refactor: shorten AST builder code by overlookmotel · Pull Request #10418 · rolldown/rolldown

overlookmotel · 2026-07-23T22:54:42Z

Follow-on after #10018.

First of a series of PRs all grouped around 2 themes:

Shorten code using AST builder methods.
Reduce string allocations.

The new AST builder methods allow shortened syntax. Utilize the shorter methods wherever possible.

Before:

ast::Statement::ExpressionStatement(ast::ExpressionStatement::boxed(span, call_expr, &self.ast_builder))

After:

ast::Statement::new_expression_statement(span, call_expr, &self.ast_builder)

Note: Diff is quite large, but these changes were almost entirely produced using the same deterministic codemod we used to migrate Oxc repo to new AST builder, with only some final tweaks by an LLM. I've reviewed it all and, even though I'm unfamiliar with Rolldown's codebase, I'm pretty confident it looks correct.

overlookmotel · 2026-07-23T22:54:58Z

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netlify · 2026-07-23T22:55:02Z

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Copilot

Pull request overview

This PR continues the oxc 0.138 AST-construction migration by refactoring call sites to use the newer shortened new_* constructors (e.g. Expression::new_call_expression, Statement::new_expression_statement) instead of manual enum wrapping + ::boxed(...). The goal is primarily to reduce verbosity while keeping generated AST identical.

Changes:

Replaced many EnumVariant(Type::boxed(...)) AST constructions with Type::new_* / Enum::new_* helpers across core, HMR, and plugin crates.
Updated common AST utility helpers (ast_factory, binding pattern/property extensions) to use the shortened construction APIs.
Adjusted JSON-to-AST object property key construction to use PropertyKey::new_string_literal directly.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
crates/rolldown/src/utils/tweak_ast_for_scanning.rs	Switches statement/expression construction to `Statement::new_` / `Expression::new_` helpers.
crates/rolldown/src/stages/link_stage/generate_lazy_export.rs	Uses shortened `PropertyKey` construction for object properties.
crates/rolldown/src/module_finalizers/rename.rs	Simplifies assignment-target identifier construction.
crates/rolldown/src/module_finalizers/mod.rs	Large set of AST-construction refactors for finalizer-generated code paths (imports/exports/runtime helpers).
crates/rolldown/src/module_finalizers/impl_visit_mut.rs	Refactors statement construction in VisitMut transformations.
crates/rolldown/src/hmr/utils.rs	Uses shortened constructors for HMR-injected AST fragments.
crates/rolldown/src/hmr/impl_traverse_for_hmr_ast_finalizer.rs	Refactors traversal-produced AST nodes to use `new_*` helpers (try stmt, calls, literals).
crates/rolldown/src/hmr/hmr_ast_finalizer.rs	Refactors HMR finalizer AST building to shortened constructors.
crates/rolldown_plugin_vite_web_worker_post/src/ast_visitor.rs	Updates plugin’s AST visitor to shortened member/object/property constructors.
crates/rolldown_plugin_vite_build_import_analysis/src/ast_visit.rs	Refactors import-helper insertion to use `Statement::new_import_declaration`.
crates/rolldown_plugin_vite_build_import_analysis/src/ast_utils.rs	Updates preload-call construction and related AST helpers to use `new_*` APIs.
crates/rolldown_plugin_lazy_compilation/src/runtime_injector.rs	Refactors lazy-compilation runtime injection helper AST construction.
crates/rolldown_ecmascript_utils/src/extensions/ast_ext/binding_property_ext.rs	Refactors binding-property → assignment-target-property conversion to new constructors.
crates/rolldown_ecmascript_utils/src/extensions/ast_ext/binding_pattern_ext.rs	Refactors binding-pattern conversions and expression emission to new constructors.
crates/rolldown_ecmascript_utils/src/ast_factory.rs	Refactors shared AST factory helpers (then/arrow/call/member/property/statement builders) to new constructors.
crates/rolldown_common/src/ecmascript/json_to_program.rs	Uses `PropertyKey::new_string_literal` directly for JSON object keys.

