diff --git a/src/HotChocolate/Core/src/Types/Configuration/ExtendedTypeReferenceEqualityComparer.cs b/src/HotChocolate/Core/src/Types/Configuration/ExtendedTypeRefEqualityComparer.cs
similarity index 75%
rename from src/HotChocolate/Core/src/Types/Configuration/ExtendedTypeReferenceEqualityComparer.cs
rename to src/HotChocolate/Core/src/Types/Configuration/ExtendedTypeRefEqualityComparer.cs
index 840f5c2ccf3..ce3c6758b60 100644
--- a/src/HotChocolate/Core/src/Types/Configuration/ExtendedTypeReferenceEqualityComparer.cs
+++ b/src/HotChocolate/Core/src/Types/Configuration/ExtendedTypeRefEqualityComparer.cs
@@ -9,10 +9,9 @@
 
 namespace HotChocolate.Configuration;
 
-internal sealed class ExtendedTypeReferenceEqualityComparer
-    : IEqualityComparer<ExtendedTypeReference>
+internal sealed class ExtendedTypeRefEqualityComparer : IEqualityComparer<ExtendedTypeReference>
 {
-    public bool Equals([AllowNull] ExtendedTypeReference x, [AllowNull] ExtendedTypeReference y)
+    public bool Equals(ExtendedTypeReference? x, ExtendedTypeReference? y)
     {
         if (ReferenceEquals(x, y))
         {
@@ -39,7 +38,7 @@ public bool Equals([AllowNull] ExtendedTypeReference x, [AllowNull] ExtendedType
         return Equals(x.Type, y.Type);
     }
 
-    private static bool Equals([AllowNull] IExtendedType x, [AllowNull] IExtendedType y)
+    private static bool Equals(IExtendedType? x, IExtendedType? y)
     {
         if (ReferenceEquals(x, y))
         {
@@ -54,7 +53,7 @@ private static bool Equals([AllowNull] IExtendedType x, [AllowNull] IExtendedTyp
         return ReferenceEquals(x.Type, y.Type) && x.Kind == y.Kind;
     }
 
-    public int GetHashCode([DisallowNull] ExtendedTypeReference obj)
+    public int GetHashCode(ExtendedTypeReference obj)
     {
         unchecked
         {
@@ -69,7 +68,7 @@ public int GetHashCode([DisallowNull] ExtendedTypeReference obj)
         }
     }
 
-    private static int GetHashCode([DisallowNull] IExtendedType obj)
+    private static int GetHashCode(IExtendedType obj)
     {
         unchecked
         {
@@ -78,11 +77,10 @@ private static int GetHashCode([DisallowNull] IExtendedType obj)
 
             for (var i = 0; i < obj.TypeArguments.Count; i++)
             {
-                hashCode ^= (GetHashCode(obj.TypeArguments[i]) * 397 * i);
+                hashCode ^= GetHashCode(obj.TypeArguments[i]) * 397 * i;
             }
 
             return hashCode;
         }
     }
-
 }
diff --git a/src/HotChocolate/Core/src/Types/Configuration/Handlers/ExtendedTypeReferenceHandler.cs b/src/HotChocolate/Core/src/Types/Configuration/Handlers/ExtendedTypeReferenceHandler.cs
index e1cba59b55d..e7093ef3e95 100644
--- a/src/HotChocolate/Core/src/Types/Configuration/Handlers/ExtendedTypeReferenceHandler.cs
+++ b/src/HotChocolate/Core/src/Types/Configuration/Handlers/ExtendedTypeReferenceHandler.cs
@@ -69,10 +69,7 @@ private static void TryMapToExistingRegistration(
 
         foreach (var component in typeInfo.Components)
         {
-            normalizedTypeRef = TypeReference.Create(
-                component.Type,
-                context,
-                scope);
+            normalizedTypeRef = TypeReference.Create(component.Type, context, scope);
 
             if (typeRegistrar.IsResolved(normalizedTypeRef))
             {
diff --git a/src/HotChocolate/Core/src/Types/Configuration/TypeDiscoverer.cs b/src/HotChocolate/Core/src/Types/Configuration/TypeDiscoverer.cs
index 9317345ee2c..336f43c31e1 100644
--- a/src/HotChocolate/Core/src/Types/Configuration/TypeDiscoverer.cs
+++ b/src/HotChocolate/Core/src/Types/Configuration/TypeDiscoverer.cs
@@ -174,6 +174,9 @@ private bool TryInferTypes()
 
