From 6003285cfe33f233d3c0c97374c3ad87f9f8ebc2 Mon Sep 17 00:00:00 2001
From: sapphi-red <49056869+sapphi-red@users.noreply.github.com>
Date: Sun, 24 Aug 2025 08:42:50 +0000
Subject: [PATCH] fix(minifier): keep property access before call expressions
 as-is to preserve `this` value (#13278)

`['PASS',f][1]()` was compressed to `f()`. But this is not safe because `f` may access `this` and the value of `this` changes.
This PR fixes that by skipping this transformation when the parent is a function call.
---
 .../src/peephole/replace_known_methods.rs     | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/crates/oxc_minifier/src/peephole/replace_known_methods.rs b/crates/oxc_minifier/src/peephole/replace_known_methods.rs
index 827cc07969f30..7d0c8f2cac568 100644
--- a/crates/oxc_minifier/src/peephole/replace_known_methods.rs
+++ b/crates/oxc_minifier/src/peephole/replace_known_methods.rs
@@ -357,6 +357,14 @@ impl<'a> PeepholeOptimizations {
     }
 
     pub fn replace_known_property_access(node: &mut Expression<'a>, ctx: &mut Ctx<'a, '_>) {
+        // property access should be kept to keep `this` value
+        if matches!(
+            ctx.parent(),
+            Ancestor::CallExpressionCallee(_) | Ancestor::TaggedTemplateExpressionTag(_)
+        ) {
+            return;
+        }
+
         let (name, object, span) = match node {
             Expression::StaticMemberExpression(member) if !member.optional => {
                 (member.property.name.as_str(), &member.object, member.span)
@@ -1612,6 +1620,20 @@ mod test {
         test_same("v = [...a, 1][1]");
         test_same("v = [1, ...a][0]");
         test("v = [1, ...[1,2]][0]", "v = 1");
+
+        // property access should be kept to keep `this` value
+        test_same(
+            "
+            function f(){ console.log(this[0]) }
+            ['PASS',f][1]()
+        ",
+        );
+        test_same(
+            "
+            function f(){ console.log(this[0]) }
+            ['PASS',f][1]``
+        ",
+        );
     }
 
     #[test]