codspeed-hq · 2026-07-23T23:16:19Z

Merging this PR will not alter performance

✅ 7 untouched benchmarks
⏩ 10 skipped benchmarks¹

_{Comparing om/07-23-refactor_shorten_ast_builder_code (8e20bae) with main (4de88b1)²}

10 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. ↩
No successful run was found on main (99948b5) during the generation of this report, so 4de88b1 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

hyfdev

— Review by @hyfdev, assisted by GPT-5

graphite-app · 2026-07-24T03:38:44Z

Merge activity

Jul 24, 3:38 AM UTC: hyfdev added this pull request to the Graphite merge queue.
Jul 24, 3:50 AM UTC: Merged by the Graphite merge queue.

Follow-on after #10018. First of a series of PRs all grouped around 2 themes: 1. Shorten code using AST builder methods. 2. Reduce string allocations. The new AST builder methods allow shortened syntax. Utilize the shorter methods wherever possible. Before: ```rust ast::Statement::ExpressionStatement(ast::ExpressionStatement::boxed(span, call_expr, &self.ast_builder)) ``` After: ```rust ast::Statement::new_expression_statement(span, call_expr, &self.ast_builder) ``` Note: Diff is quite large, but these changes were almost entirely produced using the same [deterministic codemod](https://github.com/oxc-project/oxc/tree/overlookmotel/ast-builder-codemod) we used to migrate Oxc repo to new AST builder, with only some final tweaks by an LLM. I've reviewed it all and, even though I'm unfamiliar with Rolldown's codebase, I'm pretty confident it looks correct.

Follow-on after #10018. The new AST builder methods allow passing arrays where a `Vec` is required. Use this facility to remove a lot of repetitious boilerplate. Before: ```rust FunctionBody::new( SPAN, oxc::allocator::Vec::new_in(&self.ast_builder), oxc::allocator::Vec::from_value_in(try_stmt, &self.ast_builder), &self.ast_builder, ) ``` After: ```rust FunctionBody::new(SPAN, [], [try_stmt], &self.ast_builder) ``` Note: Like #10418, diff is quite large, but these changes were almost entirely produced using the same [deterministic codemod](https://github.com/oxc-project/oxc/tree/overlookmotel/ast-builder-codemod) we used to migrate Oxc repo to new AST builder, with only some final tweaks by an LLM. I've reviewed it all and, even though I'm unfamiliar with Rolldown's codebase, I'm pretty confident it looks correct.

This was referenced Jul 23, 2026

perf: reduce string allocations #10423

Merged

refactor: implement GetAstBuilder on visitor/pass types #10424

Merged

perf(scope_hoisting): remove alloc field from ScopeHoistingFinalizer #10425

Merged

overlookmotel marked this pull request as ready for review July 23, 2026 23:08

overlookmotel requested a review from h-a-n-a as a code owner July 23, 2026 23:08

Copilot AI review requested due to automatic review settings July 23, 2026 23:08

overlookmotel requested review from IWANABETHATGUY, hyfdev, sapphi-red and shulaoda as code owners July 23, 2026 23:08

Copilot started reviewing on behalf of overlookmotel July 23, 2026 23:08 View session

Copilot AI reviewed Jul 23, 2026

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Comment thread crates/rolldown/src/module_finalizers/mod.rs Outdated

overlookmotel force-pushed the om/07-23-refactor_shorten_ast_builder_code branch from 4e5b677 to 8e20bae Compare July 24, 2026 00:02

IWANABETHATGUY approved these changes Jul 24, 2026

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hyfdev approved these changes Jul 24, 2026

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graphite-app Bot added the graphite: merge-when-ready label Jul 24, 2026

graphite-app Bot force-pushed the om/07-23-refactor_shorten_ast_builder_code branch from 8e20bae to 9886244 Compare July 24, 2026 03:43

graphite-app Bot merged commit 9886244 into main Jul 24, 2026
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graphite-app Bot removed the graphite: merge-when-ready label Jul 24, 2026

graphite-app Bot deleted the om/07-23-refactor_shorten_ast_builder_code branch July 24, 2026 03:50

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