diff --git a/Source/Sundew.DiscriminatedUnions.Api.Generator/Sundew.DiscriminatedUnions.Api.Generator.csproj b/Source/Sundew.DiscriminatedUnions.Api.Generator/Sundew.DiscriminatedUnions.Api.Generator.csproj
index b05c3c5..1ddd3ef 100644
--- a/Source/Sundew.DiscriminatedUnions.Api.Generator/Sundew.DiscriminatedUnions.Api.Generator.csproj
+++ b/Source/Sundew.DiscriminatedUnions.Api.Generator/Sundew.DiscriminatedUnions.Api.Generator.csproj
@@ -1,9 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <CodeAnalysisRuleSet></CodeAnalysisRuleSet>
     <IsPackable>false</IsPackable>
-    <RuntimeIdentifiers>win10-x64;osx.10.12-x64;debian.8-x64</RuntimeIdentifiers>
+    <RuntimeIdentifiers>win-x64;osx-x64;linux-x64</RuntimeIdentifiers>
     <Nullable>enable</Nullable>
     <OutputType>Exe</OutputType>
     <PlatformTarget>AnyCPU</PlatformTarget>
diff --git a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/CodeAnalysisHelper.cs b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/CodeAnalysisHelper.cs
index 05194e4..19bb369 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/CodeAnalysisHelper.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/CodeAnalysisHelper.cs
@@ -16,9 +16,13 @@ namespace Sundew.DiscriminatedUnions.Generator;
 using Sundew.DiscriminatedUnions.Generator.Model;
 using Sundew.DiscriminatedUnions.Shared;
 using static Sundew.DiscriminatedUnions.Generator.OutputStage.GeneratorConstants;
+using Type = Sundew.DiscriminatedUnions.Generator.Model.Type;
 
 internal static class CodeAnalysisHelper
 {
+    private const string? OutText = "out";
+    private const string? InText = "in";
+
     private static readonly HashSet<string> Keywords = new HashSet<string>
     {
         "abstract",
@@ -172,18 +176,6 @@ public static Type GetSourceType(this ITypeSymbol typeSymbol)
 
     public static FullType GetFullType(this ITypeSymbol typeSymbol, bool useFullyQualifiedFormat = false)
     {
-        string? GetGenericQualifier(INamedTypeSymbol namedTypeSymbol)
-        {
-            var name = namedTypeSymbol.ToDisplayString(useFullyQualifiedFormat ? FullyQualifiedDisplayFormat : NameQualifiedTypeFormat);
-            var index = name.IndexOf('<');
-            if (index > -1)
-            {
-                return name.Substring(index);
-            }
-
-            return null;
-        }
-
         switch (typeSymbol)
         {
             case INamedTypeSymbol namedTypeSymbol:
@@ -195,12 +187,10 @@ public static FullType GetFullType(this ITypeSymbol typeSymbol, bool useFullyQua
                     isShortNameAlias ? string.Empty : GlobalAssemblyAlias,
                     false,
                     new TypeMetadata(
-                        !isShortNameAlias && namedTypeSymbol.IsTypeGenericWithTypeParameters()
-                            ? GetGenericQualifier(namedTypeSymbol)
-                            : null,
                         fullName,
                         namedTypeSymbol.TypeParameters.Select(x => new TypeParameter(
                             x.Name,
+                            x.Variance,
                             GetUnderlyingTypeConstraint(x)
                                 .Concat(x.ConstraintTypes.Select(x =>
                                     x.ToDisplayString(FullyQualifiedDisplayFormat)))
@@ -213,9 +203,9 @@ public static FullType GetFullType(this ITypeSymbol typeSymbol, bool useFullyQua
                     elementAttributeName,
                     elementIsShortNameAlias ? string.Empty : GlobalAssemblyAlias,
                     true,
-                    new TypeMetadata(null, elementFullName, ImmutableArray<TypeParameter>.Empty));
+                    new TypeMetadata(elementFullName, ImmutableArray<TypeParameter>.Empty));
             case ITypeParameterSymbol typeParameterSymbol:
-                return new FullType(typeParameterSymbol.MetadataName, string.Empty, string.Empty, string.Empty, false, new TypeMetadata(null, string.Empty, ImmutableArray<TypeParameter>.Empty));
+                return new FullType(typeParameterSymbol.MetadataName, string.Empty, string.Empty, string.Empty, false, new TypeMetadata(string.Empty, ImmutableArray<TypeParameter>.Empty));
             default:
                 throw new System.ArgumentOutOfRangeException(nameof(typeSymbol));
         }
diff --git a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/DeclarationStage/TypeParameter.cs b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/DeclarationStage/TypeParameter.cs
index 5e4f036..ab966cd 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/DeclarationStage/TypeParameter.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/DeclarationStage/TypeParameter.cs
@@ -7,6 +7,7 @@
 
