NonComparableStreamSort validates direct types

[carterkozak]

Before this PR

Previously NonComparableStreamSort only failed on types which
would cause a compilation error casting to Comparable. Now we
validate that the stream type is a subtype of Comparable.

After this PR

==COMMIT_MSG==
Improve NonComparableStreamSort to validate that stream types implement comparable, as opposed to validating that casting to comparable does not cause a compiler error.

This commit reduces the severity to WARNING because it's
possible that the check will flag code that happens to work
today, but we strongly recommend against sorting streams of
a type that is not directly comparable without a custom
comparator because it is likely to break later due to lack
of enforcement by the type system.
==COMMIT_MSG==

Possible downsides?

Possible this will cause friction if it flags new things. That friction is substantially lower than failures at runtime.

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Type

• Feature
• Improvement
• Fix
• Break
• Deprecation
• Manual task
• Migration

Description

Improve NonComparableStreamSort to validate that stream types implement comparable, as opposed to validating that casting to comparable does not cause a compiler error.

This commit reduces the severity to WARNING because it's
possible that the check will flag code that happens to work
today, but we strongly recommend against sorting streams of
a type that is not directly comparable without a custom
comparator because it is likely to break later due to lack
of enforcement by the type system.

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[stale]

This PR has been automatically marked as stale because it has not been touched in the last 14 days. If you'd like to keep it open, please leave a comment or add the 'long-lived' label, otherwise it'll be closed in 7 days.

[carterkozak]

not stale, just awaiting review