Refactor Statement to keep track of component names

[ilyalesokhin-starkware]

Change get_components() on the Statement trait to return an
IndexMap<&'static str, Box<dyn CircuitEval>> so each component
carries a stable name alongside its constraint evaluator. Update all
implementors (CircuitStatement, CairoStatement, SimpleStatement) and
call sites accordingly.

Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com

[cursor]

PR Summary

Medium Risk
Touches core verifier/statement plumbing by changing Statement::get_components() and propagating IndexMap ordering through proof config and verification loops; a mismatch in component ordering/naming could break proof verification even though logic is mostly refactor.

Overview
Refactors the Statement interface to carry a stable component name alongside each CircuitEval by returning an IndexMap<&'static str, Box<dyn CircuitEval<_>>> instead of a Vec/slice.

Updates all statement implementations and call sites (Cairo verifier, circuit AIR statement, and examples) to build/iterate components via IndexMap (typically values()), and adjusts indexing-based logic to use IndexMap lookups by name.

Adds indexmap as a dependency where needed and updates ProofConfig::from_components and verifier composition evaluation loops to consume components from the map deterministically.

^{Reviewed by Cursor Bugbot for commit c8a1958. Bugbot is set up for automated code reviews on this repo. Configure here.}

[reviewable-StarkWare]

This change is 

[ilyalesokhin-starkware]

• Add enabled_bits to ProofConfig #453
• Refactor Statement to keep track of component names #455 👈 (View in Graphite)
• main

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

[Gali-StarkWare]

@Gali-StarkWare reviewed 1 file and all commit messages, and made 1 comment.
Reviewable status: 1 of 13 files reviewed, 1 unresolved discussion (waiting on ilyalesokhin-starkware and leo-starkware).

---

Cargo.lock line 1277 at r1 (raw file):

 "circuits-stark-verifier",
 "expect-test",
 "indexmap",

Is it related? I don't see the toml change

Code quote:

 "indexmap",

[Gali-StarkWare]

@Gali-StarkWare made 1 comment.
Reviewable status: 1 of 13 files reviewed, 1 unresolved discussion (waiting on ilyalesokhin-starkware and leo-starkware).

---

Cargo.lock line 1277 at r1 (raw file):

Previously, Gali-StarkWare wrote…

Is it related? I don't see the toml change

nvm

[Gali-StarkWare]

@Gali-StarkWare resolved 1 discussion.
Reviewable status: 1 of 13 files reviewed, all discussions resolved (waiting on leo-starkware).

[Gali-StarkWare]

@Gali-StarkWare reviewed 12 files and made 2 comments.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on ilyalesokhin-starkware and leo-starkware).

---

crates/circuit_air/src/statement.rs line 145 at r1 (raw file):

{
    IndexMap::from([
        ("eq", Box::new(CircuitEqComponent {}) as Box<dyn CircuitEval<Value>>),

Maybe eq_gate is better? Or does is require changes elsewhere?

Code quote:

"eq"

[Gali-StarkWare]

So why do we need the names?

@Gali-StarkWare made 1 comment.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on ilyalesokhin-starkware and leo-starkware).

[ilyalesokhin-starkware]

I need it in the next PR, here:

stwo-circuits/crates/cairo_air/src/statement.rs

Line 229 in 6ac0490

let Some(index) = self.components.get_index_of(name) else {

[ilyalesokhin-starkware]

crates/circuit_air/src/statement.rs line 145 at r1 (raw file):

Previously, Gali-StarkWare wrote…

Maybe eq_gate is better? Or does is require changes elsewhere?

it is called eq in the infra:

stwo-circuits/crates/circuit_air/src/components/eq.rs

Line 70 in 56c9f27

"eq".to_string()

)

[ilyalesokhin-starkware]

@ilyalesokhin-starkware resolved 1 discussion.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on leo-starkware).

[Gali-StarkWare]

Reviewable status: complete! all files reviewed, all discussions resolved (waiting on leo-starkware).

[Gali-StarkWare]

@Gali-StarkWare made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on leo-starkware).