 namespace Sundew.DiscriminatedUnions.Generator.DeclarationStage;
 
+using Microsoft.CodeAnalysis;
 using Sundew.Base.Collections.Immutable;
 
-internal readonly record struct TypeParameter(string Name, ValueArray<string> Constraints);
\ No newline at end of file
+internal readonly record struct TypeParameter(string Name, VarianceKind VarianceKind, ValueArray<string> Constraints);
\ No newline at end of file
diff --git a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/Model/TypeMetadata.cs b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/Model/TypeMetadata.cs
index 6d8394a..c1bc78f 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/Model/TypeMetadata.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/Model/TypeMetadata.cs
@@ -10,4 +10,4 @@ namespace Sundew.DiscriminatedUnions.Generator.Model;
 using Sundew.Base.Collections.Immutable;
 using Sundew.DiscriminatedUnions.Generator.DeclarationStage;
 
-internal readonly record struct TypeMetadata(string? GenericQualifier, string FullName, ValueArray<TypeParameter> TypeParameters);
\ No newline at end of file
+internal readonly record struct TypeMetadata(string FullName, ValueArray<TypeParameter> TypeParameters);
\ No newline at end of file
diff --git a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/OutputStage/DiscriminatedUnionOutputProvider.cs b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/OutputStage/DiscriminatedUnionOutputProvider.cs
index 634a29c..828c73f 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/OutputStage/DiscriminatedUnionOutputProvider.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/OutputStage/DiscriminatedUnionOutputProvider.cs
@@ -112,7 +112,7 @@ private static string GetUnionSource(in DiscriminatedUnion discriminatedUnion, s
             .Append(' ')
             .AppendUnderlyingType(discriminatedUnion.UnderlyingType)
             .Append(' ')
-            .AppendType(discriminatedUnion.Type, false)
+            .AppendType(discriminatedUnion.Type, false, false, true)
             .AppendLine()
             .TryAppendConstraints(discriminatedUnion.Type.TypeMetadata.TypeParameters, SpaceIndentedBy8)
             .AppendPragmaWarning(true, Sa1601)
diff --git a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/OutputStage/StringBuilderExtensions.cs b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/OutputStage/StringBuilderExtensions.cs
index 6469756..880de03 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator.Baseline/OutputStage/StringBuilderExtensions.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator.Baseline/OutputStage/StringBuilderExtensions.cs
@@ -12,6 +12,7 @@ namespace Sundew.DiscriminatedUnions.Generator.OutputStage;
 using System.Linq;
 using System.Reflection;
 using System.Text;
+using Microsoft.CodeAnalysis;
 using Sundew.Base.Collections.Immutable;
 using Sundew.Base.Text;
 using Sundew.DiscriminatedUnions.Generator.DeclarationStage;
@@ -39,8 +40,10 @@ internal static class StringBuilderExtensions
     private const string SummaryStart = "/// <summary>";
     private const string SummaryEnd = "/// </summary>";
     private const string Documentation = "/// ";
+    private const string OutText = "out";
+    private const string InText = "in";
 
-    public static StringBuilder AppendType(this StringBuilder stringBuilder, in FullType fullType, bool fullyQualify = true, bool omitTypeParameters = false)
+    public static StringBuilder AppendType(this StringBuilder stringBuilder, in FullType fullType, bool fullyQualify = true, bool isForAttribute = false, bool isForPartial = false)
     {
         if (fullyQualify && fullType.Namespace != string.Empty)
         {
@@ -51,7 +54,18 @@ public static StringBuilder AppendType(this StringBuilder stringBuilder, in Full
                 .Append('.');
         }
 
