feat!: Follow pass scopes in composable passes by aborgna-q · Pull Request #1429 · Quantinuum/tket2

aborgna-q · 2026-03-02T13:57:45Z

Adds support for PassScopes in the pass definitions. See Quantinuum/hugr#2772.

~~Requires a hugr release with the PassScope definition and Quantinuum/hugr#2910.~~

~~Many of these also call other passes from hugr_passes. While we pass the scope config along, proper support requires Quantinuum/hugr#2836 and Quantinuum/hugr#2871.~~

This is a rust-only change, the python interface will follow up.

BREAKING CHANGE: Multiple unit-like pass structs must now be constructed using a ::default() call instead.
BREAKING CHANGE: QSystemPass is now a ComposablePass. Import the trait to call run.
BREAKING CHANGE: QSystemPass no longer implements Copy.
BREAKING CHANGE: Renamed tket_qsystem::extension::qsystem::lower_tket_op to lower_tket_ops.

hugrbot · 2026-03-02T14:12:11Z

This PR contains breaking changes to the public Rust API.

cargo-semver-checks summary

    Building tket v0.17.0 (current)
     Built [  42.793s] (current)
   Parsing tket v0.17.0 (current)
    Parsed [   0.083s] (current)
  Building tket v0.17.0 (baseline)
     Built [  41.164s] (baseline)
   Parsing tket v0.17.0 (baseline)
    Parsed [   0.078s] (baseline)
  Checking tket v0.17.0 -> v0.17.0 (assume minor change)
   Checked [   0.107s] 196 checks: 193 pass, 3 fail, 0 warn, 56 skip

--- failure derive_trait_impl_removed: built-in derived trait no longer implemented ---

Description:
A public type has stopped deriving one or more traits. This can break downstream code that depends on those types implementing those traits.
      ref: https://doc.rust-lang.org/reference/attributes/derive.html#derive
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.47.0/src/lints/derive_trait_impl_removed.ron

Failed in:
type NormalizeGuppy no longer derives Copy, in /home/runner/work/tket2/tket2/PR_BRANCH/tket/src/passes/guppy.rs:23
type NormalizeGuppy no longer derives Copy, in /home/runner/work/tket2/tket2/PR_BRANCH/tket/src/passes/guppy.rs:23

--- failure inherent_method_missing: pub method removed or renamed ---

Description:
A publicly-visible method or associated fn is no longer available under its prior name. It may have been renamed or removed entirely.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.47.0/src/lints/inherent_method_missing.ron

Failed in:
BorrowSquashPass::set_regions, previously in file /home/runner/work/tket2/tket2/BASELINE_BRANCH/tket/src/passes/borrow_squash.rs:35
BorrowSquashPass::set_regions, previously in file /home/runner/work/tket2/tket2/BASELINE_BRANCH/tket/src/passes/borrow_squash.rs:35

--- failure unit_struct_changed_kind: unit struct changed kind ---

Description:
A public unit struct has been changed to a normal (curly-braces) struct, which cannot be constructed using the same struct literal syntax.
      ref: https://github.com/rust-lang/cargo/pull/10871
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.47.0/src/lints/unit_struct_changed_kind.ron

Failed in:
struct ModifierResolverPass in /home/runner/work/tket2/tket2/PR_BRANCH/tket/src/modifier/pass.rs:13

   Summary semver requires new major version: 3 major and 0 minor checks failed
  Finished [  86.544s] tket
  Building tket-qsystem v0.23.0 (current)
     Built [  41.636s] (current)
   Parsing tket-qsystem v0.23.0 (current)
    Parsed [   0.027s] (current)
  Building tket-qsystem v0.23.0 (baseline)
     Built [  41.833s] (baseline)
   Parsing tket-qsystem v0.23.0 (baseline)
    Parsed [   0.027s] (baseline)
  Checking tket-qsystem v0.23.0 -> v0.23.0 (assume minor change)
   Checked [   0.053s] 196 checks: 193 pass, 3 fail, 0 warn, 56 skip

--- failure derive_trait_impl_removed: built-in derived trait no longer implemented ---

Description:
A public type has stopped deriving one or more traits. This can break downstream code that depends on those types implementing those traits.
      ref: https://doc.rust-lang.org/reference/attributes/derive.html#derive
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.47.0/src/lints/derive_trait_impl_removed.ron

Failed in:
type QSystemPass no longer derives Copy, in /home/runner/work/tket2/tket2/PR_BRANCH/tket-qsystem/src/lib.rs:39

--- failure function_parameter_count_changed: pub fn parameter count changed ---

Description:
A publicly-visible function now takes a different number of parameters.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#fn-change-arity
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.47.0/src/lints/function_parameter_count_changed.ron

