BE-525: HashQL: Remove implicit type-widening from Integer operations, and make comparison size aware

[indietyp]

🌟 What is the purpose of this PR?

Integer arithmetic in the MIR interpreter previously silently promoted overflowing i128 operations to floating-point results via a Numeric enum. This was semantically incorrect: the language specifies arbitrary-precision integers, and silently widening to f64 loses precision and masks errors. This PR replaces that silent promotion with explicit overflow detection, surfacing a user-facing IntegerOverflow runtime error when addition, subtraction, or negation exceeds the 128-bit range supported by the interpreter.

As a side effect, the Int type's equality, ordering, and hashing semantics are corrected so that booleans (1-bit integers) are treated as a distinct type from integers (128-bit), rather than comparing equal to numeric integers with the same value. This restores type-level correctness for Bool vs Int comparisons throughout the value layer.

🔍 What does this change?

• Adds a RuntimeError::IntegerOverflow variant with an operation field, and a corresponding integer_overflow diagnostic emitted under the RuntimeLimit category with a note that the interpreter supports up to 128-bit integers.
• Replaces the Neg, Add<Int>, and Sub<Int> operator impls on Int (which returned Numeric and silently promoted to f64 on overflow) with checked_neg, checked_add, and checked_sub methods that return Option<Int>.
• Removes the Numeric enum entirely, along with the From<Numeric> for Value conversion and all associated forwarding impls.
• Updates the binary and unary operation dispatch in the interpreter runtime to use the new checked methods and return RuntimeError::IntegerOverflow on None.
• Fixes Int's PartialEq, Ord, and Hash implementations to include the size field, so that Int::from(true) (1-bit) and Int::from(1_i32) (128-bit) are no longer considered equal.
• Fixes PartialEq<Int> for Num, PartialOrd<Int> for Num, and their reverses to return false/None when the Int is a boolean, since booleans are not a subtype of Number.
• Updates Value::Ord to guard the cross-type Integer/Number ordering arms with !this.is_bool() / !other.is_bool().
• Updates InstSimplifyVisitor::eval_un_op to return Option<Int> and skip constant folding for negation of i128::MIN.
• Adds interpreter tests for addition, subtraction, and negation overflow, and an inst_simplify test confirming that neg(i128::MIN) is not folded.
• Updates all unit tests in int.rs and mod.rs to reflect the corrected bool/int distinction.

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

This PR:

• does not modify any publishable blocks or libraries, or modifications do not need publishing

📜 Does this require a change to the docs?

The changes in this PR:

• are internal and do not require a docs change

🕸️ Does this require a change to the Turbo Graph?

The changes in this PR:

• do not affect the execution graph

🛡 What tests cover this?

• New interpreter tests: integer_add_overflow, integer_sub_overflow, integer_neg_overflow — each confirms a RuntimeLimit diagnostic is produced.
• New inst_simplify test: const_fold_neg_overflow — confirms that negation of i128::MIN is left unfolded.
• Updated unit tests in Int and Value covering corrected equality, ordering, hashing, and cross-type Num/Int comparisons.

❓ How to test this?

1. Run cargo test -p hashql-mir and confirm all tests pass.
2. Verify that the new snapshot const_fold_neg_overflow.snap matches the expected unfold output.
3. Confirm that expressions producing integer overflow at runtime emit a diagnostic with category RuntimeLimit and a message referencing the 128-bit limit.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
hash	Ready	Preview, Comment	May 8, 2026 8:46am
petrinaut	Ready	Preview	May 8, 2026 8:46am

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
hashdotdesign-tokens	Ignored	Preview	May 8, 2026 8:46am

[cursor]

PR Summary

Medium Risk
Changes core interpreter numeric semantics: integer add/sub/neg now error on i128 overflow instead of silently widening, and Bool vs Int equality/ordering/hashing is no longer value-only. This can alter runtime results and constant-folding output for existing programs relying on the old behavior.

Overview
Prevents silent type-widening from integer arithmetic by introducing a user-facing RuntimeError::IntegerOverflow diagnostic and making +, -, and unary neg on Int use checked operations that fail when results exceed the interpreter’s i128 range.

Updates Int, Num, and Value comparison/ordering/hashing semantics to be size-aware, treating 1-bit booleans as distinct from 128-bit integers (and disallowing bool↔number equality/ordering), and adjusts constant-folding (inst_simplify) to use these semantics and to skip folding negation overflow. Adds targeted runtime and pass tests/snapshots for overflow and bool-vs-int constant folding.

