Is this a bug when comparing a nullable type with its underlying type using FluentAssertions?

I was writing some unit tests for a utility library when I came across a test I would expect to fail that actually passed. The issue is related to comparing two `float` variables, versus comparing one `float?` and one `float` variable. I'm using the latest versions of both NUnit (2.6.0.12051) and FluentAssertions (1.7.1), and below is a small code snipped illustrating the issue: ``` using FluentAssertions; using FluentAssertions.Assertions; using NUnit.Framework; namespace CommonUtilities.UnitTests { [TestFixture] public class FluentAssertionsFloatAssertionTest { [Test] public void TestFloatEquality() { float expected = 3.14f; float notExpected = 1.0f; float actual = 3.14f; actual.Should().BeApproximately(expected, 0.1f); actual.Should().BeApproximately(notExpected, 0.1f); // A: Correctly fails (Expected value 3,14 to approximate 1 +/- 0,1, but it differed by 2,14.) actual.Should().BeInRange(expected, expected); actual.Should().BeInRange(notExpected, notExpected); // B: Correctly fails (Expected value 3,14 to be between 1 and 1, but it was not.) } [Test] public void TestNullableFloatEquality() { float expected = 3.14f; float notExpected = 1.0f; float? actual = 3.14f; actual.Should().BeApproximately(expected, 0.1f); actual.Should().BeApproximately(notExpected, 0.1f); // C: Passes (I expected it to fail!) actual.Should().BeInRange(expected, expected); actual.Should().BeInRange(notExpected, notExpected); // D: Correctly fails (Expected value 3,14 to be between 1 and 1, but it was not.) } } } ``` As you can see from my comments, in `TestFloatEquality()` both A and B fails correctly (just comment out the first failing test to get to the second one). In `TestNullableFloatEquality()` however, D passes but C fails. I would have expected C to fail here as well. And just to have mentioned it, if I add assertions using NUnit: ``` Assert.AreEqual(expected, actual); // Passes Assert.AreEqual(notExpected, actual); // Fails (Expected: 1.0f But was: 3.1400001f) ``` those pass and fail as expected. So, to the question: Is this a bug in FluentAssertions, or am I missing something with respect to nullable comparison?