diff --git a/src/Directory.Build.props b/Directory.Build.props
similarity index 61%
rename from src/Directory.Build.props
rename to Directory.Build.props
index 7f5dc43..3bcb120 100644
--- a/src/Directory.Build.props
+++ b/Directory.Build.props
@@ -21,4 +21,22 @@
 
   </PropertyGroup>
 
+  <PropertyGroup Label="Analysis rules">
+
+    <AnalysisLevel>latest-Recommended</AnalysisLevel>
+
+    <!-- Prefix generic type parameter name with 'T'  -->
+    <NoWarn>$(NoWarn);CA1715;</NoWarn>
+
+    <!-- Do not declare visible instance fields  -->
+    <NoWarn>$(NoWarn);CA1051;</NoWarn>
+
+    <!-- Identifier contains type name  -->
+    <NoWarn>$(NoWarn);CA1720;</NoWarn>
+
+    <!-- Identifiers should not match keywords  -->
+    <NoWarn>$(NoWarn);CA1716;</NoWarn>
+
+  </PropertyGroup>
+
 </Project>
diff --git a/Parlot.sln b/Parlot.sln
index df1f156..9dec130 100644
--- a/Parlot.sln
+++ b/Parlot.sln
@@ -21,6 +21,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		NuGet.config = NuGet.config
 		.github\workflows\publish.yml = .github\workflows\publish.yml
 		README.md = README.md
+		Directory.Build.props = Directory.Build.props
 	EndProjectSection
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Samples", "src\Samples\Samples.csproj", "{B9A796FE-4BEB-499A-B506-25F20C749527}"
diff --git a/src/Parlot/Compilation/CompilationContext.cs b/src/Parlot/Compilation/CompilationContext.cs
index ef44827..269f657 100644
--- a/src/Parlot/Compilation/CompilationContext.cs
+++ b/src/Parlot/Compilation/CompilationContext.cs
@@ -10,7 +10,7 @@ namespace Parlot.Compilation
     /// </summary>
     public class CompilationContext
     {
-        private int _number = 0;
+        private int _number;
 
         public CompilationContext()
         {
@@ -51,7 +51,7 @@ public CompilationContext()
         /// When set to false, the compiled statements don't need to record and define the <see cref="CompilationResult.Value"/> property.
         /// This is done to optimize compiled parser that are usually used for pattern matching only.
         /// </remarks>
-        public bool DiscardResult { get; set; } = false;
+        public bool DiscardResult { get; set; }
 
         /// <summary>
         /// Creates a <see cref="CompilationResult"/> instance with a <see cref="CompilationResult.Value"/> and <see cref="CompilationResult.Success"/>
diff --git a/src/Parlot/Compilation/ExpressionHelper.cs b/src/Parlot/Compilation/ExpressionHelper.cs
index 6ccc165..0793a2e 100644
--- a/src/Parlot/Compilation/ExpressionHelper.cs
+++ b/src/Parlot/Compilation/ExpressionHelper.cs
@@ -30,14 +30,14 @@ public static class ExpressionHelper
 
         internal static readonly ConstructorInfo Exception_ToString = typeof(Exception).GetConstructor([typeof(string)])!;
 
-        internal static ConstructorInfo TextSpan_Constructor = typeof(TextSpan).GetConstructor([typeof(string), typeof(int), typeof(int)])!;
+        internal static readonly ConstructorInfo TextSpan_Constructor = typeof(TextSpan).GetConstructor([typeof(string), typeof(int), typeof(int)])!;
 
-        internal static MethodInfo MemoryExtensions_AsSpan = typeof(MemoryExtensions).GetMethod(nameof(MemoryExtensions.AsSpan), [typeof(string)])!;
+        internal static readonly MethodInfo MemoryExtensions_AsSpan = typeof(MemoryExtensions).GetMethod(nameof(MemoryExtensions.AsSpan), [typeof(string)])!;
 
         public static Expression ArrayEmpty<T>() => ((Expression<Func<object>>)(() => Array.Empty<T>())).Body;
         public static Expression New<T>() where T : new() => ((Expression<Func<T>>)(() => new T())).Body;
         