^{Reviewed by Cursor Bugbot for commit 1d64eff. Bugbot is set up for automated code reviews on this repo. Configure here.}

[indietyp]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• BE-513: HashQL: Rework dynamic aggregate size estimation #8697
• BE-512: HashQL: Allow cross-backend transitions for SwitchInt terminators #8696
• BE-524: HashQL: Remove island schedule module #8694
• BE-525: HashQL: Remove implicit type-widening from Integer operations, and make comparison size aware #8693 👈 (View in Graphite)
• BE-515: HashQL: Remove OFFSET 0 materialization fence from generated query #8650
• BE-514: HashQL: implement iterative adjustment passes in placement solver #8635
• BE-500, BE-501: HashQL: Unify mixed parameter resolution in data dependency analysis #8607
• BE-494: HashQL: Loop-breaker selection for recursive inlining #8600
• BE-482: HashQL: Remove logical not from MIR and fix postgres boolean lowering #8595
• BE-474: HashQL: Take into account terminator target eligibility in execution backend placement #8587
• BE-455: HashQL: Introduce evaluation orchestrator #8586
• BE-523: HashQL: Suspendable interpreter with structured values and input system #8675
• BE-522: HashQL: Expand stdlib type system with temporal types #8674
• BE-306: HashQL: PostgreSQL translation #8526
• BE-457: HashQL: MIR execution pipeline extensions for postgres compilation #8525
• BE-456: HashQL: Entity type model enrichment and graph store query extensions #8524
• BE-429: HashQL: Add island dependency graph with data requirement resolution #8501
• BE-428: HashQL: Simplify traversal tracking to path recording #8498
• BE-434: HashQL: Refactor entity storage path resolution with centralized schema mapping #8496
• BE-427: Add hashql-macros crate with procedural macros for ID types and symbols #8495
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[augmentcode]

🤖 Augment PR Summary

Summary: This PR fixes HashQL MIR interpreter integer semantics by removing implicit type-widening on overflow and making comparisons size-aware.

Changes:

• Adds RuntimeError::IntegerOverflow plus a new RuntimeLimit diagnostic for i128-range overflows.
• Updates runtime dispatch for Add/Sub/Neg on Int to use checked arithmetic and surface overflow as an explicit runtime error.
• Removes the Numeric enum and associated conversion plumbing that previously promoted overflowing Int operations into f64.
• Makes Int equality/ordering/hashing include the size field so Bool (1-bit) and Int (128-bit) are distinct at the value layer.
• Adjusts Num↔Int cross-type comparison to treat booleans as neither equal nor orderable with Num.
• Updates Value::Ord to only apply numeric ordering between Integer/Number for non-bool integers.
• Updates constant folding to avoid folding neg(i128::MIN) and adds interpreter + inst_simplify regression tests/snapshots for overflow cases.

_{🤖 Was this summary useful? React with 👍 or 👎}

[augmentcode]

Review completed. 1 suggestion posted.

Comment augment review to trigger a new review at any time.

[codecov]

Codecov Report

❌ Patch coverage is 97.42268% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.24%. Comparing base (58bba8c) to head (b87ca3d).

Files with missing lines	Patch %	Lines
libs/@local/hashql/mir/src/interpret/value/mod.rs	83.33%	1 Missing and 2 partials ⚠️
libs/@local/hashql/mir/src/interpret/error.rs	90.90%	1 Missing ⚠️
...hashql/mir/src/pass/transform/inst_simplify/mod.rs	87.50%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@                                            Coverage Diff                                             @@
##           bm/be-515-hashql-remove-offset-0-materialization-fence-from-generated    #8693       +/-   ##
==========================================================================================================
+ Coverage                                                                  53.92%   66.24%   +12.32%     
==========================================================================================================
  Files                                                                        778      934      +156     
  Lines                                                                      57232    84770    +27538     
  Branches                                                                    3839     4465      +626     
==========================================================================================================
+ Hits                                                                       30863    56160    +25297     
- Misses                                                                     26041    28062     +2021     
- Partials                                                                     328      548      +220     

Flag	Coverage Δ
apps.hash-ai-worker-ts	1.41% <ø> (ø)
apps.hash-api	0.00% <ø> (ø)
local.hash-backend-utils	0.00% <ø> (ø)
local.hash-graph-sdk	9.63% <ø> (ø)
local.hash-isomorphic-utils	0.00% <ø> (ø)
rust.hash-graph-api	2.52% <ø> (ø)
rust.hashql-compiletest	28.26% <ø> (ø)
rust.hashql-eval	79.70% <ø> (ø)
rust.hashql-mir	91.86% <97.42%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[codspeed-hq]

Merging this PR will not alter performance

✅ 24 untouched benchmarks
⏩ 56 skipped benchmarks¹

---

_{Comparing bm/be-525-hashql-remove-implicit-type-widening-into-num-for-int (b87ca3d) with bm/be-515-hashql-remove-offset-0-materialization-fence-from-generated (9db238d)²}

Footnotes

1. 56 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on bm/be-515-hashql-remove-offset-0-materialization-fence-from-generated (58bba8c) during the generation of this report, so 161d40f was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 07de63c. Configure here.}