removed some new lang features to support net6.0 and net7.0

Railway/Ensure.cs

@@ -60,6 +60,7 @@ public readonly struct Ensure<T>
         Value = value;
         ValueExpression = valueExpression;
         State = ResultState.Success;
+        Error = default;
     }
 
     internal Ensure(Error error, string valueExpression)
@@ -72,7 +73,12 @@ public readonly struct Ensure<T>
 }
 
 [Serializable]
-public class EnsureNotInitializedException(string variableName = "this") : InvalidOperationException("Ensure was not properly initialized.")
+public class EnsureNotInitializedException : InvalidOperationException
 {
-    public string VariableName { get; } = variableName;
+    public EnsureNotInitializedException(string variableName = "this")
+        : base("Ensure was not properly initialized.")
+    {
+        VariableName = variableName;
+    }
+    public string VariableName { get; }
 }

Railway/Error.cs

@@ -52,7 +52,7 @@ public abstract class Error : IEquatable<Error>, IComparable<Error>
     [Pure, MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Error Many(Error error1, Error error2) => (error1, error2) switch
     {
-        (null, null) => new ManyErrors([]),
+        (null, null) => new ManyErrors(new List<Error>()),
         (Error err, null) => err,
         (Error err, { IsEmpty: true }) => err,
         (null, Error err) => err,
@@ -231,7 +231,7 @@ public sealed class ExceptionalError : Error
             var valueString = value.ToString();
             if (string.IsNullOrEmpty(keyString) || string.IsNullOrEmpty(valueString)) continue;
 
-            values ??= [];
+            values ??= new List<KeyValuePair<string, string>>(4);
             values.Add(new(keyString, valueString));
         }
         return values?.ToImmutableDictionary() ?? ImmutableDictionary<string, string>.Empty;
@@ -377,7 +377,11 @@ public sealed class ManyErrors : Error, IEnumerable<Error>, IReadOnlyList<Error>
 }
 
 [Serializable]
-public sealed class ErrorException(string type, string message) : Exception(message)
+public sealed class ErrorException : Exception
 {
-    public string Type { get; } = type ?? nameof(ErrorException);
+    public ErrorException(string type, string message) : base(message)
+    {
+        Type = type ?? nameof(ErrorException);
+    }
+    public string Type { get; }
 }

Railway/ErrorJsonConverter.cs

@@ -35,7 +35,7 @@ public sealed class ErrorJsonConverter : JsonConverter<Error>
 
     internal static ManyErrors ReadMany(ref Utf8JsonReader reader)
     {
-        List<Error> errors = [];
+        List<Error> errors = new(4);
         while (reader.Read())
         {
             if (reader.TokenType == JsonTokenType.StartObject)
@@ -83,7 +83,7 @@ public sealed class ErrorJsonConverter : JsonConverter<Error>
                     }
                     else if (!string.IsNullOrEmpty(propname))
                     {
-                        extensionData ??= [];
+                        extensionData ??= new(4);
                         extensionData.Add(new(propname, propvalue));
                     }
 

Railway/Railway.csproj

@@ -1,7 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFrameworks>net6.0;net7.0;net8.0</TargetFrameworks>
+    <LangVersion>10.0</LangVersion>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <AssemblyName>Just.Railway</AssemblyName>
@@ -13,7 +14,6 @@
     <Copyright>Copyright (c) 2023 JustFixMe</Copyright>
     <PackageLicenseFile>LICENSE</PackageLicenseFile>
     <PackageReadmeFile>README.md</PackageReadmeFile>
-
     <RepositoryUrl>https://github.com/JustFixMe/Just.Railway/</RepositoryUrl>
     
     <EmitCompilerGeneratedFiles Condition="'$(Configuration)'=='Debug'">true</EmitCompilerGeneratedFiles>

Railway/ReflectionHelper.cs

@@ -10,58 +10,58 @@ internal static class ReflectionHelper
 
     [Pure, MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static int Compare<T>(T? left, T? right) => TypeReflectionCache<T>.CompareFunc(left, right);
-}
 
-file static class TypeReflectionCache<T>
-{
-    public static readonly Func<T?, T?, bool> IsEqualFunc;
-    public static readonly Func<T?, T?, int> CompareFunc;
-
-    static TypeReflectionCache()
+    private static class TypeReflectionCache<T>
     {
-        var type = typeof(T);
-        var isNullableStruct = type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>);
-        var underlyingType = isNullableStruct ? type.GenericTypeArguments.First() : type;
-        var thisType = typeof(TypeReflectionCache<T>);
+        public static readonly Func<T?, T?, bool> IsEqualFunc;
+        public static readonly Func<T?, T?, int> CompareFunc;
 
-        var equatableType = typeof(IEquatable<>).MakeGenericType(underlyingType);
-        if (equatableType.IsAssignableFrom(underlyingType))
+        static TypeReflectionCache()
         {
-            var isEqualFunc = thisType.GetMethod(isNullableStruct ? nameof(IsEqualNullable) : nameof(IsEqual), BindingFlags.Static | BindingFlags.Public)
-                !.MakeGenericMethod(underlyingType);
+            var type = typeof(T);
+            var isNullableStruct = type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>);
+            var underlyingType = isNullableStruct ? type.GenericTypeArguments.First() : type;
+            var thisType = typeof(TypeReflectionCache<T>);
 
