TRLS009 — Incorrect async Result usage

• Severity: Warning
• Category: Trellis

What it detects

Flags blocking access on Task<Result<T>> and ValueTask<Result<T>>: .Result, .Wait(), and .GetAwaiter().GetResult().

Why it matters

Blocking async Result pipelines can deadlock, hide cancellation behavior, and makes failure handling harder to reason about.

Warning

This rule covers both Task and ValueTask. Replacing .Result with .GetAwaiter().GetResult() does not avoid the diagnostic.

Bad example

using System.Threading.Tasks;
using Trellis;

static class Example
{
    public static Result<int> Bad()
    {
        var pending = GetCountAsync();
        return pending.GetAwaiter().GetResult();
    }

    static ValueTask<Result<int>> GetCountAsync() =>
        new(Result.Success(42));
}

Good example

using System.Threading.Tasks;
using Trellis;

static class Example
{
    public static async ValueTask<Result<int>> Good() =>
        await GetCountAsync();

    static ValueTask<Result<int>> GetCountAsync() =>
        new(Result.Success(42));
}

Code fix available

No.

Configuration

Use standard Roslyn configuration if you need to suppress this rule in a specific scope.

dotnet_diagnostic.TRLS009.severity = none

#pragma warning disable TRLS009
// Intentional: documented exception or test-only pattern.
#pragma warning restore TRLS009

Tip

Once a method touches Task<Result<T>> or ValueTask<Result<T>>, keep the method async and await the result all the way through.