ExcludingMissingMembers overwrites WithMapping

[jnyrup]

Description

Calling ExcludingMissingMembers/ThrowingOnMissingMembers calls ClearMatchingRules() and potentially removes an instance of MappedMemberMatchingRule.

Complete minimal example reproducing the issue

[Fact]
public void Exclusion_of_missing_members_works_with_mapping()
{
    // Arrange
    var subject = new { Property1 = 1 };

    var expectation = new { Property2 = 2, Ignore = 3 };

    // Act / Assert
    subject.Should()
        .NotBeEquivalentTo(expectation, opt => opt
            .WithMapping("Property2", "Property1")
            .ExcludingMissingMembers()
        );
}

[Fact]
public void Mapping_works_with_exclusion_of_missing_members()
{
    // Arrange
    var subject = new { Property1 = 1 };

    var expectation = new { Property2 = 2, Ignore = 3 };

    // Act / Assert
    subject.Should()
        .NotBeEquivalentTo(expectation, opt => opt
            .ExcludingMissingMembers()
            .WithMapping("Property2", "Property1")
        );
}

Expected behavior:

Both should pass

Actual behavior:

Exclusion_of_missing_members_works_with_mapping fails with

Expected subject not to be equivalent to { Property2 = 2, Ignore = 3 }, but they are.

Versions

• Which version of Fluent Assertions are you using?
  • develop / 418a405