diff --git a/TUnit.Mocks.SourceGenerator.Tests/MockGeneratorTests.cs b/TUnit.Mocks.SourceGenerator.Tests/MockGeneratorTests.cs
index bd059cadec..e74f80f115 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/MockGeneratorTests.cs
+++ b/TUnit.Mocks.SourceGenerator.Tests/MockGeneratorTests.cs
@@ -415,4 +415,32 @@ void M()
 
         return VerifyGeneratorOutput(source);
     }
+
+    [Test]
+    public Task Interface_With_Nullable_Reference_Type_Parameters()
+    {
+        var source = """
+            using TUnit.Mocks;
+            using System.Threading.Tasks;
+
+            public interface IFoo
+            {
+                void Bar(object? baz);
+                string? GetValue(string? key, int count);
+                void Process(string nonNull, string? nullable, object? obj);
+                Task<string?> GetAsync(string? key);
+                string? NullableProp { get; set; }
+            }
+
+            public class TestUsage
+            {
+                void M()
+                {
+                    var mock = Mock.Of<IFoo>();
+                }
+            }
+            """;
+
+        return VerifyGeneratorOutput(source);
+    }
 }
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Nullable_Reference_Type_Parameters.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Nullable_Reference_Type_Parameters.verified.txt
new file mode 100644
index 0000000000..1b42ee5f1b
--- /dev/null
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Nullable_Reference_Type_Parameters.verified.txt
@@ -0,0 +1,542 @@
+// <auto-generated/>
+#nullable enable
+
+namespace TUnit.Mocks.Generated
+{
+    internal static class IFoo_MockFactory
+    {
+        [global::System.Runtime.CompilerServices.ModuleInitializer]
+        internal static void Register()
+        {
+            global::TUnit.Mocks.Mock.RegisterFactory<global::IFoo>(Create);
+        }
+
+        private static global::TUnit.Mocks.Mock<global::IFoo> Create(global::TUnit.Mocks.MockBehavior behavior)
+        {
+            var engine = new global::TUnit.Mocks.MockEngine<global::IFoo>(behavior);
+            var impl = new IFoo_MockImpl(engine);
+            engine.Raisable = impl;
+            var mock = new global::TUnit.Mocks.Mock<global::IFoo>(impl, engine);
+            return mock;
+        }
+    }
+}
+
+
+// ===== FILE SEPARATOR =====
+
+// <auto-generated/>
+#nullable enable
+
+namespace TUnit.Mocks.Generated
+{
+    internal sealed class IFoo_MockImpl : global::IFoo, global::TUnit.Mocks.IRaisable
+    {
+        private readonly global::TUnit.Mocks.MockEngine<global::IFoo> _engine;
+
+        internal IFoo_MockImpl(global::TUnit.Mocks.MockEngine<global::IFoo> engine)
+        {
+            _engine = engine;
+        }
+
+        public void Bar(object? baz)
+        {
+            _engine.HandleCall(0, "Bar", new object?[] { baz });
+        }
+
+        public string? GetValue(string? key, int count)
+        {
+            return _engine.HandleCallWithReturn<string?>(1, "GetValue", new object?[] { key, count }, default);
+        }
+
+        public void Process(string nonNull, string? nullable, object? obj)
+        {
+            _engine.HandleCall(2, "Process", new object?[] { nonNull, nullable, obj });
+        }
+
+        public global::System.Threading.Tasks.Task<string?> GetAsync(string? key)
+        {
+            try
+            {
+                var __result = _engine.HandleCallWithReturn<string?>(3, "GetAsync", new object?[] { key }, default);
+                return global::System.Threading.Tasks.Task.FromResult<string?>(__result);
+            }
+            catch (global::System.Exception __ex)
+            {
+                return global::System.Threading.Tasks.Task.FromException<string?>(__ex);
+            }
+        }
+
+        public string? NullableProp
+        {
+            get => _engine.HandleCallWithReturn<string?>(4, "get_NullableProp", global::System.Array.Empty<object?>(), default);
+            set => _engine.HandleCall(5, "set_NullableProp", new object?[] { value });
+        }
+
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public void RaiseEvent(string eventName, object? args)
+        {
+            throw new global::System.InvalidOperationException($"No event named '{eventName}' exists on this mock.");
+        }
+    }
+}
+
+
+// ===== FILE SEPARATOR =====
+
+// <auto-generated/>
+#nullable enable
+
+namespace TUnit.Mocks.Generated
+{
+    public static class IFoo_MockMemberExtensions
+    {
+        public static IFoo_Bar_M0_MockCall Bar(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::TUnit.Mocks.Arguments.Arg<object?> baz)
+        {
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { baz.Matcher };
+            return new IFoo_Bar_M0_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 0, "Bar", matchers);
+        }
+
+        public static IFoo_Bar_M0_MockCall Bar(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::System.Func<object?, bool> baz)
+        {