                     if (unresolvedTypeRef is ExtendedTypeReference typeRef)
                     {
+                        // we normalize the type context so that we can correctly lookup
+                        // if a type is already registered.
+                        typeRef = typeRef.WithContext(schemaTypeRef.Context);
                         _typeRegistry.TryRegister(typeRef, schemaTypeRef);
                     }
                 }
diff --git a/src/HotChocolate/Core/src/Types/Configuration/TypeRegistry.cs b/src/HotChocolate/Core/src/Types/Configuration/TypeRegistry.cs
index 92f4b5879b5..cd9d601d29b 100644
--- a/src/HotChocolate/Core/src/Types/Configuration/TypeRegistry.cs
+++ b/src/HotChocolate/Core/src/Types/Configuration/TypeRegistry.cs
@@ -15,7 +15,7 @@ internal sealed class TypeRegistry
 {
     private readonly Dictionary<TypeReference, RegisteredType> _typeRegister = new();
     private readonly Dictionary<ExtendedTypeReference, TypeReference> _runtimeTypeRefs =
-        new(new ExtendedTypeReferenceEqualityComparer());
+        new(new ExtendedTypeRefEqualityComparer());
     private readonly Dictionary<string, TypeReference> _nameRefs = new(StringComparer.Ordinal);
     private readonly List<RegisteredType> _types = new();
     private readonly TypeInterceptor _typeRegistryInterceptor;
@@ -47,9 +47,9 @@ public bool IsRegistered(TypeReference typeReference)
             return true;
         }
 
-        if (typeReference is ExtendedTypeReference clrTypeReference)
+        if (typeReference is ExtendedTypeReference extendedTypeRef)
         {
-            return _runtimeTypeRefs.ContainsKey(clrTypeReference);
+            return _runtimeTypeRefs.ContainsKey(extendedTypeRef);
         }
 
         return false;
diff --git a/src/HotChocolate/Core/src/Types/Properties/TypeResources.Designer.cs b/src/HotChocolate/Core/src/Types/Properties/TypeResources.Designer.cs
index 463e33348f7..5fb57f57bb1 100644
--- a/src/HotChocolate/Core/src/Types/Properties/TypeResources.Designer.cs
+++ b/src/HotChocolate/Core/src/Types/Properties/TypeResources.Designer.cs
@@ -1946,5 +1946,17 @@ internal static string ErrorHelper_FetchedToManyNodesAtOnce {
                 return ResourceManager.GetString("ErrorHelper_FetchedToManyNodesAtOnce", resourceCulture);
             }
         }
+        
+        internal static string ThrowHelper_InputTypeExpected_Message {
+            get {
+                return ResourceManager.GetString("ThrowHelper_InputTypeExpected_Message", resourceCulture);
+            }
+        }
+        
+        internal static string ThrowHelper_OutputTypeExpected_Message {
+            get {
+                return ResourceManager.GetString("ThrowHelper_OutputTypeExpected_Message", resourceCulture);
+            }
+        }
     }
 }
diff --git a/src/HotChocolate/Core/src/Types/Properties/TypeResources.resx b/src/HotChocolate/Core/src/Types/Properties/TypeResources.resx
index 64177e3f8b8..26ea0160950 100644
--- a/src/HotChocolate/Core/src/Types/Properties/TypeResources.resx
+++ b/src/HotChocolate/Core/src/Types/Properties/TypeResources.resx
@@ -1083,4 +1083,10 @@ Type: `{0}`</value>
   <data name="ErrorHelper_FetchedToManyNodesAtOnce" xml:space="preserve">
     <value>The maximum number of nodes that can be fetched at once is {0}. This selection tried to fetch {1} nodes that exceeded the maximum allowed amount.</value>
   </data>
+  <data name="ThrowHelper_InputTypeExpected_Message" xml:space="preserve">
+    <value>The specified type `{0}` is expected to be an input type.</value>
+  </data>
+  <data name="ThrowHelper_OutputTypeExpected_Message" xml:space="preserve">
+    <value>The specified type `{0}` is expected to be an output type.</value>
+  </data>
 </root>
diff --git a/src/HotChocolate/Core/src/Types/Types/Argument.cs b/src/HotChocolate/Core/src/Types/Types/Argument.cs
index ac22acbbb1e..f3aba673826 100644
--- a/src/HotChocolate/Core/src/Types/Types/Argument.cs
+++ b/src/HotChocolate/Core/src/Types/Types/Argument.cs
@@ -101,7 +101,7 @@ protected override void OnCompleteField(
 
         base.OnCompleteField(context, declaringMember, definition);
 
