fix(sourcegen): emit default literal for value-type assertion parameters

TUnit.Assertions.SourceGenerator.Tests/AssertionExtensionGeneratorTests.ValueTypeDefaultParameter.DotNet10_0.verified.txt

@@ -0,0 +1,32 @@
+[  
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+
+using System;
+using System.Runtime.CompilerServices;
+using TUnit.Assertions.Core;
+using TUnit.Assertions.Enums;
+using TUnit.Assertions.Tests.TestData;
+
+namespace TUnit.Assertions.Extensions;
+
+/// <summary>
+/// Generated extension methods for StringRespectsTokenAssertion.
+/// </summary>
+public static partial class StringRespectsTokenAssertionExtensions
+{
+
+    /// <summary>
+    /// Extension method for StringRespectsTokenAssertion.
+    /// </summary>
+    public static StringRespectsTokenAssertion RespectsToken(this IAssertionSource<string> source, System.Threading.CancellationToken token = default, [CallerArgumentExpression(nameof(token))] string? tokenExpression = null)
+    {
+        source.Context.ExpressionBuilder.Append(".RespectsToken(");
+        source.Context.ExpressionBuilder.Append(tokenExpression);
+        source.Context.ExpressionBuilder.Append(")");
+        return new StringRespectsTokenAssertion(source.Context, token);
+    }
+}
+
+]

TUnit.Assertions.SourceGenerator.Tests/AssertionExtensionGeneratorTests.ValueTypeDefaultParameter.DotNet8_0.verified.txt

@@ -0,0 +1,32 @@
+[  
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+
+using System;
+using System.Runtime.CompilerServices;
+using TUnit.Assertions.Core;
+using TUnit.Assertions.Enums;
+using TUnit.Assertions.Tests.TestData;
+
+namespace TUnit.Assertions.Extensions;
+
+/// <summary>
+/// Generated extension methods for StringRespectsTokenAssertion.
+/// </summary>
+public static partial class StringRespectsTokenAssertionExtensions
+{
+
+    /// <summary>
+    /// Extension method for StringRespectsTokenAssertion.
+    /// </summary>
+    public static StringRespectsTokenAssertion RespectsToken(this IAssertionSource<string> source, System.Threading.CancellationToken token = default, [CallerArgumentExpression(nameof(token))] string? tokenExpression = null)
+    {
+        source.Context.ExpressionBuilder.Append(".RespectsToken(");
+        source.Context.ExpressionBuilder.Append(tokenExpression);
+        source.Context.ExpressionBuilder.Append(")");
+        return new StringRespectsTokenAssertion(source.Context, token);
+    }
+}
+
+]

TUnit.Assertions.SourceGenerator.Tests/AssertionExtensionGeneratorTests.ValueTypeDefaultParameter.DotNet9_0.verified.txt

@@ -0,0 +1,32 @@
+[  
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+
+using System;
+using System.Runtime.CompilerServices;
+using TUnit.Assertions.Core;
+using TUnit.Assertions.Enums;
+using TUnit.Assertions.Tests.TestData;
+
+namespace TUnit.Assertions.Extensions;
+
+/// <summary>
+/// Generated extension methods for StringRespectsTokenAssertion.
+/// </summary>
+public static partial class StringRespectsTokenAssertionExtensions
+{
+
+    /// <summary>
+    /// Extension method for StringRespectsTokenAssertion.
+    /// </summary>
+    public static StringRespectsTokenAssertion RespectsToken(this IAssertionSource<string> source, System.Threading.CancellationToken token = default, [CallerArgumentExpression(nameof(token))] string? tokenExpression = null)
+    {
+        source.Context.ExpressionBuilder.Append(".RespectsToken(");
+        source.Context.ExpressionBuilder.Append(tokenExpression);
+        source.Context.ExpressionBuilder.Append(")");
+        return new StringRespectsTokenAssertion(source.Context, token);
+    }
+}
+
+]

TUnit.Assertions.SourceGenerator.Tests/AssertionExtensionGeneratorTests.ValueTypeDefaultParameter.Net4_7.verified.txt