+            global::TUnit.Mocks.Arguments.Arg<object?> __fa_baz = baz;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { __fa_baz.Matcher };
+            return new IFoo_Bar_M0_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 0, "Bar", matchers);
+        }
+
+        public static IFoo_GetValue_M1_MockCall GetValue(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::TUnit.Mocks.Arguments.Arg<string?> key, global::TUnit.Mocks.Arguments.Arg<int> count)
+        {
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { key.Matcher, count.Matcher };
+            return new IFoo_GetValue_M1_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 1, "GetValue", matchers);
+        }
+
+        public static IFoo_GetValue_M1_MockCall GetValue(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::System.Func<string?, bool> key, global::TUnit.Mocks.Arguments.Arg<int> count)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string?> __fa_key = key;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { __fa_key.Matcher, count.Matcher };
+            return new IFoo_GetValue_M1_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 1, "GetValue", matchers);
+        }
+
+        public static IFoo_GetValue_M1_MockCall GetValue(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::TUnit.Mocks.Arguments.Arg<string?> key, global::System.Func<int, bool> count)
+        {
+            global::TUnit.Mocks.Arguments.Arg<int> __fa_count = count;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { key.Matcher, __fa_count.Matcher };
+            return new IFoo_GetValue_M1_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 1, "GetValue", matchers);
+        }
+
+        public static IFoo_GetValue_M1_MockCall GetValue(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::System.Func<string?, bool> key, global::System.Func<int, bool> count)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string?> __fa_key = key;
+            global::TUnit.Mocks.Arguments.Arg<int> __fa_count = count;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { __fa_key.Matcher, __fa_count.Matcher };
+            return new IFoo_GetValue_M1_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 1, "GetValue", matchers);
+        }
+
+        public static IFoo_Process_M2_MockCall Process(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::TUnit.Mocks.Arguments.Arg<string> nonNull, global::TUnit.Mocks.Arguments.Arg<string?> nullable, global::TUnit.Mocks.Arguments.Arg<object?> obj)
+        {
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { nonNull.Matcher, nullable.Matcher, obj.Matcher };
+            return new IFoo_Process_M2_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 2, "Process", matchers);
+        }
+
+        public static IFoo_Process_M2_MockCall Process(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::System.Func<string, bool> nonNull, global::TUnit.Mocks.Arguments.Arg<string?> nullable, global::TUnit.Mocks.Arguments.Arg<object?> obj)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string> __fa_nonNull = nonNull;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { __fa_nonNull.Matcher, nullable.Matcher, obj.Matcher };
+            return new IFoo_Process_M2_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 2, "Process", matchers);
+        }
+
+        public static IFoo_Process_M2_MockCall Process(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::TUnit.Mocks.Arguments.Arg<string> nonNull, global::System.Func<string?, bool> nullable, global::TUnit.Mocks.Arguments.Arg<object?> obj)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string?> __fa_nullable = nullable;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { nonNull.Matcher, __fa_nullable.Matcher, obj.Matcher };
+            return new IFoo_Process_M2_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 2, "Process", matchers);
+        }
+
+        public static IFoo_Process_M2_MockCall Process(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::System.Func<string, bool> nonNull, global::System.Func<string?, bool> nullable, global::TUnit.Mocks.Arguments.Arg<object?> obj)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string> __fa_nonNull = nonNull;
+            global::TUnit.Mocks.Arguments.Arg<string?> __fa_nullable = nullable;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { __fa_nonNull.Matcher, __fa_nullable.Matcher, obj.Matcher };
+            return new IFoo_Process_M2_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 2, "Process", matchers);
+        }
+
+        public static IFoo_Process_M2_MockCall Process(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::TUnit.Mocks.Arguments.Arg<string> nonNull, global::TUnit.Mocks.Arguments.Arg<string?> nullable, global::System.Func<object?, bool> obj)
+        {
+            global::TUnit.Mocks.Arguments.Arg<object?> __fa_obj = obj;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { nonNull.Matcher, nullable.Matcher, __fa_obj.Matcher };
+            return new IFoo_Process_M2_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 2, "Process", matchers);
+        }
+
