TRLS011 — Maybe is double-wrapped

• Severity: Warning
• Category: Trellis

What it detects

Flags declared Maybe<Maybe<T>> in variables, properties, method return types, and parameters.

Why it matters

Double optionality is usually a modeling smell. Consumers now have to unwrap presence twice before they can use the value.

Warning

Nested Maybe often appears after using Map with a transformation that already returns Maybe<T>.

Bad example

using Trellis;

static class Example
{
    public static Maybe<Maybe<int>> Bad() =>
        Maybe.From(Maybe.From(42));
}

Good example

using Trellis;

static class Example
{
    public static Maybe<int> Good() =>
        Maybe.From(42);
}

Code fix available

No.

Configuration

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

dotnet_diagnostic.TRLS011.severity = none

#pragma warning disable TRLS011
// Intentional: documented exception or test-only pattern.
#pragma warning restore TRLS011

Tip

If the inner computation can fail with details, consider Result<T> instead. Otherwise return a single Maybe<T>.