-        public static Expression<Func<Cursor, char, char, bool>> CharacterIsInRange = (cursor,b,c) => Character.IsInRange(cursor.Current, b, c);
+        public static readonly Expression<Func<Cursor, char, char, bool>> CharacterIsInRange = (cursor,b,c) => Character.IsInRange(cursor.Current, b, c);
 
         //public static Expression NewOptionalResult<T>(this CompilationContext _, Expression hasValue, Expression value) => Expression.New(GetOptionalResult_Constructor<T>(), [hasValue, value]);
         public static Expression NewTextSpan(this CompilationContext _, Expression buffer, Expression offset, Expression count) => Expression.New(TextSpan_Constructor, [buffer, offset, count]);
diff --git a/src/Parlot/Fluent/CharLiteral.cs b/src/Parlot/Fluent/CharLiteral.cs
index 5f22ac8..4f05399 100644
--- a/src/Parlot/Fluent/CharLiteral.cs
+++ b/src/Parlot/Fluent/CharLiteral.cs
@@ -18,7 +18,7 @@ public CharLiteral(char c)
 
         public char[] ExpectedChars { get; }
 
-        public bool SkipWhitespace { get; } = false;
+        public bool SkipWhitespace { get; }
 
         public override bool Parse(ParseContext context, ref ParseResult<char> result)
         {
diff --git a/src/Parlot/Fluent/Deferred.cs b/src/Parlot/Fluent/Deferred.cs
index ee6a7b7..b5e387b 100644
--- a/src/Parlot/Fluent/Deferred.cs
+++ b/src/Parlot/Fluent/Deferred.cs
@@ -22,16 +22,16 @@ public override bool Parse(ParseContext context, ref ParseResult<T> result)
         {
             if (Parser is null)
             {
-                throw new ArgumentNullException(nameof(Parser));
+                throw new InvalidOperationException("Parser has not been initialized");
             }
 
             return Parser.Parse(context, ref result);
         }
 
-        private bool _initialized = false;
+        private bool _initialized;
         private readonly Closure _closure = new();
 
-        private class Closure
+        private sealed class Closure
         {
             public object? Func;
         }
diff --git a/src/Parlot/Fluent/NumberLiteral.cs b/src/Parlot/Fluent/NumberLiteral.cs
index 9b21990..0bc9389 100644
--- a/src/Parlot/Fluent/NumberLiteral.cs
+++ b/src/Parlot/Fluent/NumberLiteral.cs
@@ -30,7 +30,7 @@ public sealed class NumberLiteral<T> : Parser<T>, ICompilable, ISeekable
 
         public char[] ExpectedChars { get; }
 
-        public bool SkipWhitespace { get; } = false;
+        public bool SkipWhitespace { get; }
 
         public NumberLiteral(NumberOptions numberOptions = NumberOptions.Number, char decimalSeparator = DefaultDecimalSeparator, char groupSeparator = DefaultGroupSeparator)
         {
diff --git a/src/Parlot/Fluent/OneOf.cs b/src/Parlot/Fluent/OneOf.cs
index a1040f9..e02bf3e 100644
--- a/src/Parlot/Fluent/OneOf.cs
+++ b/src/Parlot/Fluent/OneOf.cs
@@ -14,7 +14,7 @@ namespace Parlot.Fluent
     /// <typeparam name="T"></typeparam>
     public sealed class OneOf<T> : Parser<T>, ICompilable, ISeekable
     {
-        internal readonly Parser<T>[] _parsers;
+        private readonly Parser<T>[] _parsers;
         internal readonly CharMap<List<Parser<T>>>? _map;
 
         public OneOf(Parser<T>[] parsers)
diff --git a/src/Parlot/Fluent/ParseContext.cs b/src/Parlot/Fluent/ParseContext.cs
index 00122fa..47de5c5 100644
--- a/src/Parlot/Fluent/ParseContext.cs
+++ b/src/Parlot/Fluent/ParseContext.cs
@@ -4,7 +4,9 @@ namespace Parlot.Fluent
 {
     public class ParseContext
     {
-        public static int DefaultCompilationThreshold = 0;
+#pragma warning disable CA2211 // Non-constant fields should not be visible
+        public static int DefaultCompilationThreshold;
+#pragma warning restore CA2211
 