+        public static IFoo_Process_M2_MockCall Process(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::System.Func<string, bool> nonNull, global::TUnit.Mocks.Arguments.Arg<string?> nullable, global::System.Func<object?, bool> obj)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string> __fa_nonNull = nonNull;
+            global::TUnit.Mocks.Arguments.Arg<object?> __fa_obj = obj;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { __fa_nonNull.Matcher, nullable.Matcher, __fa_obj.Matcher };
+            return new IFoo_Process_M2_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 2, "Process", matchers);
+        }
+
+        public static IFoo_Process_M2_MockCall Process(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::TUnit.Mocks.Arguments.Arg<string> nonNull, global::System.Func<string?, bool> nullable, global::System.Func<object?, bool> obj)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string?> __fa_nullable = nullable;
+            global::TUnit.Mocks.Arguments.Arg<object?> __fa_obj = obj;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { nonNull.Matcher, __fa_nullable.Matcher, __fa_obj.Matcher };
+            return new IFoo_Process_M2_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 2, "Process", matchers);
+        }
+
+        public static IFoo_Process_M2_MockCall Process(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::System.Func<string, bool> nonNull, global::System.Func<string?, bool> nullable, global::System.Func<object?, bool> obj)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string> __fa_nonNull = nonNull;
+            global::TUnit.Mocks.Arguments.Arg<string?> __fa_nullable = nullable;
+            global::TUnit.Mocks.Arguments.Arg<object?> __fa_obj = obj;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { __fa_nonNull.Matcher, __fa_nullable.Matcher, __fa_obj.Matcher };
+            return new IFoo_Process_M2_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 2, "Process", matchers);
+        }
+
+        public static IFoo_GetAsync_M3_MockCall GetAsync(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::TUnit.Mocks.Arguments.Arg<string?> key)
+        {
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { key.Matcher };
+            return new IFoo_GetAsync_M3_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 3, "GetAsync", matchers);
+        }
+
+        public static IFoo_GetAsync_M3_MockCall GetAsync(this global::TUnit.Mocks.Mock<global::IFoo> mock, global::System.Func<string?, bool> key)
+        {
+            global::TUnit.Mocks.Arguments.Arg<string?> __fa_key = key;
+            var matchers = new global::TUnit.Mocks.Arguments.IArgumentMatcher[] { __fa_key.Matcher };
+            return new IFoo_GetAsync_M3_MockCall(global::TUnit.Mocks.Mock.GetEngine(mock), 3, "GetAsync", matchers);
+        }
+
+        extension(global::TUnit.Mocks.Mock<global::IFoo> mock)
+        {
+            public global::TUnit.Mocks.PropertyMockCall<string?> NullableProp
+                => new(global::TUnit.Mocks.Mock.GetEngine(mock), 4, 5, "NullableProp", true, true);
+        }
+    }
+
+    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+    public sealed class IFoo_Bar_M0_MockCall : global::TUnit.Mocks.Verification.ICallVerification
+    {
+        private readonly global::TUnit.Mocks.IMockEngineAccess _engine;
+        private readonly int _memberId;
+        private readonly string _memberName;
+        private readonly global::TUnit.Mocks.Arguments.IArgumentMatcher[] _matchers;
+        private readonly global::System.Lazy<global::TUnit.Mocks.Setup.VoidMethodSetupBuilder> _lazyBuilder;
+
+        internal IFoo_Bar_M0_MockCall(global::TUnit.Mocks.IMockEngineAccess engine, int memberId, string memberName, global::TUnit.Mocks.Arguments.IArgumentMatcher[] matchers)
+        {
+            _engine = engine;
+            _memberId = memberId;
+            _memberName = memberName;
+            _matchers = matchers;
+            _lazyBuilder = new global::System.Lazy<global::TUnit.Mocks.Setup.VoidMethodSetupBuilder>(() =>
+            {
+                var setup = new global::TUnit.Mocks.Setup.MethodSetup(_memberId, _matchers, _memberName);
+                _engine.AddSetup(setup);
+                return new global::TUnit.Mocks.Setup.VoidMethodSetupBuilder(setup);
+            }
+            );
+            _ = _lazyBuilder.Value;
+        }
+
+        private global::TUnit.Mocks.Setup.VoidMethodSetupBuilder EnsureSetup() => _lazyBuilder.Value;
+
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall Throws<TException>() where TException : global::System.Exception, new() { EnsureSetup().Throws<TException>(); return this; }
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall Throws(global::System.Exception exception) { EnsureSetup().Throws(exception); return this; }
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall Callback(global::System.Action callback) { EnsureSetup().Callback(callback); return this; }
