TMemberInfo>(LambdaExpression
         }
     }
 }
-#endif

YamlDotNet/Helpers/Polyfills.cs

@@ -19,7 +19,9 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+#pragma warning disable IDE0130
 namespace YamlDotNet
+#pragma warning restore IDE0130
 {
     internal static class Polyfills
     {

YamlDotNet/ReflectionExtensions.cs

@@ -305,12 +305,13 @@ public static Attribute[] GetAllCustomAttributes<TAttribute>(this PropertyInfo m
             return Attribute.GetCustomAttributes(member, typeof(TAttribute), inherit: true);
         }
 
-        private static readonly ConcurrentDictionary<Type, bool> typesHaveNullContext = new ConcurrentDictionary<Type, bool>();
+        private static readonly ConcurrentDictionary<Type, bool> TypesHaveNullContext = new();
+
         public static bool AcceptsNull(this MemberInfo member)
         {
             var result = true; //default to allowing nulls, this will be set to false if there is a null context on the type
 #if NET8_0_OR_GREATER
-            var typeHasNullContext = typesHaveNullContext.GetOrAdd(member.DeclaringType, (Type t) =>
+            var typeHasNullContext = TypesHaveNullContext.GetOrAdd(member.DeclaringType, (Type t) =>
             {
                 var attributes = t.GetCustomAttributes(typeof(System.Runtime.CompilerServices.NullableContextAttribute), true);
                 return (attributes?.Length ?? 0) > 0;
@@ -325,7 +326,7 @@ public static bool AcceptsNull(this MemberInfo member)
 
             return result;
 #else
-            var typeHasNullContext = typesHaveNullContext.GetOrAdd(member.DeclaringType, (Type t) =>
+            var typeHasNullContext = TypesHaveNullContext.GetOrAdd(member.DeclaringType, (Type t) =>
             {
                 var attributes = t.GetCustomAttributes(true);
                 return attributes.Any(x => x.GetType().FullName == "System.Runtime.CompilerServices.NullableContextAttribute");

YamlDotNet/RepresentationModel/YamlMappingNode.cs

@@ -196,19 +196,13 @@ internal override void ResolveAliases(DocumentLoadingState state)
             {
                 if (entry.Key is YamlAliasNode)
                 {
-                    if (keysToUpdate == null)
-                    {
-                        keysToUpdate = new Dictionary<YamlNode, YamlNode>();
-                    }
+                    keysToUpdate ??= new Dictionary<YamlNode, YamlNode>();
                     // TODO: The representation model should be redesigned, because here the anchor could be null but that would be invalid YAML
                     keysToUpdate.Add(entry.Key, state.GetNode(entry.Key.Anchor!, entry.Key.Start, entry.Key.End));
                 }
                 if (entry.Value is YamlAliasNode)
                 {
-                    if (valuesToUpdate == null)
-                    {
-                        valuesToUpdate = new Dictionary<YamlNode, YamlNode>();
-                    }
+                    valuesToUpdate ??= new Dictionary<YamlNode, YamlNode>();
                     // TODO: The representation model should be redesigned, because here the anchor could be null but that would be invalid YAML
                     valuesToUpdate.Add(entry.Key, state.GetNode(entry.Value.Anchor!, entry.Value.Start, entry.Value.End));
                 }

YamlDotNet/RepresentationModel/YamlScalarNode.cs

@@ -37,28 +37,28 @@ namespace YamlDotNet.RepresentationModel
     [DebuggerDisplay("{Value}")]
     public sealed class YamlScalarNode : YamlNode, IYamlConvertible
     {
-        private bool _forceImplicitPlain;
-        private string? _value;
+        private bool forceImplicitPlain;
+        private string? value;
 