         /// <summary>
         /// The number of usages of the parser before it is compiled automatically. <c>0</c> to disable automatic compilation. Default is 0.
diff --git a/src/Parlot/Fluent/Parser.TryParse.cs b/src/Parlot/Fluent/Parser.TryParse.cs
index 502a294..9c76d60 100644
--- a/src/Parlot/Fluent/Parser.TryParse.cs
+++ b/src/Parlot/Fluent/Parser.TryParse.cs
@@ -4,7 +4,7 @@
 
     public abstract partial class Parser<T>
     {
-        private int _invocations = 0;
+        private int _invocations;
         private volatile Parser<T>? _compiledParser;
 
         public T? Parse(string text)
diff --git a/src/Parlot/Fluent/Parsers.cs b/src/Parlot/Fluent/Parsers.cs
index cfe73ee..7d88440 100644
--- a/src/Parlot/Fluent/Parsers.cs
+++ b/src/Parlot/Fluent/Parsers.cs
@@ -2,6 +2,8 @@
 using System.Collections.Generic;
 using System.Numerics;
 
+#pragma warning disable CA1822 // Mark members as static
+
 namespace Parlot.Fluent
 {
     public static partial class Parsers
diff --git a/src/Parlot/Fluent/Sequence.cs b/src/Parlot/Fluent/Sequence.cs
index deca64e..c1dfc32 100644
--- a/src/Parlot/Fluent/Sequence.cs
+++ b/src/Parlot/Fluent/Sequence.cs
@@ -7,8 +7,8 @@ namespace Parlot.Fluent
 {
     public sealed class Sequence<T1, T2> : Parser<ValueTuple<T1, T2>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
-        internal readonly Parser<T1> _parser1;
-        internal readonly Parser<T2> _parser2;
+        private readonly Parser<T1> _parser1;
+        private readonly Parser<T2> _parser2;
         public Sequence(Parser<T1> parser1, Parser<T2> parser2)
         {
             _parser1 = parser1 ?? throw new ArgumentNullException(nameof(parser1));
@@ -70,7 +70,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class Sequence<T1, T2, T3> : Parser<ValueTuple<T1, T2, T3>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2>> _parser;
-        internal readonly Parser<T3> _lastParser;
+        private readonly Parser<T3> _lastParser;
 
         public Sequence(Parser<ValueTuple<T1, T2>> 
             parser,
@@ -143,7 +143,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class Sequence<T1, T2, T3, T4> : Parser<ValueTuple<T1, T2, T3, T4>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3>> _parser;
-        internal readonly Parser<T4> _lastParser;
+        private readonly Parser<T4> _lastParser;
 
         public Sequence(Parser<ValueTuple<T1, T2, T3>> parser, Parser<T4> lastParser)
         {
@@ -214,7 +214,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class Sequence<T1, T2, T3, T4, T5> : Parser<ValueTuple<T1, T2, T3, T4, T5>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4>> _parser;
-        internal readonly Parser<T5> _lastParser;
+        private readonly Parser<T5> _lastParser;
         
         public Sequence(Parser<ValueTuple<T1, T2, T3, T4>> parser, Parser<T5> lastParser)
         {
@@ -286,7 +286,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class Sequence<T1, T2, T3, T4, T5, T6> : Parser<ValueTuple<T1, T2, T3, T4, T5, T6>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4, T5>> _parser;
-        internal readonly Parser<T6> _lastParser;        
+        private readonly Parser<T6> _lastParser;        
 