Failed in:
tket_qsystem::extension::qsystem::check_lowered now takes 2 parameters instead of 1, in /home/runner/work/tket2/tket2/PR_BRANCH/tket-qsystem/src/extension/qsystem/lower.rs:283
tket_qsystem::extension::qsystem::lower_tk2_op now takes 2 parameters instead of 1, in /home/runner/work/tket2/tket2/PR_BRANCH/tket-qsystem/src/extension/qsystem/lower.rs:106

--- failure unit_struct_changed_kind: unit struct changed kind ---

Description:
A public unit struct has been changed to a normal (curly-braces) struct, which cannot be constructed using the same struct literal syntax.
      ref: https://github.com/rust-lang/cargo/pull/10871
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.47.0/src/lints/unit_struct_changed_kind.ron

Failed in:
struct LowerTketToQSystemPass in /home/runner/work/tket2/tket2/PR_BRANCH/tket-qsystem/src/extension/qsystem/lower.rs:322
struct ReplaceBoolPass in /home/runner/work/tket2/tket2/PR_BRANCH/tket-qsystem/src/replace_bools.rs:70
struct LowerDropsPass in /home/runner/work/tket2/tket2/PR_BRANCH/tket-qsystem/src/lower_drops.rs:15

   Summary semver requires new major version: 3 major and 0 minor checks failed
  Finished [  86.061s] tket-qsystem

codecov · 2026-03-02T14:12:29Z

Codecov Report

❌ Patch coverage is 68.13187% with 58 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.98%. Comparing base (f43a877) to head (f55c27f).
⚠️ Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
tket-qsystem/src/lib.rs	58.53%	26 Missing and 8 partials ⚠️
tket-qsystem/src/extension/qsystem/lower.rs	80.95%	3 Missing and 5 partials ⚠️
tket/src/passes/guppy.rs	62.50%	2 Missing and 4 partials ⚠️
tket/src/modifier/pass.rs	0.00%	5 Missing ⚠️
tket-qsystem/src/replace_bools.rs	70.00%	0 Missing and 3 partials ⚠️
tket-qsystem/src/extension/qsystem/barrier.rs	0.00%	1 Missing ⚠️
tket/src/modifier/modifier_resolver.rs	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1429      +/-   ##
==========================================
+ Coverage   79.56%   79.98%   +0.42%     
==========================================
  Files         155      155              
  Lines       20245    20204      -41     
  Branches    19254    19213      -41     
==========================================
+ Hits        16107    16160      +53     
+ Misses       3186     3090      -96     
- Partials      952      954       +2

Flag	Coverage Δ
python	`93.00% <ø> (ø)`
qis-compiler	`91.66% <100.00%> (-2.09%)`	⬇️
rust	`79.31% <67.95%> (+0.44%)`	⬆️

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.

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Updates the hugr dependencies to `0.26.0`, and fixes all the breaking changes. I only added no-op stubs implementing `WithScope` for the local passes. We will add the actual implementation in #1429. Requires updating LLVM too, so we should merge #1422 into this PR. We also need to delete the now removed `stack_array` lowering. BREAKING CHANGE: Updated public `hugr` dependency to `0.26.0`. Requires a `hugr-passes 0.26.1` patch release to include Quantinuum/hugr#2954 --------- Co-authored-by: George Hodgkins <[email protected]> Co-authored-by: Jake Arkinstall <[email protected]>

aborgna-q · 2026-03-19T12:19:35Z

tket-qsystem/src/lib.rs

This diff is a bit noisy since I cleaned up the definitions, but the logic should be the same;
we are just passing the scope to the internal calls, and using scope.root instead of the entrypoint in force_order.

aborgna-q · 2026-03-19T12:29:08Z

qis-compiler/python/tests/test_basic_generation.py

With the scope updates we can now re-enable this test.

I commented out the GPU test since it just lowers to an empty program, and there is no guppy definition from where to re-generate the Hugr.

Review recommendation:

acl-cqc

Thanks @aborgna-q this looks great - only one significant concern: https://github.com/Quantinuum/tket2/pull/1429/changes#r2974713146 which I think can be addressed by doing the (legacy!) "module-root support" much earlier, although have a think about whether we really wanna allow doing QSystemPass on an entrypoint scope.

Other than that a bunch of nits but nothing at all major :-)

tket-qsystem/src/extension/qsystem/lower.rs

acl-cqc · 2026-03-23T11:56:17Z

tket-qsystem/src/extension/qsystem/lower.rs

+///
 /// Returns an error if the replacement fails.
-pub fn lower_tk2_op(hugr: &mut impl HugrMut<Node = Node>) -> Result<Vec<Node>, LowerTk2Error> {
+pub fn lower_tk2_op(


drive-by super-nit: this really should be lower_tk2_ops, there are many of them, it does not take an argument saying which one to lower!

