Moq not verifying Expressions as expected

[oisjack]

In reference to this question I asked on Stack Overflow, We're attempting to verify that a specific LINQ query was ran against a mock, but it fails no matter what we do. If I abridge the code being tested to the following:

public async Task<Activity> Get(long ID, Recruiter User, bool IsArchived = false)
{
    IAppQuery<Activity> result = collection.Where(x => x.ID == ID);

    return await result.FirstOrDefault();
}

And run the following test:

ActivitiesMock.Setup(x => x.Where(It.IsAny<Expression<Func<Activity, bool>>>())).Returns(queryMock.Object);
queryMock.Setup(x => x.FirstOrDefault()).ReturnsAsync(new Activity());

Activity result = await repo.Get(ID, User);

Assert.IsNotNull(result);

ActivitiesMock.Verify(x => x.Where(y => y.ID == ID));

The Assert.IsNotNull passes but the ActivitiesMock.Verify doesn't with the following error:

Test method Example.Tests.Backend.Repositories.ActivityRepositoryTests.GetDoesThings threw exception:
Moq.MockException:
Expected invocation on the mock at least once, but was never performed: x => x.Where(y => y.ID == .ID)

Configured setups:
x => x.Where(It.IsAny<Expression`1>()), Times.Once

Performed invocations:
IAppCollection`2.Where(x => (x.ID == value(Example.Backend.Repositories.ActivityRepository+<>c__DisplayClass2_0).ID))

Are we setting up a test incorrectly, are we expecting Moq to handle something it can't, or is this a bug in Moq?

[oisjack]

Looks like it's because of the DisplayClass. Unless there's a recommendation on how to get them to compare, we're going with storing the Expression as part of the Returns statement then compiling and invoking the predicate against things that should and shouldn't match and asserting it the result is true or false.