-        Type = context.GetType<IInputType>(definition.Type!);
+        Type = context.GetType<IInputType>(definition.Type!).EnsureInputType();
         _runtimeType = definition.RuntimeType ?? definition.Parameter?.ParameterType!;
         _runtimeType = CompleteRuntimeType(Type, _runtimeType, out var isOptional);
         DefaultValue = CompleteDefaultValue(context, definition, Type, Coordinate);
diff --git a/src/HotChocolate/Core/src/Types/Types/Descriptors/TypeReferences/ExtendedTypeReference.cs b/src/HotChocolate/Core/src/Types/Types/Descriptors/TypeReferences/ExtendedTypeReference.cs
index 00d6bf94ce1..c76134e7dc8 100644
--- a/src/HotChocolate/Core/src/Types/Types/Descriptors/TypeReferences/ExtendedTypeReference.cs
+++ b/src/HotChocolate/Core/src/Types/Types/Descriptors/TypeReferences/ExtendedTypeReference.cs
@@ -12,6 +12,21 @@ public sealed class ExtendedTypeReference
     : TypeReference
     , IEquatable<ExtendedTypeReference>
 {
+    /// <summary>
+    /// Initializes a new instance of <see cref="ExtendedTypeReference"/>.
+    /// </summary>
+    /// <param name="type">
+    /// The extended type.
+    /// </param>
+    /// <param name="context">
+    /// The type context.
+    /// </param>
+    /// <param name="scope">
+    /// The type scope.
+    /// </param>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     internal ExtendedTypeReference(
         IExtendedType type,
         TypeContext context,
@@ -91,17 +106,25 @@ public override bool Equals(object? obj)
 
     /// <inheritdoc />
     public override int GetHashCode()
-    {
-        unchecked
-        {
-            return base.GetHashCode() ^ Type.GetHashCode() * 397;
-        }
-    }
+        => HashCode.Combine(base.GetHashCode(), Type.GetHashCode());
 
     /// <inheritdoc />
     public override string ToString()
         => ToString(Type);
 
+    /// <summary>
+    /// Creates a new <see cref="ExtendedTypeReference"/> and
+    /// replaces the <see cref="Type"/> with the provided <paramref name="type"/>.
+    /// </summary>
+    /// <param name="type">
+    /// The extended type.
+    /// </param>
+    /// <returns>
+    /// Returns a new <see cref="ExtendedTypeReference"/>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public ExtendedTypeReference WithType(IExtendedType type)
     {
         if (type is null)
@@ -109,36 +132,87 @@ public ExtendedTypeReference WithType(IExtendedType type)
             throw new ArgumentNullException(nameof(type));
         }
 
-        return Create(
-            type,
-            Context,
-            Scope);
+        if (type.Equals(Type))
+        {
+            return this;
+        }
+
+        return Create(type, Context, Scope);
     }
 
+    /// <summary>
+    /// Creates a new <see cref="ExtendedTypeReference"/> and replaces the
+    /// <see cref="TypeReference.Context"/> with the provided <paramref name="context"/>.
+    /// </summary>
+    /// <param name="context">
+    /// The type context.
+    /// </param>
+    /// <returns>
+    /// Returns a new <see cref="ExtendedTypeReference"/>.
+    /// </returns>
     public ExtendedTypeReference WithContext(TypeContext context = TypeContext.None)
     {
+        if (context == Context)
+        {
+            return this;
+        }
+
         return Create(
             Type,
             context,
             Scope);
     }
 
+    /// <summary>
+    /// Creates a new <see cref="ExtendedTypeReference"/> and replaces the
+    /// <see cref="TypeReference.Scope"/> with the provided
+    /// <paramref name="scope"/>.
+    /// </summary>
+    /// <param name="scope">
+    /// The type scope.
+    /// </param>
+    /// <returns>
+    /// Returns a new <see cref="ExtendedTypeReference"/>.
+    /// </returns>
     public ExtendedTypeReference WithScope(string? scope = null)
     {
+        if (string.Equals(scope, Scope, StringComparison.Ordinal))
+        {
+            return this;
+        }
+
         return Create(
             Type,
             Context,
             scope);
     }
 
