[cknitt]

tests/syntax_tests/data/idempotency held about 109k lines of old community projects converted from Reason (bs-css, reason-react, pupilfirst, …). Only the roundtrip run of scripts/test_syntax.sh used it, checking that printing twice gives the same output. Every syntax deprecation or removal had to rewrite it, and its history shows no printer bug it caught.

I compared bisect_ppx line coverage of compiler/syntax for the regular syntax tests against a roundtrip of the corpus. The corpus covered 25 lines nothing else did. Each one traces to a construct that now has a minimal snippet in an existing printer fixture:

• module type path with a lowercase last segment (module Events: RGLEvents.t)
• %raw string with backslash escapes
• // comment between a JSX prop name and its value
• type-constrained switch scrutinee; switch cases with array/tuple/object/record bodies
• array set whose value is a binary expression
• ternary in function position (x->(c ? f : g)(~a))
• int/float JSX prop values
• deeply nested callbacks (custom-layout threshold) and a callback-first call containing a nested callback with an if (switch …) condition
• single char literal argument
• poly variant type with a type, not a tag, in first position
• braced block statement followed by a line comment
• non-ASCII template literal inside a JSX child (exercises the scanner's unknown-character path during lookahead)

With these fixtures added, rerunning the comparison finds no line that only the corpus covers.

🤖 Generated with Claude Code

https://claude.ai/code/session_01UoDHhLCpoQeKvfN6VbVcHv

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Changelog

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Semantic Diff

1 commit · Full page

Remove the converted Reason project corpus from the syntax tests

_{3448ada · cknitt + Claude · Oct 24, 2026, 07:34 UTC}

Constructs only the corpus covered are now printer fixtures.

[cknitt]

@codex review

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-24T07:37:41.661256Z	3448ada	Manual request

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Keep it up!

Reviewed commit: 3448ada827

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• Open a pull request for review
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• Comment "@codex review".

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.31%. Comparing base (a42a937) to head (3448ada).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9012      +/-   ##
==========================================
- Coverage   81.31%   81.31%   -0.01%     
==========================================
  Files         456      456              
  Lines       63979    63979              
==========================================
- Hits        52024    52022       -2     
- Misses      11955    11957       +2     

see 2 files with indirect coverage changes

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