From e4e4d6cf6bbc2645272d590cd6ae83aeb5c19b1c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Wed, 14 Dec 2022 13:45:47 +0900
Subject: [PATCH] fix(es/minifier): Abort sequential inliner on optional
 chaining (#6637)

**Related issue:**

 - Closes https://github.com/swc-project/swc/issues/6636.
---
 .../swc_ecma_minifier/src/compress/optimize/sequences.rs  | 4 +++-
 .../tests/fixture/issues/6636/config.json                 | 7 +++++++
 .../swc_ecma_minifier/tests/fixture/issues/6636/input.js  | 8 ++++++++
 .../swc_ecma_minifier/tests/fixture/issues/6636/output.js | 4 ++++
 4 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/6636/config.json
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/6636/input.js
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/6636/output.js

diff --git a/crates/swc_ecma_minifier/src/compress/optimize/sequences.rs b/crates/swc_ecma_minifier/src/compress/optimize/sequences.rs
index d91e348f53a..d24c59c6d53 100644
--- a/crates/swc_ecma_minifier/src/compress/optimize/sequences.rs
+++ b/crates/swc_ecma_minifier/src/compress/optimize/sequences.rs
@@ -1546,7 +1546,9 @@ where
         }
 
         match b {
-            Expr::Update(..) | Expr::Arrow(..) | Expr::Fn(..) => return Ok(false),
+            Expr::Update(..) | Expr::Arrow(..) | Expr::Fn(..) | Expr::OptChain(..) => {
+                return Ok(false)
+            }
 
             Expr::Cond(b) => {
                 trace_op!("seq: Try test of cond");
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/6636/config.json b/crates/swc_ecma_minifier/tests/fixture/issues/6636/config.json
new file mode 100644
index 00000000000..fbb662f8d15
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/6636/config.json
@@ -0,0 +1,7 @@
+{
+    "passes": 2,
+    "toplevel": true,
+    "defaults": true,
+    "sequences": true,
+    "collapse_vars": true
+}
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/6636/input.js b/crates/swc_ecma_minifier/tests/fixture/issues/6636/input.js
new file mode 100644
index 00000000000..4317ff13ac0
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/6636/input.js
@@ -0,0 +1,8 @@
+export function memo(fn, opts) {
+  let result;
+  return () => {
+    result = fn(...newDeps);
+    opts?.onChange?.(result);
+    return result;
+  };
+}
\ No newline at end of file
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/6636/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/6636/output.js
new file mode 100644
index 00000000000..16e888beb4d
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/6636/output.js
@@ -0,0 +1,4 @@
+export function memo(fn, opts) {
+    let result;
+    return ()=>(result = fn(...newDeps), opts?.onChange?.(result), result);
+}