         /// <summary>
         /// Gets or sets the value of the node.
         /// </summary>
         /// <value>The value.</value>
         public string? Value
         {
-            get => _value;
+            get => value;
             set
             {
                 if (value == null)
                 {
-                    _forceImplicitPlain = true;
+                    forceImplicitPlain = true;
                 }
                 else
                 {
-                    _forceImplicitPlain = false;
+                    forceImplicitPlain = false;
                 }
 
-                _value = value;
+                this.value = value;
             }
         }
 
@@ -86,7 +86,7 @@ private void Load(IParser parser, DocumentLoadingState state)
             var value = scalar.Value;
             if (scalar.Style == ScalarStyle.Plain && Tag.IsEmpty)
             {
-                _forceImplicitPlain = value.Length switch
+                forceImplicitPlain = value.Length switch
                 {
                     // we have an implicit null value without a tag stating it, fake it out
                     0 => true,
@@ -97,7 +97,7 @@ private void Load(IParser parser, DocumentLoadingState state)
                 };
             }
 
-            _value = value;
+            this.value = value;
             Style = scalar.Style;
         }
 
@@ -136,7 +136,7 @@ internal override void Emit(IEmitter emitter, EmitterState state)
             var tag = Tag;
             var implicitPlain = tag.IsEmpty;
 
-            if (_forceImplicitPlain &&
+            if (forceImplicitPlain &&
                 Style == ScalarStyle.Plain &&
                 (Value == null || Value == ""))
             {

YamlDotNet/RepresentationModel/YamlStream.cs

@@ -31,7 +31,7 @@ namespace YamlDotNet.RepresentationModel
     /// </summary>
     public class YamlStream : IEnumerable<YamlDocument>
     {
-        private readonly IList<YamlDocument> documents = new List<YamlDocument>();
+        private readonly List<YamlDocument> documents = [];
 
         /// <summary>
         /// Gets the documents inside the stream.

YamlDotNet/Serialization/Converters/DateTime8601Converter.cs

@@ -31,7 +31,6 @@ namespace YamlDotNet.Serialization.Converters
     /// </summary>
     public class DateTime8601Converter : IYamlTypeConverter
     {
-        private readonly IFormatProvider provider;
         private readonly ScalarStyle scalarStyle;
 
         /// <summary>
@@ -47,7 +46,6 @@ public DateTime8601Converter()
         /// </summary>
         public DateTime8601Converter(ScalarStyle scalarStyle)
         {
-            this.provider = CultureInfo.InvariantCulture;
             this.scalarStyle = scalarStyle;
         }
 

YamlDotNet/Serialization/Deserializer.cs

@@ -84,17 +84,17 @@ public T Deserialize<T>(IParser parser)
 
         public object? Deserialize(string input)
         {
-            return Deserialize(input, typeof(object));
+            return Deserialize<object>(input);
         }
 
         public object? Deserialize(TextReader input)
         {
-            return Deserialize(input, typeof(object));
+            return Deserialize<object>(input);
         }
 
         public object? Deserialize(IParser parser)
         {
-            return Deserialize(parser, typeof(object));
+            return Deserialize<object>(parser);
         }
 
         public object? Deserialize(string input, Type type)

YamlDotNet/Serialization/EventEmitters/JsonEventEmitter.cs

@@ -32,7 +32,7 @@ public sealed class JsonEventEmitter : ChainedEventEmitter
         private readonly YamlFormatter formatter;
         private readonly INamingConvention enumNamingConvention;
         private readonly ITypeInspector typeInspector;
-        private static readonly Regex numericRegex = new Regex(@"^-?\d+\.?\d+$", RegexOptions.Compiled);
+        private static readonly Regex NumericRegex = new Regex(@"^-?\d+\.?\d+$", RegexOptions.Compiled);
 
         public JsonEventEmitter(IEventEmitter nextEmitter, YamlFormatter formatter, INamingConvention enumNamingConvention, ITypeInspector typeInspector)
             : base(nextEmitter)
@@ -90,7 +90,7 @@ public override void Emit(ScalarEventInfo eventInfo, IEmitter emitter)
                     case TypeCode.Decimal:
                         eventInfo.RenderedValue = formatter.FormatNumber(value);
 