-        stringBuilder.Append(omitTypeParameters ? fullType.NameForTypeOfAttribute : fullType.TypeMetadata.FullName);
+        if (isForAttribute)
+        {
+            stringBuilder.Append(fullType.NameForTypeOfAttribute);
+        }
+        else if (isForPartial)
+        {
+            stringBuilder.Append(fullType.Name).TryAppendGenericQualifier(fullType, false, false);
+        }
+        else
+        {
+            stringBuilder.Append(fullType.TypeMetadata.FullName);
+        }
 
         if (fullType.IsArray)
         {
@@ -61,22 +75,40 @@ public static StringBuilder AppendType(this StringBuilder stringBuilder, in Full
         return stringBuilder;
     }
 
-    public static StringBuilder TryAppendGenericQualifier(this StringBuilder stringBuilder, in FullType fullType, bool omitTypeParameters = false)
+    public static StringBuilder TryAppendGenericQualifier(this StringBuilder stringBuilder, in FullType fullType, bool omitTypeParameters = false, bool omitVariance = true)
     {
-        if (fullType.TypeMetadata.GenericQualifier != null)
+        string GetVariance(TypeParameter typeParameter)
         {
-            if (!omitTypeParameters)
+            return typeParameter.VarianceKind switch
             {
-                stringBuilder.Append(fullType.TypeMetadata.GenericQualifier);
-            }
-            else
+                VarianceKind.None => throw new ArgumentOutOfRangeException(),
+                VarianceKind.Out => OutText,
+                VarianceKind.In => InText,
+                _ => throw new UnreachableCaseException(typeParameter.VarianceKind.GetType()),
+            };
+        }
+
+        var typeParameterCount = fullType.TypeMetadata.TypeParameters.Count;
+        if (typeParameterCount > 0)
+        {
+            if (!omitTypeParameters)
             {
-                var typeParameterCount = fullType.TypeMetadata.TypeParameters.Count;
+                const string separator = ", ";
                 stringBuilder
                     .Append('<')
-                    .If(typeParameterCount > 0, stringBuilder => stringBuilder.Append(',', typeParameterCount - 1))
+                    .AppendItems(
+                        fullType.TypeMetadata.TypeParameters,
+                        (builder, typeParameter) =>
+                        {
+                            builder.If(!omitVariance && typeParameter.VarianceKind != VarianceKind.None, builder => builder.Append(GetVariance(typeParameter)).Append(' ')).Append(typeParameter.Name);
+                        },
+                        separator)
                     .Append('>');
             }
+            else
+            {
+                stringBuilder.Append('<').Append(',', typeParameterCount - 1).Append('>');
+            }
         }
 