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall Callback(global::System.Action<object?[]> callback) { EnsureSetup().Callback(callback); return this; }
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall Throws(global::System.Func<object?[], global::System.Exception> exceptionFactory) { EnsureSetup().Throws(exceptionFactory); return this; }
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall Raises(string eventName, object? args = null) { EnsureSetup().Raises(eventName, args); return this; }
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall SetsOutParameter(int paramIndex, object? value) { EnsureSetup().SetsOutParameter(paramIndex, value); return this; }
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall TransitionsTo(string stateName) { EnsureSetup().TransitionsTo(stateName); return this; }
+        /// <inheritdoc />
+        public IFoo_Bar_M0_MockCall Then() { EnsureSetup().Then(); return this; }
+
+        /// <summary>Execute a typed callback using the actual method parameters.</summary>
+        public IFoo_Bar_M0_MockCall Callback(global::System.Action<object?> callback)
+        {
+            EnsureSetup().Callback(args => callback((object?)args[0]!));
+            return this;
+        }
+
+        /// <summary>Configure a typed computed exception using the actual method parameters.</summary>
+        public IFoo_Bar_M0_MockCall Throws(global::System.Func<object?, global::System.Exception> exceptionFactory)
+        {
+            EnsureSetup().Throws(args => exceptionFactory((object?)args[0]!));
+            return this;
+        }
+
+        // ICallVerification
+        /// <inheritdoc />
+        public void WasCalled() => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled();
+        /// <inheritdoc />
+        public void WasCalled(global::TUnit.Mocks.Times times) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(times);
+        /// <inheritdoc />
+        public void WasCalled(global::TUnit.Mocks.Times times, string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(times, message);
+        /// <inheritdoc />
+        public void WasCalled(string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(message);
+        /// <inheritdoc />
+        public void WasNeverCalled() => _engine.CreateVerification(_memberId, _memberName, _matchers).WasNeverCalled();
+        /// <inheritdoc />
+        public void WasNeverCalled(string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasNeverCalled(message);
+    }
+
+    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+    public sealed class IFoo_GetValue_M1_MockCall : global::TUnit.Mocks.Verification.ICallVerification
+    {
+        private readonly global::TUnit.Mocks.IMockEngineAccess _engine;
+        private readonly int _memberId;
+        private readonly string _memberName;
+        private readonly global::TUnit.Mocks.Arguments.IArgumentMatcher[] _matchers;
+        private readonly global::System.Lazy<global::TUnit.Mocks.Setup.MethodSetupBuilder<string?>> _lazyBuilder;
+
+        internal IFoo_GetValue_M1_MockCall(global::TUnit.Mocks.IMockEngineAccess engine, int memberId, string memberName, global::TUnit.Mocks.Arguments.IArgumentMatcher[] matchers)
+        {
+            _engine = engine;
+            _memberId = memberId;
+            _memberName = memberName;
+            _matchers = matchers;
+            _lazyBuilder = new global::System.Lazy<global::TUnit.Mocks.Setup.MethodSetupBuilder<string?>>(() =>
+            {
+                var setup = new global::TUnit.Mocks.Setup.MethodSetup(_memberId, _matchers, _memberName);
+                _engine.AddSetup(setup);
+                return new global::TUnit.Mocks.Setup.MethodSetupBuilder<string?>(setup);
+            }
+            );
+        }
+
+        private global::TUnit.Mocks.Setup.MethodSetupBuilder<string?> EnsureSetup() => _lazyBuilder.Value;
+
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Returns(string? value) { EnsureSetup().Returns(value); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Returns(global::System.Func<string?> factory) { EnsureSetup().Returns(factory); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall ReturnsSequentially(params string?[] values) { EnsureSetup().ReturnsSequentially(values); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Throws<TException>() where TException : global::System.Exception, new() { EnsureSetup().Throws<TException>(); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Throws(global::System.Exception exception) { EnsureSetup().Throws(exception); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Callback(global::System.Action callback) { EnsureSetup().Callback(callback); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Callback(global::System.Action<object?[]> callback) { EnsureSetup().Callback(callback); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Returns(global::System.Func<object?[], string?> factory) { EnsureSetup().Returns(factory); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Throws(global::System.Func<object?[], global::System.Exception> exceptionFactory) { EnsureSetup().Throws(exceptionFactory); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Raises(string eventName, object? args = null) { EnsureSetup().Raises(eventName, args); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall SetsOutParameter(int paramIndex, object? value) { EnsureSetup().SetsOutParameter(paramIndex, value); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall TransitionsTo(string stateName) { EnsureSetup().TransitionsTo(stateName); return this; }