         public Sequence(Parser<ValueTuple<T1, T2, T3, T4, T5>> parser, Parser<T6> lastParser)
         {
@@ -360,7 +360,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class Sequence<T1, T2, T3, T4, T5, T6, T7> : Parser<ValueTuple<T1, T2, T3, T4, T5, T6, T7>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4, T5, T6>> _parser;
-        internal readonly Parser<T7> _lastParser;
+        private readonly Parser<T7> _lastParser;
 
         public Sequence(Parser<ValueTuple<T1, T2, T3, T4, T5, T6>> parser, Parser<T7> lastParser)
         {
diff --git a/src/Parlot/Fluent/SequenceAndSkip.cs b/src/Parlot/Fluent/SequenceAndSkip.cs
index 55423d7..2238455 100644
--- a/src/Parlot/Fluent/SequenceAndSkip.cs
+++ b/src/Parlot/Fluent/SequenceAndSkip.cs
@@ -8,8 +8,8 @@ namespace Parlot.Fluent
 {
     public sealed class SequenceAndSkip<T1, T2> : Parser<T1>, ICompilable, ISkippableSequenceParser, ISeekable
     {
-        internal readonly Parser<T1> _parser1;
-        internal readonly Parser<T2> _parser2;
+        private readonly Parser<T1> _parser1;
+        private readonly Parser<T2> _parser2;
 
         public SequenceAndSkip(Parser<T1> parser1, Parser<T2> parser2)
         {
@@ -129,7 +129,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceAndSkip<T1, T2, T3> : Parser<ValueTuple<T1, T2>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2>> _parser;
-        internal readonly Parser<T3> _lastParser;
+        private readonly Parser<T3> _lastParser;
 
         public SequenceAndSkip(Parser<ValueTuple<T1, T2>>
             parser,
@@ -201,7 +201,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceAndSkip<T1, T2, T3, T4> : Parser<ValueTuple<T1, T2, T3>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3>> _parser;
-        internal readonly Parser<T4> _lastParser;
+        private readonly Parser<T4> _lastParser;
 
         public SequenceAndSkip(Parser<ValueTuple<T1, T2, T3>> parser, Parser<T4> lastParser)
         {
@@ -271,7 +271,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceAndSkip<T1, T2, T3, T4, T5> : Parser<ValueTuple<T1, T2, T3, T4>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4>> _parser;
-        internal readonly Parser<T5> _lastParser;
+        private readonly Parser<T5> _lastParser;
         
         public SequenceAndSkip(Parser<ValueTuple<T1, T2, T3, T4>> parser, Parser<T5> lastParser)
         {
@@ -342,7 +342,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceAndSkip<T1, T2, T3, T4, T5, T6> : Parser<ValueTuple<T1, T2, T3, T4, T5>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4, T5>> _parser;
-        internal readonly Parser<T6> _lastParser;        
+        private readonly Parser<T6> _lastParser;        
 
         public SequenceAndSkip(Parser<ValueTuple<T1, T2, T3, T4, T5>> parser, Parser<T6> lastParser)
         {
@@ -416,7 +416,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceAndSkip<T1, T2, T3, T4, T5, T6, T7> : Parser<ValueTuple<T1, T2, T3, T4, T5, T6>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4, T5, T6>> _parser;
-        internal readonly Parser<T7> _lastParser;
+        private readonly Parser<T7> _lastParser;
 
         public SequenceAndSkip(Parser<ValueTuple<T1, T2, T3, T4, T5, T6>> parser, Parser<T7> lastParser)
         {
@@ -491,7 +491,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceAndSkip<T1, T2, T3, T4, T5, T6, T7, T8> : Parser<ValueTuple<T1, T2, T3, T4, T5, T6, T7>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4, T5, T6, T7>> _parser;
-        internal readonly Parser<T8> _lastParser;
+        private readonly Parser<T8> _lastParser;
 
