Deprecate Comparable

text/1113-deprecate-comparable.md

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+---
+stage: accepted
+start-date: 2025-06-13T00:00:00.000Z
+release-date:
+release-versions:
+teams: # delete teams that aren't relevant
+  - cli
+  - data
+  - framework
+  - learning
+  - steering
+  - typescript
+prs:
+  accepted: https://github.com/emberjs/rfcs/pull/1113
+project-link:
+---
+
+<!---
+Directions for above:
+
+stage: Leave as is
+start-date: Fill in with today's date, 2032-12-01T00:00:00.000Z
+release-date: Leave as is
+release-versions: Leave as is
+teams: Include only the [team(s)](README.md#relevant-teams) for which this RFC applies
+prs:
+  accepted: Fill this in with the URL for the Proposal RFC PR
+project-link: Leave as is
+-->
+
+# Deprecating the `Comparable` Mixin
+
+## Summary
+
+Deprecate the `Comparable` Mixin.
+
+## Motivation
+
+For a while now, Ember has not recommended the use of Mixins. In order to fully
+deprecate Mixins, we need to deprecate all existing Mixins of which `Comparable` is one.
+
+## Transition Path
+
+None. This will be removed without replacement.
+
+## Exploration
+
+To validate this deprecation, I've tried removing the `Comparable` Mixin from Ember.js in this PR:
+https://github.com/emberjs/ember.js/pull/20924
+
+## How We Teach This
+
+We should remove all references from the guides.
+
+## Drawbacks
+
+Some users probably rely on this functionality. However, it's almost certainly
+something that we don't need to keep in Ember itself.
+
+## Alternatives
+
+* Convert `Comparable` to a class decorator-style mixin.
+
+## Unresolved questions
+
+None