[cknitt]

Primitive_option.some and valFromOption created a new {BS_PRIVATE_NESTED_SOME_NONE: depth} object on every call. This had two effects:

• Wrapping or unwrapping a nested None allocated each time. Generic code such as Option.map over an option<option<_>> runs through these functions.
• Two equal values were different objects: Some(None) === Some(None) was false, while Some(1) === Some(1) is true.

Now each depth has one frozen object, created on first use and returned by both functions:

let wrap = x => Some(x)
let none: option<int> = None
wrap(none) === wrap(none) // before: false, after: true

Generated code doesn't change: it calls the same two functions. Values are still recognised by the BS_PRIVATE_NESTED_SOME_NONE property, so two copies of the runtime, e.g. in two bundles, still work with each other's values. Only === between their objects stays false, as before. The objects are frozen because they are now shared, so a write through Obj.magic would otherwise affect every nested None of that depth.

New test option_nested_marker_test.res: identity at each depth, unwrapping to the marker one level down, frozen markers, and unchanged matching and equality.

🤖 Generated with Claude Code

https://claude.ai/code/session_015yE4gCmTmJKVecrVt1PU8C

[github-actions]

Changelog

💅 Polish

• Reuse one object per depth for nested None (Some(None), Some(Some(None)), …), so creating one no longer allocates and Some(None) === Some(None) holds.

Semantic Diff

1 commit · Full page

Reuse one frozen object per depth for a nested None

_{fbb13e4 · cknitt + Claude · Oct 24, 2026, 17:15 UTC}

Primitive_option.some and valFromOption created a new {BS_PRIVATE_NESTED_SOME_NONE: depth} object on every call. That allocates each time a nested None is wrapped or unwrapped, and makes two equal values different objects: Some(None) === Some(None) was false while Some(1) === Some(1) is true. Each depth now has one frozen object, created on first use.

Representation modified (nested None)

representation

 None             ↦ undefined
-Some(None)       ↦ a new {BS_PRIVATE_NESTED_SOME_NONE: 0} per call
-Some(Some(None)) ↦ a new {BS_PRIVATE_NESTED_SOME_NONE: 1} per call
-note: Some(None) === Some(None) is false
+Some(None)       ↦ the shared frozen {BS_PRIVATE_NESTED_SOME_NONE: 0}
+Some(Some(None)) ↦ the shared frozen {BS_PRIVATE_NESTED_SOME_NONE: 1}
+note: Some(None) === Some(None) is true

JS modified (Primitive_option.some)

js

+let markers = [];
+
+function marker(depth) {
+  let m = markers[depth];
+  if (m !== undefined) {
+    return m;
+  }
+  let m$1 = Object.freeze({
+    BS_PRIVATE_NESTED_SOME_NONE: depth
+  });
+  markers[depth] = m$1;
+  return m$1;
+}
+
 function some(x) {
   if (x === undefined) {
-    return {
-      BS_PRIVATE_NESTED_SOME_NONE: 0
-    };
+    return marker(0);
   } else if (x !== null && x.BS_PRIVATE_NESTED_SOME_NONE !== undefined) {
-    return {
-      BS_PRIVATE_NESTED_SOME_NONE: x.BS_PRIVATE_NESTED_SOME_NONE + 1 | 0
-    };
+    return marker(x.BS_PRIVATE_NESTED_SOME_NONE + 1 | 0);
   } else {
     return x;
   }
 }

Review

• Does this work with two copies of the runtime, e.g. in two bundles? Yes: a value is recognised by its property, not by identity, so each copy's objects work with the other copy; only === between them stays false, as before.
• Why freeze? The objects are now shared, so a write through Obj.magic would change every nested None of that depth.

[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 2026-10-24T17:22:27.478956Z	fbb13e4	Manual request

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Can't wait for the next one!

Reviewed commit: fbb13e432d

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.31%. Comparing base (d8db3c6) to head (fbb13e4).
⚠️ Report is 8 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9025      +/-   ##
==========================================
+ Coverage   81.29%   81.31%   +0.02%     
==========================================
  Files         456      456              
  Lines       63836    64006     +170     
==========================================
+ Hits        51893    52047     +154     
- Misses      11943    11959      +16     

see 38 files with indirect coverage changes

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