-                        if (!numericRegex.IsMatch(eventInfo.RenderedValue))
+                        if (!NumericRegex.IsMatch(eventInfo.RenderedValue))
                         {
                             eventInfo.Style = ScalarStyle.DoubleQuoted;
                         }

YamlDotNet/Serialization/NodeDeserializers/DictionaryNodeDeserializer.cs

@@ -23,9 +23,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using YamlDotNet.Core;
-using YamlDotNet.Core.Events;
 using YamlDotNet.Helpers;
-using YamlDotNet.Serialization.Utilities;
 
 namespace YamlDotNet.Serialization.NodeDeserializers
 {
@@ -53,11 +51,9 @@ public bool Deserialize(IParser parser, Type expectedType, Func<IParser, Type, o
                 value = objectFactory.Create(expectedType);
 
                 dictionary = value as IDictionary;
-                if (dictionary == null)
-                {
-                    // Uncommon case where a type implements IDictionary<TKey, TValue> but not IDictionary
-                    dictionary = (IDictionary?)Activator.CreateInstance(typeof(GenericDictionaryToNonGenericAdapter<,>).MakeGenericType(keyType, valueType), value);
-                }
+
+                // Uncommon case where a type implements IDictionary<TKey, TValue> but not IDictionary
+                dictionary ??= (IDictionary?)Activator.CreateInstance(typeof(GenericDictionaryToNonGenericAdapter<,>).MakeGenericType(keyType, valueType), value);
             }
             else if (typeof(IDictionary).IsAssignableFrom(expectedType))
             {

YamlDotNet/Serialization/NodeDeserializers/ScalarNodeDeserializer.cs

@@ -142,7 +142,7 @@ public bool Deserialize(IParser parser, Type expectedType, Func<IParser, Type, o
             return true;
         }
 
-        private static object DeserializeBooleanHelper(string value)
+        private static bool DeserializeBooleanHelper(string value)
         {
             bool result;
 

YamlDotNet/Serialization/NodeDeserializers/StaticDictionaryNodeDeserializer.cs

@@ -27,26 +27,26 @@ namespace YamlDotNet.Serialization.NodeDeserializers
 {
     public class StaticDictionaryNodeDeserializer : DictionaryDeserializer, INodeDeserializer
     {
-        private readonly ObjectFactories.StaticObjectFactory _objectFactory;
+        private readonly ObjectFactories.StaticObjectFactory objectFactory;
 
         public StaticDictionaryNodeDeserializer(ObjectFactories.StaticObjectFactory objectFactory, bool duplicateKeyChecking)
             : base(duplicateKeyChecking)
         {
-            _objectFactory = objectFactory ?? throw new ArgumentNullException(nameof(objectFactory));
+            this.objectFactory = objectFactory ?? throw new ArgumentNullException(nameof(objectFactory));
         }
 
         public bool Deserialize(IParser reader, Type expectedType, Func<IParser, Type, object?> nestedObjectDeserializer, out object? value, ObjectDeserializer rootDeserializer)
         {
-            if (_objectFactory.IsDictionary(expectedType))
+            if (objectFactory.IsDictionary(expectedType))
             {
-                var result = _objectFactory.Create(expectedType) as IDictionary;
+                var result = objectFactory.Create(expectedType) as IDictionary;
                 if (result == null)
                 {
                     value = null;
                     return false;
                 }
-                var keyType = _objectFactory.GetKeyType(expectedType);
-                var valueType = _objectFactory.GetValueType(expectedType);
+                var keyType = objectFactory.GetKeyType(expectedType);
+                var valueType = objectFactory.GetValueType(expectedType);
 
                 value = result;
                 base.Deserialize(keyType, valueType, reader, nestedObjectDeserializer, result, rootDeserializer);