Partially covered await foreach statement

[meggima]

Hello

In the following code the await foreach as well as the for and the yield statements are marked as partially covered due to the hidden async/await logic of the compiler. Can this be reported as covered by coverlet?

Reproduction class:

public class AwaitForeachReproduction
{
    public async Task<int> Execute()
    {
        int sum = 0;

        await foreach (int result in AsyncEnumerable())
        {
            sum += result;
        }

        return sum;
    }

    private async IAsyncEnumerable<int> AsyncEnumerable()
    {
        for(int i = 0; i < 100; i++)
        {
            await Task.Delay(10);
            yield return i;
        }
    }
}

Test Case for it:

public class AwaitForeachReproductionFixture
{
    [Fact]
    public async Task Execute_ShouldWork()
    {
        // Arrange
        var sut = new AwaitForeachReproduction();

        // Act
        int result = await sut.Execute();

        // Assert
        Assert.Equal(4950, result);
    }
}

Reported coverage:

Coverlet version: 3.0.3

[meggima]

You can find the full reproduction code (and also for some other cases) in this repository: https://github.com/meggima/coverlet-reproductions

[MarcoRossignoli]

assigned to @alexthornton1

[MarcoRossignoli]

Closed in #1107

[ipetrushevskiy]

If you change the AsyncEnumerable method in the original example like that (by adding attribute for cancellation Token support - code below), it will be still partially covered.

private async IAsyncEnumerable<int> AsyncEnumerable([EnumeratorCancellation] CancellationToken cancellationToken)
{
    for(int i = 0; i < 100; i++)
    {
        await Task.Delay(10, cancellationToken);
        yield return i;
    }
}