refact(es/minifier): Inline into shorthand prop early by Austaras · Pull Request #11766 · swc-project/swc

Austaras · 2026-04-03T10:09:24Z

Description:

BREAKING CHANGE:

Related issue (if exists):

changeset-bot · 2026-04-03T10:09:31Z

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Latest commit: ca4951d

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Pull request overview

Refactors the minifier’s inlining logic to support inlining into object-literal shorthand properties earlier, while preserving correct __proto__ semantics.

Changes:

Exposes prop_name_from_ident so other optimizer passes can safely expand shorthand props (handling __proto__ via computed keys).
Adds a visit_mut_prop hook to inline identifiers inside Prop::Shorthand and convert them to KeyValueProp.
Extracts identifier inlining logic into a reusable inline_ident helper and reuses it from inline().

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
crates/swc_ecma_minifier/src/compress/optimize/util.rs	Makes `prop_name_from_ident` available for shorthand→key-value expansion while preserving `__proto__` behavior.
crates/swc_ecma_minifier/src/compress/optimize/mod.rs	Adds shorthand property inlining during AST visitation and expands shorthand into key-value props.
crates/swc_ecma_minifier/src/compress/optimize/inline.rs	Refactors identifier inlining into `inline_ident` and calls it from expression inlining.

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crates/swc_ecma_minifier/src/compress/optimize/inline.rs

Copilot · 2026-04-03T10:13:04Z

crates/swc_ecma_minifier/src/compress/optimize/mod.rs

+                *n = Prop::KeyValue(KeyValueProp {
+                    key,
+                    value: expr.clone(),
+                });


expr is owned here (returned from inline_ident), but it’s cloned when building KeyValueProp. This adds avoidable allocation/AST cloning; move expr into value instead of cloning it.

Suggested change

*n = Prop::KeyValue(KeyValueProp {

key,

value: expr.clone(),

});

*n = Prop::KeyValue(KeyValueProp { key, value: expr });

Copilot · 2026-04-03T10:13:04Z

crates/swc_ecma_minifier/src/compress/optimize/inline.rs

+
+        if let Some(value) = self.vars.vars_for_inlining.remove(&id) {
+            self.changed = true;
+            report_change!("inline: Replacing '{}' with an expression", i);


Same issue as above: this report_change! call uses i, which is not defined in inline_ident. Use ident (or an Id derived from it) so this compiles and logs the correct identifier.

Suggested change

report_change!("inline: Replacing '{}' with an expression", i);

report_change!("inline: Replacing '{}' with an expression", ident.sym);

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chatgpt-codex-connector · 2026-04-03T10:14:38Z

crates/swc_ecma_minifier/src/compress/optimize/inline.rs

-                    self.changed = true;
-                    report_change!("inline: Replacing '{}' with an expression", i);
+            self.changed = true;
+            report_change!("inline: Replacing a variable `{}` with cheap expression", i);


Replace stale i reference in inline_ident logging

After extracting inline_ident, the logging calls still format {} with i, but this function only has ident; when the debug feature is enabled, report_change! expands to tracing::debug! and this becomes an unresolved identifier compile error. This breaks swc_ecma_minifier builds in debug-feature workflows (e.g. cargo check -p swc_ecma_minifier --features debug).

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github-actions · 2026-04-03T10:18:56Z

Binary Sizes

File	Size
`swc.linux-x64-gnu.node`	28M (29075272 bytes)

Commit: 0d8ba38

codspeed-hq · 2026-04-03T10:26:39Z

Merging this PR will not alter performance

✅ 219 untouched benchmarks

_{Comparing Austaras:main (ca4951d) with main (236eff0)¹}

No successful run was found on main (87dee57) during the generation of this report, so 236eff0 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

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Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

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Copilot · 2026-04-03T16:49:30Z

crates/swc_ecma_minifier/src/compress/optimize/util.rs

 /// `__proto__`. When the property name is `__proto__`, it must be converted to
 /// a computed property to preserve JavaScript semantics.
-fn prop_name_from_ident(ident: Ident) -> PropName {
+pub(crate) fn prop_name_from_ident(ident: Ident) -> PropName {


prop_name_from_ident is only referenced within the compress::optimize module (currently optimize/mod.rs and this file). Exposing it as pub(crate) increases the crate-wide API surface unnecessarily; consider reducing visibility to pub(super) (or pub(in crate::compress::optimize)) to keep the helper scoped to this module.

Suggested change

pub(crate) fn prop_name_from_ident(ident: Ident) -> PropName {

pub(super) fn prop_name_from_ident(ident: Ident) -> PropName {

kdy1 · 2026-04-07T05:33:44Z

Can you make tests I added pass?

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Copilot reviewed 50 out of 50 changed files in this pull request and generated no new comments.

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Austaras requested a review from a team as a code owner April 3, 2026 10:09

Copilot AI review requested due to automatic review settings April 3, 2026 10:09

Copilot started reviewing on behalf of Austaras April 3, 2026 10:10 View session

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Austaras force-pushed the main branch from d5419cf to 4ce9aa4 Compare April 3, 2026 10:33

refact(es/minifier): Inline into shorthand prop early

6a3f79a

Copilot AI review requested due to automatic review settings April 3, 2026 16:44

Austaras force-pushed the main branch from 4ce9aa4 to 6a3f79a Compare April 3, 2026 16:44

Copilot started reviewing on behalf of Austaras April 3, 2026 16:45 View session

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test(minifier): add shorthand inline regression coverage

77ab186

fix renamer

ca4951d

Copilot AI review requested due to automatic review settings April 7, 2026 07:57

Copilot started reviewing on behalf of Austaras April 7, 2026 07:58 View session

Copilot AI reviewed Apr 7, 2026

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refact(es/minifier): Inline into shorthand prop early#11766

refact(es/minifier): Inline into shorthand prop early#11766
Austaras wants to merge 3 commits intoswc-project:mainfrom
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	report_change!("inline: Replacing '{}' with an expression", i);
	report_change!("inline: Replacing '{}' with an expression", ident.sym);

	pub(crate) fn prop_name_from_ident(ident: Ident) -> PropName {
	pub(super) fn prop_name_from_ident(ident: Ident) -> PropName {

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