+    /// <summary>
+    /// Creates a new <see cref="ExtendedTypeReference"/> and allows to replace certain aspects
+    /// of the original instance.
+    /// </summary>
+    /// <param name="type">
+    /// The extended type.
+    /// </param>
+    /// <param name="context">
+    /// The type context.
+    /// </param>
+    /// <param name="scope">
+    /// The type scope.
+    /// </param>
+    /// <returns>
+    /// Returns a new <see cref="ExtendedTypeReference"/>.
+    /// </returns>
     public ExtendedTypeReference With(
         IExtendedType? type = default,
         Optional<TypeContext> context = default,
         Optional<string?> scope = default)
-    {
-        return Create(
+        => Create(
             type ?? Type,
-            context.HasValue ? context.Value : Context,
-            scope.HasValue ? scope.Value : Scope);
-    }
+            context.HasValue
+                ? context.Value
+                : Context,
+            scope.HasValue
+                ? scope.Value
+                : Scope);
 }
diff --git a/src/HotChocolate/Core/src/Types/Types/Descriptors/TypeReferences/TypeReference.cs b/src/HotChocolate/Core/src/Types/Types/Descriptors/TypeReferences/TypeReference.cs
index 28bd7a42465..d8ab5c5edd9 100644
--- a/src/HotChocolate/Core/src/Types/Types/Descriptors/TypeReferences/TypeReference.cs
+++ b/src/HotChocolate/Core/src/Types/Types/Descriptors/TypeReferences/TypeReference.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using HotChocolate.Internal;
 using HotChocolate.Language;
 using HotChocolate.Utilities;
@@ -24,15 +25,32 @@ protected TypeReference(
         Scope = scope;
     }
 
-    /// <inheritdoc />
+    /// <summary>
+    /// Gets the kind of the type reference.
+    /// </summary>
     public TypeReferenceKind Kind { get; }
 
-    /// <inheritdoc />
+    /// <summary>
+    /// Specifies in which context the type reference is used
+    /// (input types, output types, neutral context).
+    /// </summary>
     public TypeContext Context { get; }
 
-    /// <inheritdoc />
+    /// <summary>
+    /// Gets the scope of the type reference.
+    /// The scope allows us to branch the type system.
+    /// </summary>
     public string? Scope { get; }
 
+    /// <summary>
+    /// A helper method to compare a type reference.
+    /// </summary>
+    /// <param name="other">
+    /// The other type reference.
+    /// </param>
+    /// <returns>
+    /// <c>true</c> if the type references are equal; otherwise, <c>false</c>.
+    /// </returns>
     protected bool IsEqual(TypeReference other)
     {
         if (Context != other.Context
diff --git a/src/HotChocolate/Core/src/Types/Types/Extensions/TypeExtensions.cs b/src/HotChocolate/Core/src/Types/Types/Extensions/TypeExtensions.cs
index 48886225dce..1d76f8656b3 100644
--- a/src/HotChocolate/Core/src/Types/Types/Extensions/TypeExtensions.cs
+++ b/src/HotChocolate/Core/src/Types/Types/Extensions/TypeExtensions.cs
@@ -5,22 +5,57 @@
 using HotChocolate.Properties;
 using HotChocolate.Utilities;
 using static HotChocolate.Utilities.ThrowHelper;
+using ThrowHelper = HotChocolate.Utilities.ThrowHelper;
 
 #nullable enable
 
 namespace HotChocolate.Types;
 
+/// <summary>
+/// Provides utility methods to work with <see cref="IType"/>.
+/// </summary>
 public static class TypeExtensions
 {
+    /// <summary>
+    /// Calculates the depth of a type. The depth is defined as the
+    /// number of wrapper types + the named type itself..
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns the depth of the type.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static int Depth(this IType type)
     {
+        if (type is null)
+        {
+            throw new ArgumentNullException(nameof(type));
+        }
+
         if (type is INamedType)
         {
             return 1;
         }
+
         return Depth(type.InnerType()) + 1;
     }
 
+    /// <summary>
+    /// Defines if a type is nullable.
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns <c>true</c> if the type is nullable; otherwise, <c>false</c>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static bool IsNullableType(this IType type)
     {
         if (type is null)
@@ -31,6 +66,18 @@ public static bool IsNullableType(this IType type)
         return type.Kind != TypeKind.NonNull;
     }
 
