fix(assertions): gate IsEqualTo<TValue, TOther> overload to net9+ (#5765)

TUnit.Assertions.Tests/Bugs/Issue5720Tests.cs

@@ -1,3 +1,5 @@
+// Gated to match ImplicitConversionEqualityExtensions.cs — see issue #5765.
+#if NET9_0_OR_GREATER
 namespace TUnit.Assertions.Tests.Bugs;
 
 /// <summary>
@@ -191,3 +193,5 @@ await Assert.That(assertionException.InnerException!.Message).StartsWith(
             $"No implicit conversion operator from '{typeof(UnrelatedType)}' to '{typeof(string)}' was found.");
     }
 }
+
+#endif

TUnit.Assertions.Tests/Bugs/Issue5765Tests.cs

@@ -0,0 +1,40 @@
+using System.Net;
+
+namespace TUnit.Assertions.Tests.Bugs;
+
+public class Issue5765Tests
+{
+    [Test]
+    public async Task IsEqualTo_SameType_Enum()
+    {
+        var status = HttpStatusCode.OK;
+
+        await Assert.That(status).IsEqualTo(HttpStatusCode.OK);
+    }
+
+    [Test]
+    public async Task IsEqualTo_SameType_Primitive()
+    {
+        var value = 42;
+
+        await Assert.That(value).IsEqualTo(42);
+    }
+
+    [Test]
+    public async Task IsEqualTo_SameType_Record()
+    {
+        var point = new Point(1, 2);
+
+        await Assert.That(point).IsEqualTo(new Point(1, 2));
+    }
+
+    [Test]
+    public async Task IsNotEqualTo_SameType_Enum()
+    {
+        var status = HttpStatusCode.OK;
+
+        await Assert.That(status).IsNotEqualTo(HttpStatusCode.NotFound);
+    }
+
+    private sealed record Point(int X, int Y);
+}

TUnit.Assertions/Extensions/ImplicitConversionEqualityExtensions.cs

@@ -1,3 +1,8 @@
+// Gated to .NET 9+ because these overloads rely on [OverloadResolutionPriority] to
+// lose to the source-generated single-generic IsEqualTo / IsNotEqualTo on same-type
+// calls, and that attribute is silently dropped on net8.0 / netstandard2.0 (Polyfill
+// does not supply it), causing CS0121. See issue #5765.
+#if NET9_0_OR_GREATER
 using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
@@ -146,3 +151,4 @@ internal static class ImplicitConversionCache
         return null;
     }
 }
+#endif

TUnit.PublicAPI/Tests.Assertions_Library_Has_No_API_Changes.DotNet8_0.verified.txt

@@ -3767,9 +3767,6 @@ namespace .Extensions
     {
         public static .<TValue> IsEqualTo<TValue>(this .<TValue> source, TValue? expected, [.("expected")] string? expectedExpression = null) { }
         public static .<TValue> IsEqualTo<TValue>(this .<TValue> source, TValue? expected, .<TValue> comparer, [.("expected")] string? expectedExpression = null, [.("comparer")] string? comparerExpression = null) { }
-        [.("Looks up implicit conversion operators via reflection. Trimming may remove user-d" +
-            "efined operators.")]
-        public static .<TOther> IsEqualTo<TValue, TOther>(this .<TValue> source, TOther? expected, [.("expected")] string? expectedExpression = null) { }
     }
     public static class EquatableAssertionExtensions
     {
@@ -4696,9 +4693,6 @@ namespace .Extensions
     public static class NotEqualsAssertionExtensions
     {
         public static .<TValue> IsNotEqualTo<TValue>(this .<TValue> source, TValue notExpected, .<TValue>? comparer = null, [.("notExpected")] string? notExpectedExpression = null, [.("comparer")] string? comparerExpression = null) { }
-        [.("Looks up implicit conversion operators via reflection. Trimming may remove user-d" +
-            "efined operators.")]
-        public static .<TOther> IsNotEqualTo<TValue, TOther>(this .<TValue> source, TOther? notExpected, [.("notExpected")] string? notExpectedExpression = null) { }
     }
     public static class NotEquivalentToAssertionExtensions
     {

TUnit.PublicAPI/Tests.Assertions_Library_Has_No_API_Changes.Net4_7.verified.txt

@@ -3360,7 +3360,6 @@ namespace .Extensions
     {
         public static .<TValue> IsEqualTo<TValue>(this .<TValue> source, TValue? expected, [.("expected")] string? expectedExpression = null) { }
         public static .<TValue> IsEqualTo<TValue>(this .<TValue> source, TValue? expected, .<TValue> comparer, [.("expected")] string? expectedExpression = null, [.("comparer")] string? comparerExpression = null) { }
-        public static .<TOther> IsEqualTo<TValue, TOther>(this .<TValue> source, TOther? expected, [.("expected")] string? expectedExpression = null) { }
     }
     public static class EquatableAssertionExtensions
     {
@@ -4189,7 +4188,6 @@ namespace .Extensions
     public static class NotEqualsAssertionExtensions
     {
         public static .<TValue> IsNotEqualTo<TValue>(this .<TValue> source, TValue notExpected, .<TValue>? comparer = null, [.("notExpected")] string? notExpectedExpression = null, [.("comparer")] string? comparerExpression = null) { }
-        public static .<TOther> IsNotEqualTo<TValue, TOther>(this .<TValue> source, TOther? notExpected, [.("notExpected")] string? notExpectedExpression = null) { }
     }
     public static class NotEquivalentToAssertionExtensions
     {