TRLS001 — Result return value is not handled

• Severity: Warning
• Category: Trellis

What it detects

Flags Result<T> values that are produced and immediately discarded. That includes bare expression statements like CreateUser(...) and discarded await expressions whose awaited type is Task<Result<T>> or ValueTask<Result<T>>.

Why it matters

A Result<T> exists to carry success or failure. If you drop it on the floor, you also drop the error information and break the pipeline.

Warning

Ignoring a Result<T> is easy to do in async code. await SomeCallAsync(); still counts as discarded if the awaited value is a Result<T>.

Bad example

using System.Threading.Tasks;
using Trellis;

static class Example
{
    public static async Task SaveAsync(string email)
    {
        await CreateCustomerAsync(email);
    }

    static ValueTask<Result<int>> CreateCustomerAsync(string email) =>
        new(Result.Success(email.Length));
}

Good example

using System.Threading.Tasks;
using Trellis;

static class Example
{
    public static async Task<Result<int>> SaveAsync(string email)
    {
        var result = await CreateCustomerAsync(email);
        return result;
    }

    static ValueTask<Result<int>> CreateCustomerAsync(string email) =>
        new(Result.Success(email.Length));
}

Code fix available

No.

Configuration

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

dotnet_diagnostic.TRLS001.severity = none

#pragma warning disable TRLS001
// Intentional: documented exception or test-only pattern.
#pragma warning restore TRLS001

Tip

If you are at a boundary, return the Result, convert it with Match or MatchError, or explicitly assign it so the next step can handle success and failure.