         return stringBuilder;
diff --git a/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameterExtensions{T}.generated.verified.cs b/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameterExtensions{T}.generated.verified.cs
new file mode 100644
index 0000000..5667bf7
--- /dev/null
+++ b/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameterExtensions{T}.generated.verified.cs
@@ -0,0 +1,36 @@
+//HintName: Sundew.DiscriminatedUnions.Tester.IGenericOutParameterExtensions{T}.generated.cs
+#nullable enable
+
+namespace Sundew.DiscriminatedUnions.Tester
+{
+    /// <summary>
+    /// Segregation extension method for IGenericOutParameter.
+    /// </summary>
+    [global::System.Diagnostics.DebuggerNonUserCode]
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Sundew.DiscriminateUnions.Generator", "5.3.0.0")]
+    public static partial class IGenericOutParameterExtensions
+    {
+        /// <summary>
+        /// Segregates the items in the specified enumerable by type.
+        /// </summary>
+        /// <param name="iGenericOutParameters">The iGenericOutParameters.</param>
+        /// <returns>A new IGenericOutParameterSegregation.</returns>
+        public static IGenericOutParameterSegregation<T> Segregate<T>(this System.Collections.Generic.IEnumerable<global::Sundew.DiscriminatedUnions.Tester.IGenericOutParameter<T>> iGenericOutParameters)
+            where T : notnull
+        {
+            var genericOutParameters = new System.Collections.Generic.List<global::Sundew.DiscriminatedUnions.Tester.GenericOutParameter<T>>();
+
+            foreach (var value in iGenericOutParameters)
+            {
+                switch (value)
+                {
+                    case global::Sundew.DiscriminatedUnions.Tester.GenericOutParameter<T> genericOutParameter:
+                        genericOutParameters.Add(genericOutParameter);
+                        break;
+                }
+            }
+
+            return new global::Sundew.DiscriminatedUnions.Tester.IGenericOutParameterSegregation<T>(genericOutParameters);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameterSegregation{T}.generated.verified.cs b/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameterSegregation{T}.generated.verified.cs
new file mode 100644
index 0000000..8eba4a4
--- /dev/null
+++ b/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameterSegregation{T}.generated.verified.cs
@@ -0,0 +1,25 @@
+//HintName: Sundew.DiscriminatedUnions.Tester.IGenericOutParameterSegregation{T}.generated.cs
+#nullable enable
+
+namespace Sundew.DiscriminatedUnions.Tester
+{
+    /// <summary>
+    /// Contains individual lists of the different cases of the discriminated union IGenericOutParameter.
+    /// </summary>
+    [global::System.Diagnostics.DebuggerNonUserCode]
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Sundew.DiscriminateUnions.Generator", "5.3.0.0")]
+    public sealed partial class IGenericOutParameterSegregation<T>
+        where T : notnull
+    {
+        internal IGenericOutParameterSegregation(System.Collections.Generic.IReadOnlyList<global::Sundew.DiscriminatedUnions.Tester.GenericOutParameter<T>> genericOutParameters)
+        {
+            this.GenericOutParameters = genericOutParameters;
+        }
+
+        /// <summary>
+        /// Gets the GenericOutParameters.
+        /// </summary>
+        /// <returns>The GenericOutParameters.</returns>
+        public System.Collections.Generic.IReadOnlyList<global::Sundew.DiscriminatedUnions.Tester.GenericOutParameter<T>> GenericOutParameters { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameter{T}.generated.verified.cs b/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameter{T}.generated.verified.cs
new file mode 100644
index 0000000..6cde068
--- /dev/null
+++ b/Source/Sundew.DiscriminatedUnions.Generator.IntegrationTests/DiscriminatedUnionGeneratorFixture.VerifyGeneratedSources#Sundew.DiscriminatedUnions.Tester.IGenericOutParameter{T}.generated.verified.cs
@@ -0,0 +1,22 @@
+//HintName: Sundew.DiscriminatedUnions.Tester.IGenericOutParameter{T}.generated.cs
+#nullable enable
+
+namespace Sundew.DiscriminatedUnions.Tester
+{
+#pragma warning disable SA1601
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Sundew.DiscriminateUnions.Generator", "5.3.0.0")]
+    public partial interface IGenericOutParameter<out T>
+        where T : notnull
+#pragma warning restore SA1601
+    {
+        /// <summary>
+        /// Factory method for the GenericOutParameter case.
+        /// </summary>
+        /// <param name="value">The value.</param>
+        /// <returns>A new GenericOutParameter.</returns>
+        [Sundew.DiscriminatedUnions.CaseType(typeof(global::Sundew.DiscriminatedUnions.Tester.GenericOutParameter<>))]
+        [global::System.Diagnostics.DebuggerNonUserCode]
+        public static global::Sundew.DiscriminatedUnions.Tester.IGenericOutParameter<T> GenericOutParameter(T value)
+            => new global::Sundew.DiscriminatedUnions.Tester.GenericOutParameter<T>(value);
+    }
+}
diff --git a/Source/Sundew.DiscriminatedUnions.Generator/CodeAnalysisHelper.cs b/Source/Sundew.DiscriminatedUnions.Generator/CodeAnalysisHelper.cs
index 05194e4..19bb369 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator/CodeAnalysisHelper.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator/CodeAnalysisHelper.cs
@@ -16,9 +16,13 @@ namespace Sundew.DiscriminatedUnions.Generator;
 using Sundew.DiscriminatedUnions.Generator.Model;
 using Sundew.DiscriminatedUnions.Shared;
 using static Sundew.DiscriminatedUnions.Generator.OutputStage.GeneratorConstants;
+using Type = Sundew.DiscriminatedUnions.Generator.Model.Type;
 
