Implement variance checks for recursive protocols.

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
compilers

Research direction

Start by reading issue #3132 and locating the existing checks and tests for declared versus inferred variance in non-recursive protocols. Trace how mutually recursive protocols are analyzed as a group. Done means recursive protocol sets validate variance consistently, with tests covering interactions between protocols.

Written by the indexing model from the issue text.

Description

feature priority-1-normal topic-protocols topic-recursive-types

Currently, only non-recursive protocols are well tested w.r.t. declared vs inferred variance. It looks like a set of mutually recursive protocols should be checked as a unit, since the variance in one protocol can affect variance in another protocol.

This is a follow up for #3132

Dominant language
Python
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Avg merge
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Merged PRs (30d)
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