Nullable Properties

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Properties declared with a nullable reference type (string?, MyClass?) receive null-safe comparison in the generated Equals method.

Example

[ValueObject]
public partial class Contact
{
    public string Name { get; }
    public string? Email { get; }    // nullable
    public string? Phone { get; }    // nullable

    public Contact(string name, string? email = null, string? phone = null)
    {
        Name = name; Email = email; Phone = phone;
    }
}

Generated equality:

public bool Equals(Contact? other) =>
    other is not null &&
    Name == other.Name &&
    (other.Email is null ? Email is null : Email == other.Email) &&
    (other.Phone is null ? Phone is null : Phone == other.Phone);

The null-safe pattern avoids a NullReferenceException without any extra heap allocation.

Behaviour

var c1 = new Contact("Alice", null, "555-0100");
var c2 = new Contact("Alice", null, "555-0100");
var c3 = new Contact("Alice", "[email protected]", "555-0100");

c1 == c2  // true  — both Email are null
c1 == c3  // false — Email differs (null vs non-null)

Non-nullable properties

For non-nullable properties (string, MyClass), a simple == comparison is generated. The compiler's null-safety analysis ensures these are never null at runtime when nullable reference types are enabled.

// Non-nullable → simple comparison
Name == other.Name

// Nullable → null-safe comparison
(other.Email is null ? Email is null : Email == other.Email)