@@ -0,0 +1,32 @@
+[  
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+
+using System;
+using System.Runtime.CompilerServices;
+using TUnit.Assertions.Core;
+using TUnit.Assertions.Enums;
+using TUnit.Assertions.Tests.TestData;
+
+namespace TUnit.Assertions.Extensions;
+
+/// <summary>
+/// Generated extension methods for StringRespectsTokenAssertion.
+/// </summary>
+public static partial class StringRespectsTokenAssertionExtensions
+{
+
+    /// <summary>
+    /// Extension method for StringRespectsTokenAssertion.
+    /// </summary>
+    public static StringRespectsTokenAssertion RespectsToken(this IAssertionSource<string> source, System.Threading.CancellationToken token = default, [CallerArgumentExpression(nameof(token))] string? tokenExpression = null)
+    {
+        source.Context.ExpressionBuilder.Append(".RespectsToken(");
+        source.Context.ExpressionBuilder.Append(tokenExpression);
+        source.Context.ExpressionBuilder.Append(")");
+        return new StringRespectsTokenAssertion(source.Context, token);
+    }
+}
+
+]

TUnit.Assertions.SourceGenerator.Tests/AssertionExtensionGeneratorTests.cs

@@ -210,4 +210,27 @@ public Task AssertionWithMultipleParameters() => RunTest(
             var callerExprCount = System.Text.RegularExpressions.Regex.Matches(extensionFile!, "CallerArgumentExpression").Count;
             await Assert.That(callerExprCount).IsGreaterThanOrEqualTo(2);
         });
+
+    [Test]
+    public Task ValueTypeDefaultParameter() => RunTest(
+        Path.Combine(Sourcy.Git.RootDirectory.FullName,
+            "TUnit.Assertions.SourceGenerator.Tests",
+            "TestData",
+            "AssertionExtensionValueTypeDefaultParameterAssertion.cs"),
+        async generatedFiles =>
+        {
+            await Assert.That(generatedFiles).Count().IsEqualTo(1);
+
+            var extensionFile = generatedFiles.First();
+            await Assert.That(extensionFile).IsNotNull();
+
+            // A non-nullable value-type constructor parameter declared with `= default` must
+            // render as the bare `default` literal, not `= null`. The literal `null` is invalid
+            // for a non-nullable value type and produces CS1750. The trailing comma anchors the
+            // assertion to bare `default`, ruling out the longer `default(TypeName)` form.
+            await Assert.That(extensionFile).Contains("CancellationToken token = default,");
+            await Assert.That(extensionFile).DoesNotContain("CancellationToken token = null");
+
+            await CompileChecker.AssertNoErrors(generatedFiles);
+        });
 }

TUnit.Assertions.SourceGenerator.Tests/CompileChecker.cs

@@ -0,0 +1,43 @@
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+
+namespace TUnit.Assertions.SourceGenerator.Tests;
+
+/// <summary>
+/// Parses generator output as C# and asserts there are no error-severity diagnostics.
+/// Pins the entire class of source-generator emit bugs (mis-paired brackets, wrong
+/// default-value rendering, invalid generic parameter lists) regardless of the specific
+/// diagnostic id. Use alongside content-shape assertions when the test wants both a
+/// targeted regression check and a structural compile-clean gate.
+/// </summary>
+internal static class CompileChecker
+{
+    public static async Task AssertNoErrors(IEnumerable<string> generatedFiles)
+    {
+        var trees = generatedFiles
+            .Select(source => CSharpSyntaxTree.ParseText(source))
+            .ToArray();
+
+        var compilation = CSharpCompilation.Create(
+            "CompileCheck",
+            trees,
+            ReferencesHelper.References,
+            new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
+
+        // On the net472 leg of CI, the Polyfill assembly's CallerArgumentExpressionAttribute
+        // is declared internal, which produces a CS0122 ('inaccessible due to its protection
+        // level') false positive when Roslyn compiles the generator's output through the test
+        // project's reference set. Filter CS0122 only on net472; the emit shape is still
+        // pinned by the `.Net4_7` snapshot files. On modern TFMs the BCL attribute is public,
+        // so CS0122 (if it ever appears) would be a genuine signal and is not filtered.
+        var errors = compilation.GetDiagnostics()
+            .Where(d => d.Severity == DiagnosticSeverity.Error)
+#if NETFRAMEWORK
+            .Where(d => !string.Equals(d.Id, "CS0122", System.StringComparison.Ordinal))
+#endif
+            .Select(d => $"{d.Id}: {d.GetMessage()}")
+            .ToArray();
+
+        await Assert.That(errors).IsEmpty();
+    }
+}