 internal static class CodeAnalysisHelper
 {
+    private const string? OutText = "out";
+    private const string? InText = "in";
+
     private static readonly HashSet<string> Keywords = new HashSet<string>
     {
         "abstract",
@@ -172,18 +176,6 @@ public static Type GetSourceType(this ITypeSymbol typeSymbol)
 
     public static FullType GetFullType(this ITypeSymbol typeSymbol, bool useFullyQualifiedFormat = false)
     {
-        string? GetGenericQualifier(INamedTypeSymbol namedTypeSymbol)
-        {
-            var name = namedTypeSymbol.ToDisplayString(useFullyQualifiedFormat ? FullyQualifiedDisplayFormat : NameQualifiedTypeFormat);
-            var index = name.IndexOf('<');
-            if (index > -1)
-            {
-                return name.Substring(index);
-            }
-
-            return null;
-        }
-
         switch (typeSymbol)
         {
             case INamedTypeSymbol namedTypeSymbol:
@@ -195,12 +187,10 @@ public static FullType GetFullType(this ITypeSymbol typeSymbol, bool useFullyQua
                     isShortNameAlias ? string.Empty : GlobalAssemblyAlias,
                     false,
                     new TypeMetadata(
-                        !isShortNameAlias && namedTypeSymbol.IsTypeGenericWithTypeParameters()
-                            ? GetGenericQualifier(namedTypeSymbol)
-                            : null,
                         fullName,
                         namedTypeSymbol.TypeParameters.Select(x => new TypeParameter(
                             x.Name,
+                            x.Variance,
                             GetUnderlyingTypeConstraint(x)
                                 .Concat(x.ConstraintTypes.Select(x =>
                                     x.ToDisplayString(FullyQualifiedDisplayFormat)))
@@ -213,9 +203,9 @@ public static FullType GetFullType(this ITypeSymbol typeSymbol, bool useFullyQua
                     elementAttributeName,
                     elementIsShortNameAlias ? string.Empty : GlobalAssemblyAlias,
                     true,
-                    new TypeMetadata(null, elementFullName, ImmutableArray<TypeParameter>.Empty));
+                    new TypeMetadata(elementFullName, ImmutableArray<TypeParameter>.Empty));
             case ITypeParameterSymbol typeParameterSymbol:
-                return new FullType(typeParameterSymbol.MetadataName, string.Empty, string.Empty, string.Empty, false, new TypeMetadata(null, string.Empty, ImmutableArray<TypeParameter>.Empty));
+                return new FullType(typeParameterSymbol.MetadataName, string.Empty, string.Empty, string.Empty, false, new TypeMetadata(string.Empty, ImmutableArray<TypeParameter>.Empty));
             default:
                 throw new System.ArgumentOutOfRangeException(nameof(typeSymbol));
         }
diff --git a/Source/Sundew.DiscriminatedUnions.Generator/DeclarationStage/TypeParameter.cs b/Source/Sundew.DiscriminatedUnions.Generator/DeclarationStage/TypeParameter.cs
index 5e4f036..ab966cd 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator/DeclarationStage/TypeParameter.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator/DeclarationStage/TypeParameter.cs
@@ -7,6 +7,7 @@
 
 namespace Sundew.DiscriminatedUnions.Generator.DeclarationStage;
 
+using Microsoft.CodeAnalysis;
 using Sundew.Base.Collections.Immutable;
 