Renamed it. This is a breaking change already, so not bothering with deprecation.

tket-qsystem/src/extension/qsystem/lower.rs

acl-cqc · 2026-03-23T11:58:47Z

tket-qsystem/src/extension/qsystem/lower.rs

+                // Only perform multi-op replacement for global passes, as we
+                // cannot define new functions for local entrypoint scopes.
+                if let PassScope::Global(_) = scope {
+                    let template = match funcs.entry(tket_op) {


isn't this funcs.entry(tket_op).get_or_insert_with(|| ...).clone()

Almost, because build_func returns a Result.

acl-cqc · 2026-03-23T12:25:44Z

tket-qsystem/src/lib.rs

+            self.force_order(hugr)?;
+        }
+
+        // Backwards compatibility: If the entrypoint is a module, find a function named "main" and set that as


Yeah, so if we are running with PassScope::Entrypoint(Flat|Recursive) and the entrypoint is the module, then we've been doing nothing up to this point, and now we suddenly start running on just the main function...

I slightly question whether it even makes sense to run this on an entrypoint scope, i.e. whether this should even be a ComposablePass (or should just take a Preserve - to distinguish between library/executable modes); indeed whether it makes sense to run this on a library, or only post-linking. (Ok if we want to do LLVM linking then probably we do want to run this in library mode first).

I mean, we say "expects the hugr to have a function entrypoint" - and if it doesn't, we'll error if we don't have a main. So (a) might want to mention this legacy support in the doc (or might not!); (b) we are committed not to be compiling a library, so definitely should use Preserve::Entrypoint (even if not in this PR), but def. should do this at the beginning I think.

I do prefer having a standardized definition for passes. Perhaps we should have defined a "only global" pass type, but an alternative here could be just erroring out when called with a local scope (to avoid the user dealing with unexpected behaviour).

At this point I'm not sure what workflows are depending on the backwards compatibility for module entrypoints.
I didn't want to break things in this PR, but I agree that we should be erroring out if the entrypoint is not a function.
That may need some extra discussion and testing though to make sure we don't break downstream. I'll open an issue to decide what we should do here, but merge this with the compat option still in.

acl-cqc · 2026-03-23T12:27:16Z

tket/src/modifier/modifier_resolver.rs

    use ModifierResolverErrors::*;

-    let entry_points: VecDeque<_> = entry_points.into_iter().collect();
+    let entry_points: Vec<_> = entry_points.into_iter().collect();


Why have you changed this VecDeque -> Vec ?

It was a leftover from a previous change. Rolled it back to VecDeque.

acl-cqc · 2026-03-23T12:29:35Z

tket/src/passes/borrow_squash.rs

+        while let Some(region) = regions.pop_front() {
+            let is_dataflow_region = OpTag::DataflowParent >= hugr.get_optype(region).tag();
+            seen.clear();
+            local_queue.clear();


nit: define local_queue here, then no need to clear it. (We end with a while let Some(...) = local_queue.pop() so it really should be empty anyway)

Maybe call it op_queue too

It's a simple opt to avoid reallocating memory on every loop.
We can just reuse the container instead.

acl-cqc · 2026-03-23T12:32:31Z

tket/src/passes/borrow_squash.rs

-                    .flat_map(|n| all_outs(hugr, n)),
-            );
+            for child in hugr.children(region) {
+                // If the node is not reachable along dataflow edges from other nodes,