         public SequenceAndSkip(Parser<ValueTuple<T1, T2, T3, T4, T5, T6, T7>> parser, Parser<T8> lastParser)
         {
diff --git a/src/Parlot/Fluent/SequenceSkipAnd.cs b/src/Parlot/Fluent/SequenceSkipAnd.cs
index f2d1135..a4e1de7 100644
--- a/src/Parlot/Fluent/SequenceSkipAnd.cs
+++ b/src/Parlot/Fluent/SequenceSkipAnd.cs
@@ -8,8 +8,8 @@ namespace Parlot.Fluent
 {
     public sealed class SequenceSkipAnd<T1, T2> : Parser<T2>, ICompilable, ISkippableSequenceParser, ISeekable
     {
-        internal readonly Parser<T1> _parser1;
-        internal readonly Parser<T2> _parser2;
+        private readonly Parser<T1> _parser1;
+        private readonly Parser<T2> _parser2;
 
         public SequenceSkipAnd(Parser<T1> parser1, Parser<T2> parser2)
         {
@@ -129,7 +129,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceSkipAnd<T1, T2, T3> : Parser<ValueTuple<T1, T3>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2>> _parser;
-        internal readonly Parser<T3> _lastParser;
+        private readonly Parser<T3> _lastParser;
 
         public SequenceSkipAnd(Parser<ValueTuple<T1, T2>>
             parser,
@@ -204,7 +204,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceSkipAnd<T1, T2, T3, T4> : Parser<ValueTuple<T1, T2, T4>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3>> _parser;
-        internal readonly Parser<T4> _lastParser;
+        private readonly Parser<T4> _lastParser;
 
         public SequenceSkipAnd(Parser<ValueTuple<T1, T2, T3>> parser, Parser<T4> lastParser)
         {
@@ -277,7 +277,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceSkipAnd<T1, T2, T3, T4, T5> : Parser<ValueTuple<T1, T2, T3, T5>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4>> _parser;
-        internal readonly Parser<T5> _lastParser;
+        private readonly Parser<T5> _lastParser;
         
         public SequenceSkipAnd(Parser<ValueTuple<T1, T2, T3, T4>> parser, Parser<T5> lastParser)
         {
@@ -351,7 +351,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceSkipAnd<T1, T2, T3, T4, T5, T6> : Parser<ValueTuple<T1, T2, T3, T4, T6>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4, T5>> _parser;
-        internal readonly Parser<T6> _lastParser;        
+        private readonly Parser<T6> _lastParser;        
 
         public SequenceSkipAnd(Parser<ValueTuple<T1, T2, T3, T4, T5>> parser, Parser<T6> lastParser)
         {
@@ -427,7 +427,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceSkipAnd<T1, T2, T3, T4, T5, T6, T7> : Parser<ValueTuple<T1, T2, T3, T4, T5, T7>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4, T5, T6>> _parser;
-        internal readonly Parser<T7> _lastParser;
+        private readonly Parser<T7> _lastParser;
 
         public SequenceSkipAnd(Parser<ValueTuple<T1, T2, T3, T4, T5, T6>> parser, Parser<T7> lastParser)
         {
@@ -504,7 +504,7 @@ public CompilationResult Compile(CompilationContext context)
     public sealed class SequenceSkipAnd<T1, T2, T3, T4, T5, T6, T7, T8> : Parser<ValueTuple<T1, T2, T3, T4, T5, T6, T8>>, ICompilable, ISkippableSequenceParser, ISeekable
     {
         private readonly Parser<ValueTuple<T1, T2, T3, T4, T5, T6, T7>> _parser;
-        internal readonly Parser<T8> _lastParser;
+        private readonly Parser<T8> _lastParser;
 