+        /// <inheritdoc />
+        public IFoo_GetValue_M1_MockCall Then() { EnsureSetup().Then(); return this; }
+
+        /// <summary>Configure a typed computed return value using the actual method parameters.</summary>
+        public IFoo_GetValue_M1_MockCall Returns(global::System.Func<string?, int, string?> factory)
+        {
+            EnsureSetup().Returns(args => factory((string?)args[0]!, (int)args[1]!));
+            return this;
+        }
+
+        /// <summary>Execute a typed callback using the actual method parameters.</summary>
+        public IFoo_GetValue_M1_MockCall Callback(global::System.Action<string?, int> callback)
+        {
+            EnsureSetup().Callback(args => callback((string?)args[0]!, (int)args[1]!));
+            return this;
+        }
+
+        /// <summary>Configure a typed computed exception using the actual method parameters.</summary>
+        public IFoo_GetValue_M1_MockCall Throws(global::System.Func<string?, int, global::System.Exception> exceptionFactory)
+        {
+            EnsureSetup().Throws(args => exceptionFactory((string?)args[0]!, (int)args[1]!));
+            return this;
+        }
+
+        // ICallVerification
+        /// <inheritdoc />
+        public void WasCalled() => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled();
+        /// <inheritdoc />
+        public void WasCalled(global::TUnit.Mocks.Times times) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(times);
+        /// <inheritdoc />
+        public void WasCalled(global::TUnit.Mocks.Times times, string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(times, message);
+        /// <inheritdoc />
+        public void WasCalled(string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(message);
+        /// <inheritdoc />
+        public void WasNeverCalled() => _engine.CreateVerification(_memberId, _memberName, _matchers).WasNeverCalled();
+        /// <inheritdoc />
+        public void WasNeverCalled(string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasNeverCalled(message);
+    }
+
+    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+    public sealed class IFoo_Process_M2_MockCall : global::TUnit.Mocks.Verification.ICallVerification
+    {
+        private readonly global::TUnit.Mocks.IMockEngineAccess _engine;
+        private readonly int _memberId;
+        private readonly string _memberName;
+        private readonly global::TUnit.Mocks.Arguments.IArgumentMatcher[] _matchers;
+        private readonly global::System.Lazy<global::TUnit.Mocks.Setup.VoidMethodSetupBuilder> _lazyBuilder;
+
+        internal IFoo_Process_M2_MockCall(global::TUnit.Mocks.IMockEngineAccess engine, int memberId, string memberName, global::TUnit.Mocks.Arguments.IArgumentMatcher[] matchers)
+        {
+            _engine = engine;
+            _memberId = memberId;
+            _memberName = memberName;
+            _matchers = matchers;
+            _lazyBuilder = new global::System.Lazy<global::TUnit.Mocks.Setup.VoidMethodSetupBuilder>(() =>
+            {
+                var setup = new global::TUnit.Mocks.Setup.MethodSetup(_memberId, _matchers, _memberName);
+                _engine.AddSetup(setup);
+                return new global::TUnit.Mocks.Setup.VoidMethodSetupBuilder(setup);
+            }
+            );
+            _ = _lazyBuilder.Value;
+        }
+
+        private global::TUnit.Mocks.Setup.VoidMethodSetupBuilder EnsureSetup() => _lazyBuilder.Value;
+
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall Throws<TException>() where TException : global::System.Exception, new() { EnsureSetup().Throws<TException>(); return this; }
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall Throws(global::System.Exception exception) { EnsureSetup().Throws(exception); return this; }
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall Callback(global::System.Action callback) { EnsureSetup().Callback(callback); return this; }
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall Callback(global::System.Action<object?[]> callback) { EnsureSetup().Callback(callback); return this; }
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall Throws(global::System.Func<object?[], global::System.Exception> exceptionFactory) { EnsureSetup().Throws(exceptionFactory); return this; }
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall Raises(string eventName, object? args = null) { EnsureSetup().Raises(eventName, args); return this; }
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall SetsOutParameter(int paramIndex, object? value) { EnsureSetup().SetsOutParameter(paramIndex, value); return this; }