+    /// <summary>
+    /// Defines if a type is non-nullable.
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns <c>true</c> if the type is non-nullable; otherwise, <c>false</c>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static bool IsNonNullType(this IType type)
     {
         if (type is null)
@@ -41,6 +88,18 @@ public static bool IsNonNullType(this IType type)
         return type.Kind == TypeKind.NonNull;
     }
 
+    /// <summary>
+    /// Defines if a type is a composite type (object, interface or union).
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns <c>true</c> if the type is a composite type; otherwise, <c>false</c>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static bool IsCompositeType(this IType type)
     {
         if (type is null)
@@ -48,11 +107,21 @@ public static bool IsCompositeType(this IType type)
             throw new ArgumentNullException(nameof(type));
         }
 
-        return IsType(type, TypeKind.Object) ||
-           IsType(type, TypeKind.Interface) ||
-           IsType(type, TypeKind.Union);
+        return IsType(type, TypeKind.Object, TypeKind.Interface, TypeKind.Union);
     }
 
+    /// <summary>
+    /// Defines if a type is a complex type (object or interface).
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns <c>true</c> if the type is a complex type; otherwise, <c>false</c>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static bool IsComplexType(this IType type)
     {
         if (type is null)
@@ -60,10 +129,21 @@ public static bool IsComplexType(this IType type)
             throw new ArgumentNullException(nameof(type));
         }
 
-        return IsType(type, TypeKind.Object) ||
-            IsType(type, TypeKind.Interface);
+        return IsType(type, TypeKind.Object, TypeKind.Interface);
     }
 
+    /// <summary>
+    /// Defines if a type is a leaf type (scalar or enum).
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns <c>true</c> if the type is a leaf type; otherwise, <c>false</c>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static bool IsLeafType(this IType type)
     {
         if (type is null)
@@ -71,10 +151,21 @@ public static bool IsLeafType(this IType type)
             throw new ArgumentNullException(nameof(type));
         }
 
-        return IsType(type, TypeKind.Scalar) ||
-            IsType(type, TypeKind.Enum);
+        return IsType(type, TypeKind.Scalar, TypeKind.Enum);
     }
 
+    /// <summary>
+    /// Defines if a type is an list type.
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns <c>true</c> if the type is an list type; otherwise, <c>false</c>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static bool IsListType(this IType type)
     {
         if (type is null)
@@ -85,6 +176,18 @@ public static bool IsListType(this IType type)
         return IsType(type, TypeKind.List);
     }
 
+    /// <summary>
+    /// Defines if a type is a scalar type.
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns <c>true</c> if the type is a scalar type; otherwise, <c>false</c>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static bool IsScalarType(this IType type)
     {
         if (type is null)
@@ -95,6 +198,18 @@ public static bool IsScalarType(this IType type)
         return IsType(type, TypeKind.Scalar);
     }
 
+    /// <summary>
+    /// Defines if a type is an object type.
+    /// </summary>
+    /// <param name="type">
+    /// The type.
+    /// </param>
+    /// <returns>
+    /// Returns <c>true</c> if the type is an object type; otherwise, <c>false</c>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException">
+    /// <paramref name="type"/> is <c>null</c>.
+    /// </exception>
     public static bool IsObjectType(this IType type)
     {
         if (type is null)
@@ -145,6 +260,21 @@ public static bool IsInputType(this IType type)
         return type.NamedType() is IInputType;
     }
 
+    internal static IInputType EnsureInputType(this IType type)
+    {
+        if (type is null)
+        {
+            throw new ArgumentNullException(nameof(type));
+        }
+
+        if (type.NamedType() is not IInputType)
+        {
+            throw InputTypeExpected(type);
+        }
+
+        return (IInputType)type;
+    }
+
     public static bool IsOutputType(this IType type)
     {
         if (type is null)
@@ -155,6 +285,21 @@ public static bool IsOutputType(this IType type)
         return type.NamedType() is IOutputType;
     }
 