         public SequenceSkipAnd(Parser<ValueTuple<T1, T2, T3, T4, T5, T6, T7>> parser, Parser<T8> lastParser)
         {
diff --git a/src/Parlot/Fluent/StringLiteral.cs b/src/Parlot/Fluent/StringLiteral.cs
index 84e0522..4e4dcd2 100644
--- a/src/Parlot/Fluent/StringLiteral.cs
+++ b/src/Parlot/Fluent/StringLiteral.cs
@@ -40,7 +40,7 @@ public StringLiteral(StringLiteralQuotes quotes)
 
         public char[] ExpectedChars { get; }
 
-        public bool SkipWhitespace { get; } = false;
+        public bool SkipWhitespace { get; }
 
         public override bool Parse(ParseContext context, ref ParseResult<TextSpan> result)
         {
diff --git a/src/Parlot/Fluent/TextLiteral.cs b/src/Parlot/Fluent/TextLiteral.cs
index b3236b4..dd4518a 100644
--- a/src/Parlot/Fluent/TextLiteral.cs
+++ b/src/Parlot/Fluent/TextLiteral.cs
@@ -6,6 +6,8 @@
 
 namespace Parlot.Fluent
 {
+    using System.Globalization;
+
     public sealed class TextLiteral : Parser<string>, ICompilable, ISeekable
     {
         private readonly StringComparison _comparisonType;
@@ -40,7 +42,7 @@ public TextLiteral(string text, StringComparison comparisonType)
                 }
                 else
                 {
-                    ExpectedChars = ignoreCase ? [Text.ToUpper()[0], Text.ToLower()[0]] : [Text[0]];
+                    ExpectedChars = ignoreCase ? [Text.ToUpper(CultureInfo.CurrentCulture)[0], Text.ToLower(CultureInfo.CurrentCulture)[0]] : [Text[0]];
                 }
             }
         }
@@ -51,7 +53,7 @@ public TextLiteral(string text, StringComparison comparisonType)
 
         public char[] ExpectedChars { get; } = [];
 
-        public bool SkipWhitespace { get; } = false;
+        public bool SkipWhitespace { get; }
 
         public override bool Parse(ParseContext context, ref ParseResult<string> result)
         {
diff --git a/src/Parlot/Fluent/Then.cs b/src/Parlot/Fluent/Then.cs
index 97bd94c..71a22d3 100644
--- a/src/Parlot/Fluent/Then.cs
+++ b/src/Parlot/Fluent/Then.cs
@@ -16,7 +16,7 @@ public sealed class Then<T, U> : Parser<U>, ICompilable, ISeekable
     {
         private readonly Func<T, U>? _action1;
         private readonly Func<ParseContext, T, U>? _action2;
-        private readonly U? _value = default;
+        private readonly U? _value;
         private readonly Parser<T> _parser;
 
         private Then(Parser<T> parser)
diff --git a/test/Parlot.Benchmarks/Parlot.Benchmarks.csproj b/test/Parlot.Benchmarks/Parlot.Benchmarks.csproj
index a6ac86a..9e96f75 100644
--- a/test/Parlot.Benchmarks/Parlot.Benchmarks.csproj
+++ b/test/Parlot.Benchmarks/Parlot.Benchmarks.csproj
@@ -4,6 +4,7 @@
     <OutputType>Exe</OutputType>
     <TargetFrameworks>net6.0;net8.0</TargetFrameworks>
     <IsPackable>false</IsPackable>
+    <AnalysisLevel>latest-Default</AnalysisLevel>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/test/Parlot.Tests/Parlot.Tests.csproj b/test/Parlot.Tests/Parlot.Tests.csproj
index 6b39515..a4b1ff7 100644
--- a/test/Parlot.Tests/Parlot.Tests.csproj
+++ b/test/Parlot.Tests/Parlot.Tests.csproj
@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetFrameworks>net6.0;net8.0</TargetFrameworks>
     <IsPackable>false</IsPackable>
-    <LangVersion>latest</LangVersion>
+    <AnalysisLevel>latest-Default</AnalysisLevel>
   </PropertyGroup>
 
   <ItemGroup>