TUnit.Assertions.SourceGenerator.Tests/MethodAssertionGeneratorTests.ValueTypeDefaultParameter.DotNet10_0.verified.txt

@@ -0,0 +1,64 @@
+[  
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+
+using System;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+using TUnit.Assertions.Core;
+using TUnit.Assertions.Tests.TestData;
+
+namespace TUnit.Assertions.Extensions;
+
+/// <summary>
+/// Generated assertion for RespectsToken
+/// </summary>
+public sealed class Int_RespectsToken_CancellationToken_Assertion : Assertion<int>
+{
+    private static readonly Task<AssertionResult> _passedTask = Task.FromResult(AssertionResult.Passed);
+
+    private readonly System.Threading.CancellationToken _token;
+
+    public Int_RespectsToken_CancellationToken_Assertion(AssertionContext<int> context, System.Threading.CancellationToken token)
+        : base(context)
+    {
+        _token = token;
+    }
+
+    protected override Task<AssertionResult> CheckAsync(EvaluationMetadata<int> metadata)
+    {
+        var value = metadata.Value;
+        var exception = metadata.Exception;
+
+        if (exception != null)
+        {
+            return Task.FromResult(AssertionResult.Failed($"threw {exception.GetType().FullName}"));
+        }
+
+        var result = value!.RespectsToken(_token);
+        return result
+            ? _passedTask
+            : Task.FromResult(AssertionResult.Failed($"found {value}"));
+    }
+
+    protected override string GetExpectation()
+    {
+        return $"to satisfy RespectsToken({_token})";
+    }
+}
+
+public static partial class ValueTypeDefaultParameterAssertionExtensions
+{
+    /// <summary>
+    /// Generated extension method for RespectsToken
+    /// </summary>
+    public static Int_RespectsToken_CancellationToken_Assertion RespectsToken(this IAssertionSource<int> source, System.Threading.CancellationToken token = default, [CallerArgumentExpression(nameof(token))] string? tokenExpression = null)
+    {
+        source.Context.ExpressionBuilder.Append($".RespectsToken({tokenExpression})");
+        return new Int_RespectsToken_CancellationToken_Assertion(source.Context, token);
+    }
+
+}
+
+]

TUnit.Assertions.SourceGenerator.Tests/MethodAssertionGeneratorTests.ValueTypeDefaultParameter.DotNet8_0.verified.txt

@@ -0,0 +1,64 @@
+[  
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+
+using System;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+using TUnit.Assertions.Core;
+using TUnit.Assertions.Tests.TestData;
+
+namespace TUnit.Assertions.Extensions;
+
+/// <summary>
+/// Generated assertion for RespectsToken
+/// </summary>
+public sealed class Int_RespectsToken_CancellationToken_Assertion : Assertion<int>
+{
+    private static readonly Task<AssertionResult> _passedTask = Task.FromResult(AssertionResult.Passed);
+
+    private readonly System.Threading.CancellationToken _token;
+
+    public Int_RespectsToken_CancellationToken_Assertion(AssertionContext<int> context, System.Threading.CancellationToken token)
+        : base(context)
+    {
+        _token = token;
+    }
+
+    protected override Task<AssertionResult> CheckAsync(EvaluationMetadata<int> metadata)
+    {
+        var value = metadata.Value;
+        var exception = metadata.Exception;
+
+        if (exception != null)
+        {
+            return Task.FromResult(AssertionResult.Failed($"threw {exception.GetType().FullName}"));
+        }
+
+        var result = value!.RespectsToken(_token);
+        return result
+            ? _passedTask
+            : Task.FromResult(AssertionResult.Failed($"found {value}"));
+    }
+
+    protected override string GetExpectation()
+    {
+        return $"to satisfy RespectsToken({_token})";
+    }
+}
+
+public static partial class ValueTypeDefaultParameterAssertionExtensions
+{
+    /// <summary>
+    /// Generated extension method for RespectsToken
+    /// </summary>
+    public static Int_RespectsToken_CancellationToken_Assertion RespectsToken(this IAssertionSource<int> source, System.Threading.CancellationToken token = default, [CallerArgumentExpression(nameof(token))] string? tokenExpression = null)
+    {
+        source.Context.ExpressionBuilder.Append($".RespectsToken({tokenExpression})");
+        return new Int_RespectsToken_CancellationToken_Assertion(source.Context, token);
+    }
+
+}
+
+]