+    internal static IOutputType EnsureOutputType(this IType type)
+    {
+        if (type is null)
+        {
+            throw new ArgumentNullException(nameof(type));
+        }
+
+        if (type.NamedType() is not IOutputType)
+        {
+            throw OutputTypeExpected(type);
+        }
+
+        return (IOutputType)type;
+    }
+
     public static bool IsUnionType(this IType type)
     {
         if (type is null)
@@ -192,6 +337,7 @@ public static bool IsNamedType(this IType type)
         }
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
     internal static bool IsType(this IType type, TypeKind kind)
     {
         if (type.Kind == kind)
@@ -207,6 +353,46 @@ internal static bool IsType(this IType type, TypeKind kind)
         return false;
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static bool IsType(this IType type, TypeKind kind1, TypeKind kind2)
+    {
+        if (type.Kind == kind1 || type.Kind == kind2)
+        {
+            return true;
+        }
+
+        if (type.Kind == TypeKind.NonNull)
+        {
+            var innerKind = ((NonNullType)type).Type.Kind;
+            if (innerKind == kind1 || innerKind == kind2)
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static bool IsType(this IType type, TypeKind kind1, TypeKind kind2, TypeKind kind3)
+    {
+        if (type.Kind == kind1 || type.Kind == kind2 || type.Kind == kind3)
+        {
+            return true;
+        }
+
+        if (type.Kind == TypeKind.NonNull)
+        {
+            var innerKind = ((NonNullType)type).Type.Kind;
+            if (innerKind == kind1 || innerKind == kind2 || type.Kind == kind3)
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     public static IType InnerType(this IType type)
     {
         if (type is null)
@@ -234,7 +420,9 @@ public static IType NullableType(this IType type)
             throw new ArgumentNullException(nameof(type));
         }
 
-        return type.Kind != TypeKind.NonNull ? type : ((NonNullType)type).Type;
+        return type.Kind != TypeKind.NonNull
+            ? type
+            : ((NonNullType)type).Type;
     }
 
     public static string TypeName(this IType type)
@@ -262,6 +450,7 @@ public static ListType ListType(this IType type)
         if (type.Kind == TypeKind.NonNull)
         {
             var innerType = ((NonNullType)type).Type;
+
             if (innerType.Kind == TypeKind.List)
             {
                 return (ListType)innerType;
@@ -391,8 +580,7 @@ public static ITypeNode ToTypeNode(this IType type)
             throw new ArgumentNullException(nameof(type));
         }
 
-        if (type is NonNullType nnt
-            && ToTypeNode(nnt.Type) is INullableTypeNode nntn)
+        if (type is NonNullType nnt && ToTypeNode(nnt.Type) is INullableTypeNode nntn)
         {
             return new NonNullTypeNode(null, nntn);
         }
@@ -415,15 +603,16 @@ public static ITypeNode ToTypeNode(
         this IType original,
         INamedType namedType)
     {
-        if (original is NonNullType nnt
-            && ToTypeNode(nnt.Type, namedType) is INullableTypeNode nntn)
+        if (original is NonNullType nnt &&
+            ToTypeNode(nnt.Type, namedType) is INullableTypeNode nntn)
         {
             return new NonNullTypeNode(null, nntn);
         }
 
         if (original is ListType lt)
         {
-            return new ListTypeNode(null,
+            return new ListTypeNode(
+                null,
                 ToTypeNode(lt.ElementType, namedType));
         }
 
diff --git a/src/HotChocolate/Core/src/Types/Types/InputField.cs b/src/HotChocolate/Core/src/Types/Types/InputField.cs
index fed67b41153..2c7e602b4fe 100644
--- a/src/HotChocolate/Core/src/Types/Types/InputField.cs
+++ b/src/HotChocolate/Core/src/Types/Types/InputField.cs
@@ -78,7 +78,7 @@ protected override void OnCompleteField(
     {
         base.OnCompleteField(context, declaringMember, definition);
 
-        Type = context.GetType<IInputType>(definition.Type!);
+        Type = context.GetType<IInputType>(definition.Type!).EnsureInputType();
         _runtimeType = definition.RuntimeType ?? definition.Property?.PropertyType!;
         _runtimeType = CompleteRuntimeType(Type, _runtimeType, out var isOptional);
         DefaultValue = CompleteDefaultValue(context, definition, Type, Coordinate);
diff --git a/src/HotChocolate/Core/src/Types/Types/OutputFieldBase.cs b/src/HotChocolate/Core/src/Types/Types/OutputFieldBase.cs
index 4a4754946f5..25b58f93d64 100644
--- a/src/HotChocolate/Core/src/Types/Types/OutputFieldBase.cs
+++ b/src/HotChocolate/Core/src/Types/Types/OutputFieldBase.cs
@@ -56,7 +56,7 @@ protected override void OnCompleteField(
     {
         base.OnCompleteField(context, declaringMember, definition);
 
