Jonas Nyrup

> Then what is the point of this API. As I understand it, the point of this API is _given a correct_ implementation of `IParseable` (implemented by myself or from...

I assume you're using `WithTracing` somewhere, since `StringBuilderTraceWriter` otherwise shouldn't be used at all. Where are you calling `WithTracing` from?

This reproduces the exception ```cs using FluentAssertions; using FluentAssertions.Execution; AssertionOptions.AssertEquivalencyUsing(e => e.WithTracing()); Parallel.For(1, 10_000, (_, _) => { try { new { A = "a" }.Should().BeEquivalentTo(new { A = "b"...

Setting `WithTracing` globally should not be causing issues, so this is a bug in Fluent Assertions. The two workarounds I can currently think of are: * setting `WithTracing()` per test...

With the current `WithTracing(ITraceWriter writer)` method, this implementation of `ITraceWriter` seems to work better. It might not be bullet-proof, as it relies on `ITraceWriter.ToString()` always to be called to clear...

To list the use cases as I see them: When attached from within a test we don't need pools and thread-safety. This is how the current API was designed for....

> @jnyrup you agree? I agree, go ahead.

If the method signature `MatchRegex` is changed to `AndWhichConstraint` and #2597 gets merged, it could even be written as ```cs [Test] public void SomethingReturnsValidCode() { var resultOfSystemUnderTest = "abc123XY"; resultOfSystemUnderTest.Should().MatchRegex(new...

I agree about not going down the `TwoDimensionalArrayAssertions` path. Since `Array.GetValue()` has overloads for up to three indices before deferring to `params int[] indices` or `params long[] indices`, Let's as...

This is detected by https://github.com/fluentassertions/fluentassertions.analyzers  I would suggest using either of these ```cs m.Property.Should().Be(1); ``` ```cs (m?.Property).Should().Be(1); ``` ```cs m.Should().NotBeNull(); m.Property.Should().Be(1); ```