Equivalence between KeyImpl and TypedKeyImpl is not symmetric

Expected behavior

Object#equals's contract requires:

It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.

Observed/Actual behavior

Equivalence between TypedKeyImpl and KeyImpl is not symmetric

Steps/models to reproduce

Key key = Key.key("minecraft:stone");
TypedKey<ItemType> typedKey = TypedKey.create(RegistryKey.ITEM, key);
System.out.println(key.equals(typedKey)); // true
System.out.println(typedKey.equals(key)); // false

Plugin and Datapack List

None

Paper version

This server is running Paper version 1.21.11-126-main@3f5728e (2026-02-28T11:49:07Z) (Implementing API version 1.21.11-R0.1-SNAPSHOT)

Other

In my opinion TypedKey shouldn't extend Key. But since it is too late to change this now, I think the problem could be solved by:

1. In TypedKeyImpl, override equals and check if the other object is also a TypedKey. If so, additionally compare registry key. Otherwise, only compare namespace and value.
2. In TypedKeyImpl, override hashCode and replace its implementation with that of KeyImpl (from adventure), such that the registry key has no influence on the hash code and equal keys have equal hash codes.

Start with the KeyImpl and TypedKeyImpl equality and hashCode implementations, then reproduce the asymmetric results from the issue's Java example. Done means the equality contract and hash-code relationship described in the issue are satisfied; pull request #14152 is already open for this issue.