-        Type = context.GetType<IOutputType>(definition.Type!);
+        Type = context.GetType<IOutputType>(definition.Type!).EnsureOutputType();
         _runtimeType = CompleteRuntimeType(Type, null);
         Arguments = OnCompleteFields(context, definition);
     }
diff --git a/src/HotChocolate/Core/src/Types/Types/Scalars/JsonType.cs b/src/HotChocolate/Core/src/Types/Types/Scalars/JsonType.cs
index 868c4b5d34f..9e6473a98e3 100644
--- a/src/HotChocolate/Core/src/Types/Types/Scalars/JsonType.cs
+++ b/src/HotChocolate/Core/src/Types/Types/Scalars/JsonType.cs
@@ -182,7 +182,7 @@ public static JsonElement Format(IValueNode node)
             _visitor.Visit(node, new JsonFormatterContext(jsonWriter));
             jsonWriter.Flush();
 
-            var jsonReader = new Utf8JsonReader(bufferWriter.Body.Span);
+            var jsonReader = new Utf8JsonReader(bufferWriter.GetWrittenSpan());
             return JsonElement.ParseValue(ref jsonReader);
         }
 
diff --git a/src/HotChocolate/Core/src/Types/Utilities/ThrowHelper.cs b/src/HotChocolate/Core/src/Types/Utilities/ThrowHelper.cs
index 09b9d849d2b..3e306fd8222 100644
--- a/src/HotChocolate/Core/src/Types/Utilities/ThrowHelper.cs
+++ b/src/HotChocolate/Core/src/Types/Utilities/ThrowHelper.cs
@@ -566,4 +566,28 @@ public static SchemaException Flags_IllegalFlagEnumName(Type type, string? value
                 type.FullName ?? type.Name,
                 valueName ?? "value is null")
             .Build());
+
+    public static SchemaException InputTypeExpected(IType type)
+    {
+        var namedType = type.NamedType();
+
+        return new SchemaException(
+            SchemaErrorBuilder.New()
+                .SetMessage(ThrowHelper_InputTypeExpected_Message, namedType.Name)
+                .SetTypeSystemObject((ITypeSystemObject)namedType)
+                .SetExtension("type", type.Print())
+                .Build());
+    }
+
+    public static SchemaException OutputTypeExpected(IType type)
+    {
+        var namedType = type.NamedType();
+
+        return new SchemaException(
+            SchemaErrorBuilder.New()
+                .SetMessage(ThrowHelper_OutputTypeExpected_Message, namedType.Name)
+                .SetTypeSystemObject((ITypeSystemObject)namedType)
+                .SetExtension("type", type.Print())
+                .Build());
+    }
 }
diff --git a/src/HotChocolate/Core/test/Types.Tests/Configuration/TypeDiscoveryHandlerTests.cs b/src/HotChocolate/Core/test/Types.Tests/Configuration/TypeDiscoveryHandlerTests.cs
new file mode 100644
index 00000000000..0695dd94bbb
--- /dev/null
+++ b/src/HotChocolate/Core/test/Types.Tests/Configuration/TypeDiscoveryHandlerTests.cs
@@ -0,0 +1,51 @@
+using System.Threading.Tasks;
+using CookieCrumble;
+using HotChocolate.Execution;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace HotChocolate.Configuration;
+
+public class TypeDiscoveryHandlerTests
+{
+    // https://github.com/ChilliCream/graphql-platform/issues/5942
+    [Fact]
+    public async Task Ensure_Inputs_Are_Not_Used_As_Outputs()
+    {
+        var schema =
+            await new ServiceCollection()
+                .AddGraphQLServer()
+                .AddQueryType<Query>()
+                .AddType<Foo>()
+                .BuildSchemaAsync();
+
+        schema.MatchInlineSnapshot(
+            """
+            schema {
+              query: Query
+            }
+
+            type Query {
+              foo(foo: TestMeInput): TestMe
+            }
+
+            type TestMe {
+              bar: String
+            }
+
+            input TestMeInput {
+              bar: String
+            }
+            """);
+    }
+
+    public class Query
+    {
+        public Foo GetFoo(Foo foo) => foo;
+    }
+
+    [GraphQLName("TestMe")]
+    public class Foo
+    {
+        public string Bar { get; set; }
+    }
+}
diff --git a/src/HotChocolate/Core/test/Types.Tests/Configuration/__snapshots__/TypeDiscovererTests.Register_SchemaType_ClrTypeExists_NoSystemTypes.snap b/src/HotChocolate/Core/test/Types.Tests/Configuration/__snapshots__/TypeDiscovererTests.Register_SchemaType_ClrTypeExists_NoSystemTypes.snap
index 6cb82dfde24..85aca2e192f 100644
--- a/src/HotChocolate/Core/test/Types.Tests/Configuration/__snapshots__/TypeDiscovererTests.Register_SchemaType_ClrTypeExists_NoSystemTypes.snap
+++ b/src/HotChocolate/Core/test/Types.Tests/Configuration/__snapshots__/TypeDiscovererTests.Register_SchemaType_ClrTypeExists_NoSystemTypes.snap