-internal readonly record struct TypeParameter(string Name, ValueArray<string> Constraints);
\ No newline at end of file
+internal readonly record struct TypeParameter(string Name, VarianceKind VarianceKind, ValueArray<string> Constraints);
\ No newline at end of file
diff --git a/Source/Sundew.DiscriminatedUnions.Generator/Model/TypeMetadata.cs b/Source/Sundew.DiscriminatedUnions.Generator/Model/TypeMetadata.cs
index 6d8394a..c1bc78f 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator/Model/TypeMetadata.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator/Model/TypeMetadata.cs
@@ -10,4 +10,4 @@ namespace Sundew.DiscriminatedUnions.Generator.Model;
 using Sundew.Base.Collections.Immutable;
 using Sundew.DiscriminatedUnions.Generator.DeclarationStage;
 
-internal readonly record struct TypeMetadata(string? GenericQualifier, string FullName, ValueArray<TypeParameter> TypeParameters);
\ No newline at end of file
+internal readonly record struct TypeMetadata(string FullName, ValueArray<TypeParameter> TypeParameters);
\ No newline at end of file
diff --git a/Source/Sundew.DiscriminatedUnions.Generator/OutputStage/DiscriminatedUnionOutputProvider.cs b/Source/Sundew.DiscriminatedUnions.Generator/OutputStage/DiscriminatedUnionOutputProvider.cs
index 634a29c..828c73f 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator/OutputStage/DiscriminatedUnionOutputProvider.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator/OutputStage/DiscriminatedUnionOutputProvider.cs
@@ -112,7 +112,7 @@ private static string GetUnionSource(in DiscriminatedUnion discriminatedUnion, s
             .Append(' ')
             .AppendUnderlyingType(discriminatedUnion.UnderlyingType)
             .Append(' ')
-            .AppendType(discriminatedUnion.Type, false)
+            .AppendType(discriminatedUnion.Type, false, false, true)
             .AppendLine()
             .TryAppendConstraints(discriminatedUnion.Type.TypeMetadata.TypeParameters, SpaceIndentedBy8)
             .AppendPragmaWarning(true, Sa1601)
diff --git a/Source/Sundew.DiscriminatedUnions.Generator/OutputStage/StringBuilderExtensions.cs b/Source/Sundew.DiscriminatedUnions.Generator/OutputStage/StringBuilderExtensions.cs
index 6469756..880de03 100644
--- a/Source/Sundew.DiscriminatedUnions.Generator/OutputStage/StringBuilderExtensions.cs
+++ b/Source/Sundew.DiscriminatedUnions.Generator/OutputStage/StringBuilderExtensions.cs
@@ -12,6 +12,7 @@ namespace Sundew.DiscriminatedUnions.Generator.OutputStage;
 using System.Linq;
 using System.Reflection;
 using System.Text;
+using Microsoft.CodeAnalysis;
 using Sundew.Base.Collections.Immutable;
 using Sundew.Base.Text;
 using Sundew.DiscriminatedUnions.Generator.DeclarationStage;
@@ -39,8 +40,10 @@ internal static class StringBuilderExtensions
     private const string SummaryStart = "/// <summary>";
     private const string SummaryEnd = "/// </summary>";
     private const string Documentation = "/// ";
+    private const string OutText = "out";
+    private const string InText = "in";
 
-    public static StringBuilder AppendType(this StringBuilder stringBuilder, in FullType fullType, bool fullyQualify = true, bool omitTypeParameters = false)
+    public static StringBuilder AppendType(this StringBuilder stringBuilder, in FullType fullType, bool fullyQualify = true, bool isForAttribute = false, bool isForPartial = false)
     {
         if (fullyQualify && fullType.Namespace != string.Empty)
         {
@@ -51,7 +54,18 @@ public static StringBuilder AppendType(this StringBuilder stringBuilder, in Full
                 .Append('.');
         }
 
-        stringBuilder.Append(omitTypeParameters ? fullType.NameForTypeOfAttribute : fullType.TypeMetadata.FullName);
+        if (isForAttribute)
+        {
+            stringBuilder.Append(fullType.NameForTypeOfAttribute);
+        }
+        else if (isForPartial)
+        {
+            stringBuilder.Append(fullType.Name).TryAppendGenericQualifier(fullType, false, false);
+        }
+        else
+        {
+            stringBuilder.Append(fullType.TypeMetadata.FullName);
+        }
 
         if (fullType.IsArray)
         {
@@ -61,22 +75,40 @@ public static StringBuilder AppendType(this StringBuilder stringBuilder, in Full
         return stringBuilder;
     }
 