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall TransitionsTo(string stateName) { EnsureSetup().TransitionsTo(stateName); return this; }
+        /// <inheritdoc />
+        public IFoo_Process_M2_MockCall Then() { EnsureSetup().Then(); return this; }
+
+        /// <summary>Execute a typed callback using the actual method parameters.</summary>
+        public IFoo_Process_M2_MockCall Callback(global::System.Action<string, string?, object?> callback)
+        {
+            EnsureSetup().Callback(args => callback((string)args[0]!, (string?)args[1]!, (object?)args[2]!));
+            return this;
+        }
+
+        /// <summary>Configure a typed computed exception using the actual method parameters.</summary>
+        public IFoo_Process_M2_MockCall Throws(global::System.Func<string, string?, object?, global::System.Exception> exceptionFactory)
+        {
+            EnsureSetup().Throws(args => exceptionFactory((string)args[0]!, (string?)args[1]!, (object?)args[2]!));
+            return this;
+        }
+
+        // ICallVerification
+        /// <inheritdoc />
+        public void WasCalled() => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled();
+        /// <inheritdoc />
+        public void WasCalled(global::TUnit.Mocks.Times times) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(times);
+        /// <inheritdoc />
+        public void WasCalled(global::TUnit.Mocks.Times times, string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(times, message);
+        /// <inheritdoc />
+        public void WasCalled(string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(message);
+        /// <inheritdoc />
+        public void WasNeverCalled() => _engine.CreateVerification(_memberId, _memberName, _matchers).WasNeverCalled();
+        /// <inheritdoc />
+        public void WasNeverCalled(string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasNeverCalled(message);
+    }
+
+    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+    public sealed class IFoo_GetAsync_M3_MockCall : global::TUnit.Mocks.Verification.ICallVerification
+    {
+        private readonly global::TUnit.Mocks.IMockEngineAccess _engine;
+        private readonly int _memberId;
+        private readonly string _memberName;
+        private readonly global::TUnit.Mocks.Arguments.IArgumentMatcher[] _matchers;
+        private readonly global::System.Lazy<global::TUnit.Mocks.Setup.MethodSetupBuilder<string?>> _lazyBuilder;
+
+        internal IFoo_GetAsync_M3_MockCall(global::TUnit.Mocks.IMockEngineAccess engine, int memberId, string memberName, global::TUnit.Mocks.Arguments.IArgumentMatcher[] matchers)
+        {
+            _engine = engine;
+            _memberId = memberId;
+            _memberName = memberName;
+            _matchers = matchers;
+            _lazyBuilder = new global::System.Lazy<global::TUnit.Mocks.Setup.MethodSetupBuilder<string?>>(() =>
+            {
+                var setup = new global::TUnit.Mocks.Setup.MethodSetup(_memberId, _matchers, _memberName);
+                _engine.AddSetup(setup);
+                return new global::TUnit.Mocks.Setup.MethodSetupBuilder<string?>(setup);
+            }
+            );
+        }
+
+        private global::TUnit.Mocks.Setup.MethodSetupBuilder<string?> EnsureSetup() => _lazyBuilder.Value;
+
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Returns(string? value) { EnsureSetup().Returns(value); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Returns(global::System.Func<string?> factory) { EnsureSetup().Returns(factory); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall ReturnsSequentially(params string?[] values) { EnsureSetup().ReturnsSequentially(values); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Throws<TException>() where TException : global::System.Exception, new() { EnsureSetup().Throws<TException>(); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Throws(global::System.Exception exception) { EnsureSetup().Throws(exception); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Callback(global::System.Action callback) { EnsureSetup().Callback(callback); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Callback(global::System.Action<object?[]> callback) { EnsureSetup().Callback(callback); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Returns(global::System.Func<object?[], string?> factory) { EnsureSetup().Returns(factory); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Throws(global::System.Func<object?[], global::System.Exception> exceptionFactory) { EnsureSetup().Throws(exceptionFactory); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Raises(string eventName, object? args = null) { EnsureSetup().Raises(eventName, args); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall SetsOutParameter(int paramIndex, object? value) { EnsureSetup().SetsOutParameter(paramIndex, value); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall TransitionsTo(string stateName) { EnsureSetup().TransitionsTo(stateName); return this; }