@@ -30,6 +30,6 @@
   "runtimeTypeRefs": {
     "Foo (Output)": "HotChocolate.Configuration.TypeDiscovererTests+FooType (Output)",
     "Bar (Output)": "HotChocolate.Configuration.TypeDiscovererTests+BarType (Output)",
-    "String (Output)": "StringType"
+    "String": "StringType"
   }
 }
diff --git a/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_08_Single_Mutation.snap b/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_08_Single_Mutation.snap
index f21f7c0ae7a..2f9e5943a51 100644
--- a/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_08_Single_Mutation.snap
+++ b/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_08_Single_Mutation.snap
@@ -23,7 +23,7 @@ QueryPlan
       {
         "type": "Resolve",
         "subgraph": "Reviews",
-        "document": "query AddReview_1 { addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { name } } } }",
+        "document": "mutation AddReview_1 { addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { name } } } }",
         "selectionSetId": 0
       },
       {
diff --git a/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_09_Two_Mutation_Same_SubGraph.snap b/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_09_Two_Mutation_Same_SubGraph.snap
index b8ac1d66ae4..9055d4dd9b4 100644
--- a/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_09_Two_Mutation_Same_SubGraph.snap
+++ b/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_09_Two_Mutation_Same_SubGraph.snap
@@ -31,7 +31,7 @@ QueryPlan
       {
         "type": "Resolve",
         "subgraph": "Reviews",
-        "document": "query AddReviews_1 { a: addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { name } } } b: addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { name } } } }",
+        "document": "mutation AddReviews_1 { a: addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { name } } } b: addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { name } } } }",
         "selectionSetId": 0
       },
       {
diff --git a/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_10_Two_Mutation_Same_SubGraph.snap b/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_10_Two_Mutation_Same_SubGraph.snap
index f6acff7f913..d01ba310d7a 100644
--- a/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_10_Two_Mutation_Same_SubGraph.snap
+++ b/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_10_Two_Mutation_Same_SubGraph.snap
@@ -32,7 +32,7 @@ QueryPlan
       {
         "type": "Resolve",
         "subgraph": "Reviews",
-        "document": "query AddReviews_1 { a: addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { __fusion_exports__1: id } } } b: addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { id __fusion_exports__2: id } } } }",
+        "document": "mutation AddReviews_1 { a: addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { __fusion_exports__1: id } } } b: addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { id __fusion_exports__2: id } } } }",
         "selectionSetId": 0
       },
       {
diff --git a/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_11_Two_Mutation_Two_SubGraph.snap b/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_11_Two_Mutation_Two_SubGraph.snap
index 22179cb63c1..078169b9ada 100644
--- a/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_11_Two_Mutation_Two_SubGraph.snap
+++ b/src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_11_Two_Mutation_Two_SubGraph.snap
@@ -32,7 +32,7 @@ QueryPlan
       {
         "type": "Resolve",
         "subgraph": "Reviews",
-        "document": "query AddReviewAndUser_1 { addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { id __fusion_exports__1: id } } } }",
+        "document": "mutation AddReviewAndUser_1 { addReview(input: { body: \u0022foo\u0022, authorId: 1, upc: 1 }) { review { body author { id __fusion_exports__1: id } } } }",
         "selectionSetId": 0
       },
       {
@@ -44,7 +44,7 @@ QueryPlan
       {
         "type": "Resolve",
         "subgraph": "Accounts",
-        "document": "query AddReviewAndUser_2 { addUser(input: { name: \u0022foo\u0022, username: \u0022foo\u0022, birthdate: \u0022abc\u0022 }) { user { name } } }",
+        "document": "mutation AddReviewAndUser_2 { addUser(input: { name: \u0022foo\u0022, username: \u0022foo\u0022, birthdate: \u0022abc\u0022 }) { user { name } } }",
         "selectionSetId": 0
       },
       {