-    public static StringBuilder TryAppendGenericQualifier(this StringBuilder stringBuilder, in FullType fullType, bool omitTypeParameters = false)
+    public static StringBuilder TryAppendGenericQualifier(this StringBuilder stringBuilder, in FullType fullType, bool omitTypeParameters = false, bool omitVariance = true)
     {
-        if (fullType.TypeMetadata.GenericQualifier != null)
+        string GetVariance(TypeParameter typeParameter)
         {
-            if (!omitTypeParameters)
+            return typeParameter.VarianceKind switch
             {
-                stringBuilder.Append(fullType.TypeMetadata.GenericQualifier);
-            }
-            else
+                VarianceKind.None => throw new ArgumentOutOfRangeException(),
+                VarianceKind.Out => OutText,
+                VarianceKind.In => InText,
+                _ => throw new UnreachableCaseException(typeParameter.VarianceKind.GetType()),
+            };
+        }
+
+        var typeParameterCount = fullType.TypeMetadata.TypeParameters.Count;
+        if (typeParameterCount > 0)
+        {
+            if (!omitTypeParameters)
             {
-                var typeParameterCount = fullType.TypeMetadata.TypeParameters.Count;
+                const string separator = ", ";
                 stringBuilder
                     .Append('<')
-                    .If(typeParameterCount > 0, stringBuilder => stringBuilder.Append(',', typeParameterCount - 1))
+                    .AppendItems(
+                        fullType.TypeMetadata.TypeParameters,
+                        (builder, typeParameter) =>
+                        {
+                            builder.If(!omitVariance && typeParameter.VarianceKind != VarianceKind.None, builder => builder.Append(GetVariance(typeParameter)).Append(' ')).Append(typeParameter.Name);
+                        },
+                        separator)
                     .Append('>');
             }
+            else
+            {
+                stringBuilder.Append('<').Append(',', typeParameterCount - 1).Append('>');
+            }
         }
 
         return stringBuilder;
diff --git a/Source/Sundew.DiscriminatedUnions.TestData/Sundew.DiscriminatedUnions.TestData.csproj b/Source/Sundew.DiscriminatedUnions.TestData/Sundew.DiscriminatedUnions.TestData.csproj
index 7aa57e1..2f352f6 100644
--- a/Source/Sundew.DiscriminatedUnions.TestData/Sundew.DiscriminatedUnions.TestData.csproj
+++ b/Source/Sundew.DiscriminatedUnions.TestData/Sundew.DiscriminatedUnions.TestData.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
diff --git a/Source/Sundew.DiscriminatedUnions.Tester/IGenericOutParameter.cs b/Source/Sundew.DiscriminatedUnions.Tester/IGenericOutParameter.cs
new file mode 100644
index 0000000..7811df2
--- /dev/null
+++ b/Source/Sundew.DiscriminatedUnions.Tester/IGenericOutParameter.cs
@@ -0,0 +1,12 @@
+namespace Sundew.DiscriminatedUnions.Tester;
+
+[DiscriminatedUnion(generatorFeatures: GeneratorFeatures.Segregate)]
+public partial interface IGenericOutParameter<out T>
+    where T : notnull
+{
+
+}
+
+
+public sealed record GenericOutParameter<T>(T Value) : IGenericOutParameter<T>
+    where T : notnull;
\ No newline at end of file
diff --git a/Source/Sundew.DiscriminatedUnions.Tester/Sundew.DiscriminatedUnions.Tester.csproj b/Source/Sundew.DiscriminatedUnions.Tester/Sundew.DiscriminatedUnions.Tester.csproj
index 14b7dcb..7129fde 100644
--- a/Source/Sundew.DiscriminatedUnions.Tester/Sundew.DiscriminatedUnions.Tester.csproj
+++ b/Source/Sundew.DiscriminatedUnions.Tester/Sundew.DiscriminatedUnions.Tester.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <IsPackable>false</IsPackable>
   </PropertyGroup>