+        /// <inheritdoc />
+        public IFoo_GetAsync_M3_MockCall Then() { EnsureSetup().Then(); return this; }
+
+        /// <summary>Configure a typed computed return value using the actual method parameters.</summary>
+        public IFoo_GetAsync_M3_MockCall Returns(global::System.Func<string?, string?> factory)
+        {
+            EnsureSetup().Returns(args => factory((string?)args[0]!));
+            return this;
+        }
+
+        /// <summary>Execute a typed callback using the actual method parameters.</summary>
+        public IFoo_GetAsync_M3_MockCall Callback(global::System.Action<string?> callback)
+        {
+            EnsureSetup().Callback(args => callback((string?)args[0]!));
+            return this;
+        }
+
+        /// <summary>Configure a typed computed exception using the actual method parameters.</summary>
+        public IFoo_GetAsync_M3_MockCall Throws(global::System.Func<string?, global::System.Exception> exceptionFactory)
+        {
+            EnsureSetup().Throws(args => exceptionFactory((string?)args[0]!));
+            return this;
+        }
+
+        // ICallVerification
+        /// <inheritdoc />
+        public void WasCalled() => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled();
+        /// <inheritdoc />
+        public void WasCalled(global::TUnit.Mocks.Times times) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(times);
+        /// <inheritdoc />
+        public void WasCalled(global::TUnit.Mocks.Times times, string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(times, message);
+        /// <inheritdoc />
+        public void WasCalled(string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasCalled(message);
+        /// <inheritdoc />
+        public void WasNeverCalled() => _engine.CreateVerification(_memberId, _memberName, _matchers).WasNeverCalled();
+        /// <inheritdoc />
+        public void WasNeverCalled(string? message) => _engine.CreateVerification(_memberId, _memberName, _matchers).WasNeverCalled(message);
+    }
+}
diff --git a/TUnit.Mocks.SourceGenerator/Discovery/MemberDiscovery.cs b/TUnit.Mocks.SourceGenerator/Discovery/MemberDiscovery.cs
index 7dc063b15d..7a1c5536ee 100644
--- a/TUnit.Mocks.SourceGenerator/Discovery/MemberDiscovery.cs
+++ b/TUnit.Mocks.SourceGenerator/Discovery/MemberDiscovery.cs
@@ -307,7 +307,7 @@ private static MockMemberModel CreateMethodModel(IMethodSymbol method, ref int m
         {
             Name = method.Name,
             MemberId = memberIdCounter++,
-            ReturnType = returnType.GetFullyQualifiedName(),
+            ReturnType = returnType.GetFullyQualifiedNameWithNullability(),
             UnwrappedReturnType = unwrappedType,
             IsVoid = isVoid,
             IsAsync = isAsync,
@@ -318,8 +318,8 @@ private static MockMemberModel CreateMethodModel(IMethodSymbol method, ref int m
                 method.Parameters.Select(p => new MockParameterModel
                 {
                     Name = EscapeIdentifier(p.Name),
-                    Type = p.Type.ToDisplayString(SymbolDisplayFormat.MinimallyQualifiedFormat),
-                    FullyQualifiedType = p.Type.GetFullyQualifiedName(),
+                    Type = p.Type.GetMinimallyQualifiedNameWithNullability(),
+                    FullyQualifiedType = p.Type.GetFullyQualifiedNameWithNullability(),
                     Direction = p.GetParameterDirection(),
                     HasDefaultValue = p.HasExplicitDefaultValue,
                     DefaultValueExpression = p.HasExplicitDefaultValue ? FormatDefaultValue(p) : null,
@@ -380,8 +380,8 @@ private static MockMemberModel CreatePropertyModel(IPropertySymbol property, ref
         {
             Name = property.Name,
             MemberId = getterId,
-            ReturnType = property.Type.GetFullyQualifiedName(),
-            UnwrappedReturnType = property.Type.GetFullyQualifiedName(),
+            ReturnType = property.Type.GetFullyQualifiedNameWithNullability(),
+            UnwrappedReturnType = property.Type.GetFullyQualifiedNameWithNullability(),
             IsVoid = false,
             IsAsync = false,
             IsProperty = true,
@@ -418,8 +418,8 @@ public static EquatableArray<MockConstructorModel> DiscoverConstructors(INamedTy
                     ctor.Parameters.Select(p => new MockParameterModel
                     {
                         Name = EscapeIdentifier(p.Name),
-                        Type = p.Type.ToDisplayString(SymbolDisplayFormat.MinimallyQualifiedFormat),
-                        FullyQualifiedType = p.Type.GetFullyQualifiedName(),
+                        Type = p.Type.GetMinimallyQualifiedNameWithNullability(),
+                        FullyQualifiedType = p.Type.GetFullyQualifiedNameWithNullability(),
                         Direction = p.GetParameterDirection(),
                         HasDefaultValue = p.HasExplicitDefaultValue,
                         DefaultValueExpression = p.HasExplicitDefaultValue ? FormatDefaultValue(p) : null,
