From 0eea7da1c8dc736093b22307f528123436d4621b Mon Sep 17 00:00:00 2001
From: sapphi-red <49056869+sapphi-red@users.noreply.github.com>
Date: Sun, 31 Aug 2025 15:15:49 +0000
Subject: [PATCH] fix(regular_expression): don't lower capture groups that are
 not named ones (#13469)

Capture groups that are not named ones are lowered even though it's not needed to.
---
 crates/oxc_regular_expression/src/ast_impl/support.rs       | 4 +++-
 tasks/coverage/snapshots/semantic_typescript.snap           | 4 ++--
 .../fixtures/all-regex-plugins-enabled-by-targets/input.js  | 6 +++---
 .../fixtures/all-regex-plugins-enabled-by-targets/output.js | 6 +++---
 .../transform-named-capturing-groups-regex/input.js         | 4 +++-
 .../transform-named-capturing-groups-regex/output.js        | 4 +++-
 6 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/crates/oxc_regular_expression/src/ast_impl/support.rs b/crates/oxc_regular_expression/src/ast_impl/support.rs
index 7900e63008664..12a5daa15204e 100644
--- a/crates/oxc_regular_expression/src/ast_impl/support.rs
+++ b/crates/oxc_regular_expression/src/ast_impl/support.rs
@@ -22,7 +22,9 @@ fn term_contains_unsupported(mut term: &Term, unsupported: &RegexUnsupportedPatt
     // Loop because `Term::Quantifier` contains a nested `Term`
     loop {
         match term {
-            Term::CapturingGroup(_) => return unsupported.named_capture_groups,
+            Term::CapturingGroup(group) => {
+                return group.name.is_some() && unsupported.named_capture_groups;
+            }
             Term::UnicodePropertyEscape(_) => return unsupported.unicode_property_escapes,
             Term::CharacterClass(character_class) => {
                 return unsupported.unicode_property_escapes
diff --git a/tasks/coverage/snapshots/semantic_typescript.snap b/tasks/coverage/snapshots/semantic_typescript.snap
index 16352dffe7c61..c6712e5439c0d 100644
--- a/tasks/coverage/snapshots/semantic_typescript.snap
+++ b/tasks/coverage/snapshots/semantic_typescript.snap
@@ -5918,8 +5918,8 @@ Reference symbol mismatch for "require":
 after transform: SymbolId(0) "require"
 rebuilt        : <None>
 Unresolved references mismatch:
-after transform: ["Error", "JSON", "RegExp"]
-rebuilt        : ["Error", "JSON", "RegExp", "require"]
+after transform: ["Error", "JSON"]
+rebuilt        : ["Error", "JSON", "require"]
 
 semantic Error: tasks/coverage/typescript/tests/cases/compiler/controlFlowUnionContainingTypeParameter1.ts
 Unresolved references mismatch:
diff --git a/tasks/transform_conformance/tests/regexp/test/fixtures/all-regex-plugins-enabled-by-targets/input.js b/tasks/transform_conformance/tests/regexp/test/fixtures/all-regex-plugins-enabled-by-targets/input.js
index 31519d315e94c..40bed4b16c673 100644
--- a/tasks/transform_conformance/tests/regexp/test/fixtures/all-regex-plugins-enabled-by-targets/input.js
+++ b/tasks/transform_conformance/tests/regexp/test/fixtures/all-regex-plugins-enabled-by-targets/input.js
@@ -9,11 +9,11 @@ a1 = /a.b/s
 // RegExpLookbehindAssertions
 b1 = /(?<!x)/
 b2 = /(?<=x)/
-b3 = /((?<!x)){2}/
-b4 = /((?<=x)){3}/
+b3 = /((?<!x)){2}/ // FIXME(sapphi-red): will be fixed in the next PR
+b4 = /((?<=x)){3}/ // FIXME(sapphi-red): will be fixed in the next PR
 // RegExpNamedCaptureGroups
 c1 = /(?<a>b)/
-c2 = /((?<c>d)){4}/;
+c2 = /((?<c>d)){4}/; // FIXME(sapphi-red): will be fixed in the next PR
 // RegExpUnicodePropertyEscapes
 d1 = /\p{Emoji}/u
 // ES2022
diff --git a/tasks/transform_conformance/tests/regexp/test/fixtures/all-regex-plugins-enabled-by-targets/output.js b/tasks/transform_conformance/tests/regexp/test/fixtures/all-regex-plugins-enabled-by-targets/output.js
index c430be659e84f..22c965e5bab3c 100644
--- a/tasks/transform_conformance/tests/regexp/test/fixtures/all-regex-plugins-enabled-by-targets/output.js
+++ b/tasks/transform_conformance/tests/regexp/test/fixtures/all-regex-plugins-enabled-by-targets/output.js
@@ -3,10 +3,10 @@ x2 = new RegExp(".", "u");
 a1 = new RegExp("a.b", "s");
 b1 = new RegExp("(?<!x)", "");
 b2 = new RegExp("(?<=x)", "");
-b3 = new RegExp("((?<!x)){2}", "");
-b4 = new RegExp("((?<=x)){3}", "");
+b3 = /((?<!x)){2}/;
+b4 = /((?<=x)){3}/;
 c1 = new RegExp("(?<a>b)", "");
-c2 = new RegExp("((?<c>d)){4}", "");
+c2 = /((?<c>d)){4}/;
 d1 = new RegExp("\\p{Emoji}", "u");
 f1 = new RegExp("y", "d");
 g1 = new RegExp("[\\p{White_Space}&&\\p{ASCII}]", "v");
diff --git a/tasks/transform_conformance/tests/regexp/test/fixtures/transform-named-capturing-groups-regex/input.js b/tasks/transform_conformance/tests/regexp/test/fixtures/transform-named-capturing-groups-regex/input.js
index 9b29e8fd65904..52680bf055f1a 100644
--- a/tasks/transform_conformance/tests/regexp/test/fixtures/transform-named-capturing-groups-regex/input.js
+++ b/tasks/transform_conformance/tests/regexp/test/fixtures/transform-named-capturing-groups-regex/input.js
@@ -1,2 +1,4 @@
 c1 = /(?<a>b)/
-c2 = /((?<a>b)){2}/
+c2 = /((?<a>b)){2}/ // FIXME(sapphi-red): will be fixed in the next PR
+
+n1 = /(a)/
diff --git a/tasks/transform_conformance/tests/regexp/test/fixtures/transform-named-capturing-groups-regex/output.js b/tasks/transform_conformance/tests/regexp/test/fixtures/transform-named-capturing-groups-regex/output.js
index 9ab527d8f46a2..c179c37555ea1 100644
--- a/tasks/transform_conformance/tests/regexp/test/fixtures/transform-named-capturing-groups-regex/output.js
+++ b/tasks/transform_conformance/tests/regexp/test/fixtures/transform-named-capturing-groups-regex/output.js
@@ -1,2 +1,4 @@
 c1 = new RegExp("(?<a>b)", "");
-c2 = new RegExp("((?<a>b)){2}", "");
+c2 = /((?<a>b)){2}/;
+
+n1 = /(a)/;