-            IsEqualFunc = (Func<T?, T?, bool>)Delegate.CreateDelegate(typeof(Func<T?, T?, bool>), isEqualFunc);
-        }
-        else
-        {
-            IsEqualFunc = static (left, right) => left is null ? right is null : left.Equals(right);
+            var equatableType = typeof(IEquatable<>).MakeGenericType(underlyingType);
+            if (equatableType.IsAssignableFrom(underlyingType))
+            {
+                var isEqualFunc = thisType.GetMethod(isNullableStruct ? nameof(IsEqualNullable) : nameof(IsEqual), BindingFlags.Static | BindingFlags.Public)
+                    !.MakeGenericMethod(underlyingType);
+
+                IsEqualFunc = (Func<T?, T?, bool>)Delegate.CreateDelegate(typeof(Func<T?, T?, bool>), isEqualFunc);
+            }
+            else
+            {
+                IsEqualFunc = static (left, right) => left is null ? right is null : left.Equals(right);
+            }
+
+            var comparableType = typeof(IComparable<>).MakeGenericType(underlyingType);
+            if (comparableType.IsAssignableFrom(underlyingType))
+            {
+                var compareFunc = thisType.GetMethod(isNullableStruct ? nameof(CompareNullable) : nameof(Compare), BindingFlags.Static | BindingFlags.Public)
+                    !.MakeGenericMethod(underlyingType);
+
+                CompareFunc = (Func<T?, T?, int>)Delegate.CreateDelegate(typeof(Func<T?, T?, int>), compareFunc);
+            }
+            else
+            {
+                CompareFunc = static (left, right) => left is null
+                    ? right is null ? 0 : -1
+                    : right is null ? 1 : left.GetHashCode().CompareTo(right.GetHashCode());
+            }
         }
 
-        var comparableType = typeof(IComparable<>).MakeGenericType(underlyingType);
-        if (comparableType.IsAssignableFrom(underlyingType))
-        {
-            var compareFunc = thisType.GetMethod(isNullableStruct ? nameof(CompareNullable) : nameof(Compare), BindingFlags.Static | BindingFlags.Public)
-                !.MakeGenericMethod(underlyingType);
+    #pragma warning disable CS8604 // Possible null reference argument.
+        [Pure] public static bool IsEqual<R>(R? left, R? right) where R : notnull, IEquatable<R>, T => left is null ? right is null : left.Equals(right);
+        [Pure] public static bool IsEqualNullable<R>(R? left, R? right) where R : struct, IEquatable<R> => left is null ? right is null : right is not null && left.Value.Equals(right.Value);
 
-            CompareFunc = (Func<T?, T?, int>)Delegate.CreateDelegate(typeof(Func<T?, T?, int>), compareFunc);
-        }
-        else
-        {
-            CompareFunc = static (left, right) => left is null
-                ? right is null ? 0 : -1
-                : right is null ? 1 : left.GetHashCode().CompareTo(right.GetHashCode());
-        }
+        [Pure] public static int Compare<R>(R? left, R? right) where R : notnull, IComparable<R>, T => left is null
+            ? right is null ? 0 : -1
+            : right is null ? 1 : left.CompareTo(right);
+        [Pure] public static int CompareNullable<R>(R? left, R? right) where R : struct, IComparable<R> => left is null
+            ? right is null ? 0 : -1
+            : right is null ? 1 : left.Value.CompareTo(right.Value);
+    #pragma warning restore CS8604 // Possible null reference argument.
     }
-
-#pragma warning disable CS8604 // Possible null reference argument.
-    [Pure] public static bool IsEqual<R>(R? left, R? right) where R : notnull, IEquatable<R>, T => left is null ? right is null : left.Equals(right);
-    [Pure] public static bool IsEqualNullable<R>(R? left, R? right) where R : struct, IEquatable<R> => left is null ? right is null : right is not null && left.Value.Equals(right.Value);
-
-    [Pure] public static int Compare<R>(R? left, R? right) where R : notnull, IComparable<R>, T => left is null
-        ? right is null ? 0 : -1
-        : right is null ? 1 : left.CompareTo(right);
-    [Pure] public static int CompareNullable<R>(R? left, R? right) where R : struct, IComparable<R> => left is null
-        ? right is null ? 0 : -1
-        : right is null ? 1 : left.Value.CompareTo(right.Value);
-#pragma warning restore CS8604 // Possible null reference argument.
 }

Railway/Result.cs

@@ -136,6 +136,7 @@ public readonly struct Result<T> : IEquatable<Result<T>>
     {
         Value = value;
         State = ResultState.Success;
+        Error = default;
     }
 
     [Pure] public static explicit operator Result(Result<T> result) => result.State switch
@@ -263,7 +264,12 @@ public readonly struct SuccessUnit : IEquatable<SuccessUnit>
 }
 
 [Serializable]
-public class ResultNotInitializedException(string variableName = "this") : InvalidOperationException("Result was not properly initialized.")
+public class ResultNotInitializedException : InvalidOperationException
 {
-    public string VariableName { get; } = variableName;
+    public ResultNotInitializedException(string variableName = "this")
+        : base("Result was not properly initialized.")
+    {
+        VariableName = variableName;
+    }
+    public string VariableName { get; }
 }

Railway/ResultExtensions.cs

@@ -89,7 +89,7 @@ public static partial class ResultExtensions
             {
                 case ResultState.Error:
                     hasErrors = true;
-                    errors ??= [];
+                    errors ??= new(4);
                     errors.Add(result.Error!);
                     break;
 
@@ -123,13 +123,13 @@ public static partial class ResultExtensions
             {
                 case ResultState.Error:
                     hasErrors = true;
-                    errors ??= [];
+                    errors ??= new(4);
                     errors.Add(result.Error!);
                     break;
 
                 case ResultState.Success:
                     if (hasErrors) goto afterLoop;
-                    values ??= [];
+                    values ??= new(4);
                     values.Add(result.Value);
                     break;