I think this just repeats the comment two lines before

tket/src/passes/guppy.rs

## 🤖 New release * `tket`: 0.17.0 -> 0.18.0 (✓ API compatible changes) * `tket-qsystem`: 0.23.0 -> 0.24.0 (✓ API compatible changes) <details><summary>Changelog</summary> ## `tket` <blockquote> ## [0.18.0](tket-v0.17.0...tket-v0.18.0) - 2026-04-02 ### Bug Fixes - *(pytket decoder)* Panic on repeated bit registers in pytket decoded output ([#1445](#1445)) - pytket encoder drops order edges to the output node ([#1466](#1466)) ### Documentation - Fix tket README introductory example ([#1463](#1463)) ### New Features - [**breaking**] Use raw Hugrs in pytket encoding/decoding API ([#1418](#1418)) - [**breaking**] Remove unused `lower_to_pytket` pass ([#1431](#1431)) - [**breaking**] Replace CircuitHash with hugr's implementation ([#1420](#1420)) - [**breaking**] Update MSRV to rust 1.91 ([#1446](#1446)) - [**breaking**] Update to hugr 0.26.0 ([#1448](#1448)) - [**breaking**] Follow pass scopes in composable passes ([#1429](#1429)) - Implemented `post_opdef` for `RotationOp` for constant folding ([#1468](#1468)) - [**breaking**] Reorganize `tket::passes` and add `hugr_passes` re-exports ([#1472](#1472)) - [**breaking**] Bump `hugr` dependency to 0.27.0 ([#1488](#1488)) - Move hugr-passes implementations to tket::passes ([#1487](#1487)) - Pass scopes in python API, update to hugr-py 0.16 ([#1464](#1464)) ### Refactor - *(llvm)* use llvm.is.fpclass for from_halfturns ([#1457](#1457)) ### Testing - Fixed signatures when decoding pytket circuits ([#1405](#1405)) </blockquote> ## `tket-qsystem` <blockquote> ## [0.24.0](tket-qsystem-v0.23.0...tket-qsystem-v0.24.0) - 2026-04-02 ### Bug Fixes - pytket encoder drops order edges to the output node ([#1466](#1466)) - Constant Folding with PassScope::Global should act globally, not just beneath the entrypoint ([#1470](#1470)) ### New Features - [**breaking**] Use raw Hugrs in pytket encoding/decoding API ([#1418](#1418)) - Add qsystem.rz pytket decoder ([#1432](#1432)) - [**breaking**] Update MSRV to rust 1.91 ([#1446](#1446)) - [**breaking**] Update to hugr 0.26.0 ([#1448](#1448)) - [**breaking**] Follow pass scopes in composable passes ([#1429](#1429)) - [**breaking**] Reorganize `tket::passes` and add `hugr_passes` re-exports ([#1472](#1472)) - Move hugr-passes implementations to tket::passes ([#1487](#1487)) </blockquote> </details> --- This PR was generated with [release-plz](https://github.com/release-plz/release-plz/). --------- Co-authored-by: Agustín Borgna <[email protected]>

aborgna-q mentioned this pull request Mar 2, 2026

Migrate passes to use the new PassScope Quantinuum/hugr#2771

Closed

3 tasks

aborgna-q force-pushed the ab/pass-scopes branch from a337a40 to 6119e18 Compare March 2, 2026 14:08

aborgna-q requested a review from acl-cqc March 3, 2026 15:50

aborgna-q added this to the tket-py v0.13.0 milestone Mar 4, 2026

aborgna-q mentioned this pull request Mar 16, 2026

feat!: Update to hugr 0.26.0 #1448

Merged

aborgna-q force-pushed the ab/pass-scopes branch from ca4ba4b to 8620e7e Compare March 16, 2026 15:43

aborgna-q changed the base branch from main to ab/hugr-0.26.0 March 16, 2026 15:43

aborgna-q force-pushed the ab/hugr-0.26.0 branch 10 times, most recently from cb4d32c to 2b29cdb Compare March 18, 2026 17:25

Base automatically changed from ab/hugr-0.26.0 to main March 19, 2026 10:33

aborgna-q added 6 commits March 19, 2026 10:39

BorrowSquash with_scope

70103a6

NormalizeGuppy with_scope

7ff9f2a

fixup! BorrowSquash with_scope

d732aa4

ModifierResolverPass with_scope

4db7cec

qsystem passes

20c9937

Post-rebase fix

899a12e

aborgna-q force-pushed the ab/pass-scopes branch from 8620e7e to 899a12e Compare March 19, 2026 10:49

aborgna-q commented Mar 19, 2026

View reviewed changes

Make QSystemPass a composable pass

558bc91

aborgna-q force-pushed the ab/pass-scopes branch from e6b696e to 558bc91 Compare March 19, 2026 12:20

Re-enable guppy llvm lowering test

7597302

aborgna-q commented Mar 19, 2026

View reviewed changes

aborgna-q marked this pull request as ready for review March 19, 2026 12:29

aborgna-q requested a review from a team as a code owner March 19, 2026 12:29

fix doclink

9022b03

cgh-qtnm mentioned this pull request Mar 20, 2026

fix: Bring IntoEnumIterator into scope for ops defined in tket2 #1462

Closed

acl-cqc approved these changes Mar 23, 2026

View reviewed changes

Review comments

f55c27f

aborgna-q added this pull request to the merge queue Mar 23, 2026

Merged via the queue into main with commit ae0016c Mar 23, 2026
23 of 24 checks passed

aborgna-q deleted the ab/pass-scopes branch March 23, 2026 16:30

This was referenced Mar 20, 2026

chore(py): release qis-compiler 0.3.0 #1381

Draft

chore(py): release tket-py 0.13.0 #1388

Draft

chore: release #1394

Merged

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aborgna-q commented Mar 2, 2026 •

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