[Bug]: Compilation error on set types that implement both IReadonlySet and ISet

[guythetechie]

Description

I cannot write assertions directly on System.Collections.Immutable.ImmutableHashSet<T>, which implements both IReadonlySet<T> and ISet<T>. Workaround is to cast it as one of those types first.

This was working in version 1.7.20.

Expected Behavior

I expected the code to compile.

Actual Behavior

It gives this error:

The call is ambiguous between the following methods or properties: 'TUnit.Assertions.Assert.That<TItem>(System.Collections.Generic.IReadOnlySet<TItem>?, string?)' and 'TUnit.Assertions.Assert.That<TItem>(System.Collections.Generic.ISet<TItem>?, string?)'

Steps to Reproduce

Minimal reproduction code:

[Test]
public async Task Set_is_empty()
{
    var set = ImmutableHashSet<int>.Empty;
    await Assert.That(set).IsEmpty();
}

TUnit Version

1.11.8

.NET Version

.NET 10

Operating System

Windows

IDE / Test Runner

dotnet CLI (dotnet test / dotnet run)

Error Output / Stack Trace

Additional Context

No response

IDE-Specific Issue?

• I've confirmed this issue occurs when running via dotnet test or dotnet run, not just in my IDE

[guythetechie]

@thomhurst - thanks! You should publish a blog post about your workflow; the speed at which you resolve issues is remarkable.