TRLS007: Use Create instead of TryCreate().Value

Cause

Using .Value immediately after calling TryCreate(), which provides unclear intent and poor error messages.

Rule Description

When creating value objects, there are two factory methods:

TryCreate() - Returns Result<T> for scenarios where failure is expected and should be handled
Create() - Throws an exception for scenarios where the value is known to be valid

Using TryCreate().Value combines the worst of both worlds:

❌ Throws an exception like Create() (not handling the Result)
❌ But with a generic "Result is in failure state" message instead of the specific validation error

How to Fix Violations

Use Create() when you expect the value to be valid

// ❌ Bad - Unclear intent, poor error message
var email = EmailAddress.TryCreate("test@example.com").Value;
// Throws: "Result is in failure state" (generic message)

// ✅ Good - Clear intent, detailed error message
var email = EmailAddress.Create("test@example.com");
// Throws: "Failed to create EmailAddress: Email address is not valid." (specific message)

Or handle the Result properly

// ✅ Good - Proper error handling
var result = EmailAddress.TryCreate(userInput);
if (result.IsFailure)
    return BadRequest(result.Error);

var email = result.Value;

When to Use Each Pattern

Use `Create()` when:

✅ Value comes from constants or configuration
✅ Value is already validated
✅ Failure would be a programming error
✅ In test code with known-valid values

// ✅ Good - constant value
var defaultCurrency = CurrencyCode.Create("USD");

// ✅ Good - already validated
var total = Money.Create(item1.Amount + item2.Amount, "USD");

// ✅ Good - test data
[Fact]
public void Should_CreateOrder()
{
    var customer = Customer.Create("test@example.com", "John");
    // ...
}

Use `TryCreate()` when:

✅ Value comes from user input
✅ Value comes from external systems
✅ Failure is a expected business scenario
✅ You want to handle errors gracefully

// ✅ Good - user input
return EmailAddress.TryCreate(dto.Email)
    .Bind(email => Customer.Create(email, dto.Name))
    .Map(customer => customer.ToDto())
    .Match(
        onSuccess: dto => Ok(dto),
        onFailure: error => BadRequest(error));

Code Fix

This diagnostic offers an automatic code fix that replaces TryCreate().Value with Create():

Example Code Fix Transformation

Before:

var name = Name.TryCreate("John").Value;
var email = EmailAddress.TryCreate("test@example.com").Value;
var customer = Customer.Create(name, email);

After (automatic):

var name = Name.Create("John");
var email = EmailAddress.Create("test@example.com");
var customer = Customer.Create(name, email);

Error Message Comparison

Using TryCreate().Value (bad):

Unhandled exception: System.InvalidOperationException: Result is in failure state.
   at Trellis.Result`1.get_Value()
   at MyApp.CreateCustomer()

Using Create() (good):

Unhandled exception: System.InvalidOperationException: Failed to create EmailAddress: Email address is not valid.
   at EmailAddress.Create()
   at MyApp.CreateCustomer()

The Create() version includes the actual validation error details!

TRLS003 - Unsafe access to Result.Value

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