A hand-written Equals(TBase) on a value object is kept, and a collection of the base compares by it #196

Package

CodoMetis.TypeKit.Generators

Version

2.3.0, and every release that generates equality over a base record

How does it fail?

Silently. It compiles or answers, and does less than it appears to

What you ran

A value object over a base record declares an Equals for one of its base types:

public abstract record DeepBase;
public abstract record MiddleBase : DeepBase;

public sealed partial record Tag : MiddleBase, IValue<string>
{
    public bool Equals(DeepBase? other) => ReferenceEquals(this, other);
}

Tag.From("a") == Tag.From("a");                              // true
new HashSet<DeepBase> { Tag.From("a"), Tag.From("a") }.Count;  // 2
new HashSet<Tag> { Tag.From("a"), Tag.From("a") }.Count;       // 1

What you got

Measured on release/2.4.0 at 97c87c1, 2026-10-30. ValueObjectDeclaration.EqualityDeclaredByHand refuses Equals(TSelf), GetHashCode() and an explicit IEquatable<TSelf>.Equals, and reads no Equals(TBase). The hand-written one implements IEquatable<DeepBase> (re-listed through IReimplementedEquatable<DeepBase>), and ValueObjectContractAspect.IntroduceEquality skips its own new Equals(TBase) when the value object declares one, so a collection of the base compares by reference while the value object's equality is its wrapped value's.

What you expected

CMTK1011, as for a hand-written Equals(TSelf): a value object's equality is its wrapped value's. Reported from an outside review of #193.

Environment

.NET SDK 10.0.4xx, Metalama 2026.1; any consumer.