@@ -443,8 +443,8 @@ private static MockMemberModel CreateIndexerModel(IPropertySymbol indexer, ref i
             Name = "this",
             MemberId = getterId,
             SetterMemberId = setterId,
-            ReturnType = indexer.Type.GetFullyQualifiedName(),
-            UnwrappedReturnType = indexer.Type.GetFullyQualifiedName(),
+            ReturnType = indexer.Type.GetFullyQualifiedNameWithNullability(),
+            UnwrappedReturnType = indexer.Type.GetFullyQualifiedNameWithNullability(),
             IsVoid = false,
             IsAsync = false,
             IsProperty = true,
@@ -455,8 +455,8 @@ private static MockMemberModel CreateIndexerModel(IPropertySymbol indexer, ref i
                 indexer.Parameters.Select(p => new MockParameterModel
                 {
                     Name = EscapeIdentifier(p.Name),
-                    Type = p.Type.ToDisplayString(SymbolDisplayFormat.MinimallyQualifiedFormat),
-                    FullyQualifiedType = p.Type.GetFullyQualifiedName(),
+                    Type = p.Type.GetMinimallyQualifiedNameWithNullability(),
+                    FullyQualifiedType = p.Type.GetFullyQualifiedNameWithNullability(),
                     Direction = ParameterDirection.In
                 }).ToImmutableArray()
             ),
@@ -513,8 +513,8 @@ private static MockEventModel CreateEventModel(IEventSymbol evt, string? explici
             raiseParams.Select(p => new MockParameterModel
             {
                 Name = EscapeIdentifier(p.Name),
-                FullyQualifiedType = p.Type.GetFullyQualifiedName(),
-                Type = p.Type.ToDisplayString(SymbolDisplayFormat.MinimallyQualifiedFormat),
+                FullyQualifiedType = p.Type.GetFullyQualifiedNameWithNullability(),
+                Type = p.Type.GetMinimallyQualifiedNameWithNullability(),
                 Direction = ParameterDirection.In
             }).ToImmutableArray());
 
diff --git a/TUnit.Mocks.SourceGenerator/Extensions/MethodSymbolExtensions.cs b/TUnit.Mocks.SourceGenerator/Extensions/MethodSymbolExtensions.cs
index ae71c1953f..7114cd0a62 100644
--- a/TUnit.Mocks.SourceGenerator/Extensions/MethodSymbolExtensions.cs
+++ b/TUnit.Mocks.SourceGenerator/Extensions/MethodSymbolExtensions.cs
@@ -54,7 +54,7 @@ public static string GetParameterList(this IMethodSymbol method)
                 RefKind.In => "in ",
                 _ => ""
             };
-            return $"{direction}{p.Type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat)} {p.Name}";
+            return $"{direction}{p.Type.GetFullyQualifiedNameWithNullability()} {p.Name}";
         }));
     }
 
diff --git a/TUnit.Mocks.SourceGenerator/Extensions/TypeSymbolExtensions.cs b/TUnit.Mocks.SourceGenerator/Extensions/TypeSymbolExtensions.cs
index 8643508e76..3bcd83fdd8 100644
--- a/TUnit.Mocks.SourceGenerator/Extensions/TypeSymbolExtensions.cs
+++ b/TUnit.Mocks.SourceGenerator/Extensions/TypeSymbolExtensions.cs
@@ -6,11 +6,30 @@ namespace TUnit.Mocks.SourceGenerator.Extensions;
 
 internal static class TypeSymbolExtensions
 {
+    private static readonly SymbolDisplayFormat FullyQualifiedWithNullability =
+        SymbolDisplayFormat.FullyQualifiedFormat.AddMiscellaneousOptions(
+            SymbolDisplayMiscellaneousOptions.IncludeNullableReferenceTypeModifier);
+
+    private static readonly SymbolDisplayFormat MinimallyQualifiedWithNullability =
+        SymbolDisplayFormat.MinimallyQualifiedFormat.AddMiscellaneousOptions(
+            SymbolDisplayMiscellaneousOptions.IncludeNullableReferenceTypeModifier);
+
+    /// <summary>
+    /// Returns the fully qualified name without nullable annotations.
+    /// For code generation that must preserve nullable reference type annotations,
+    /// use <see cref="GetFullyQualifiedNameWithNullability"/> instead.
+    /// </summary>
     public static string GetFullyQualifiedName(this ITypeSymbol type)
     {
         return type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
     }
 
+    public static string GetFullyQualifiedNameWithNullability(this ITypeSymbol type)
+        => type.ToDisplayString(FullyQualifiedWithNullability);
+
+    public static string GetMinimallyQualifiedNameWithNullability(this ITypeSymbol type)
+        => type.ToDisplayString(MinimallyQualifiedWithNullability);
+
     public static string GetFullyQualifiedNameWithoutGlobal(this ITypeSymbol type)
     {
         var fqn = type.GetFullyQualifiedName();
@@ -197,9 +216,9 @@ public static (string UnwrappedType, bool IsVoidAsync) GetUnwrappedReturnType(th
             var name = named.ConstructedFrom.Name;
             if ((name == "Task" || name == "ValueTask") && named.TypeArguments.Length == 1)
             {
-                return (named.TypeArguments[0].GetFullyQualifiedName(), false);
+                return (named.TypeArguments[0].GetFullyQualifiedNameWithNullability(), false);
             }
         }
-        return (type.GetFullyQualifiedName(), false);
+        return (type.GetFullyQualifiedNameWithNullability(), false);
     }
 }