From 7e6ec8d587471dba1dde44ebcfd6af6d03247955 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: Tue, 20 Dec 2022 16:45:29 +0900
Subject: [PATCH] fix(es/minifier): Don't inline invalid LHS into an update
 argument (#6680)

**Related issue:**

 - Closes https://github.com/swc-project/swc/issues/6641.
---
 .../src/compress/optimize/inline.rs                 |  5 +++++
 .../swc_ecma_minifier/src/compress/optimize/mod.rs  |  6 ++++++
 crates/swc_ecma_minifier/tests/exec.rs              | 13 +++++++++++++
 3 files changed, 24 insertions(+)

diff --git a/crates/swc_ecma_minifier/src/compress/optimize/inline.rs b/crates/swc_ecma_minifier/src/compress/optimize/inline.rs
index 51e37a4c977f..f463702119ee 100644
--- a/crates/swc_ecma_minifier/src/compress/optimize/inline.rs
+++ b/crates/swc_ecma_minifier/src/compress/optimize/inline.rs
@@ -733,6 +733,11 @@ where
                 })
                 .cloned()
             {
+                if !matches!(&*value, Expr::Ident(..) | Expr::Member(..)) && self.ctx.is_update_arg
+                {
+                    return;
+                }
+
                 self.changed = true;
                 report_change!("inline: Replacing a variable `{}` with cheap expression", i);
 
diff --git a/crates/swc_ecma_minifier/src/compress/optimize/mod.rs b/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
index b508e20edc3f..a3e2200f4601 100644
--- a/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
+++ b/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
@@ -1536,6 +1536,7 @@ where
                     },
                 is_lhs_of_assign: false,
                 is_exact_lhs_of_assign: false,
+                is_update_arg: false,
                 ..self.ctx
             };
             e.callee.visit_mut_with(&mut *self.with_ctx(ctx));
@@ -1566,6 +1567,7 @@ where
                 is_this_aware_callee: false,
                 is_lhs_of_assign: false,
                 is_exact_lhs_of_assign: false,
+                is_update_arg: false,
                 ..self.ctx
             };
             // TODO: Prevent inline if callee is unknown.
@@ -1583,6 +1585,7 @@ where
         {
             let ctx = Ctx {
                 dont_invoke_iife: true,
+                is_update_arg: false,
                 ..self.ctx
             };
             n.super_class.visit_mut_with(&mut *self.with_ctx(ctx));
@@ -1591,6 +1594,7 @@ where
         {
             let ctx = Ctx {
                 in_strict: true,
+                is_update_arg: false,
                 ..self.ctx
             };
             n.body.visit_mut_with(&mut *self.with_ctx(ctx));
@@ -2184,6 +2188,7 @@ where
             let ctx = Ctx {
                 in_obj_of_non_computed_member: !n.prop.is_computed(),
                 is_exact_lhs_of_assign: false,
+                is_update_arg: false,
                 ..self.ctx
             };
             n.obj.visit_mut_with(&mut *self.with_ctx(ctx));
@@ -2192,6 +2197,7 @@ where
             let ctx = Ctx {
                 is_exact_lhs_of_assign: false,
                 is_lhs_of_assign: false,
+                is_update_arg: false,
                 ..self.ctx
             };
             c.visit_mut_with(&mut *self.with_ctx(ctx));
diff --git a/crates/swc_ecma_minifier/tests/exec.rs b/crates/swc_ecma_minifier/tests/exec.rs
index a00ad7941c36..c609814dd320 100644
--- a/crates/swc_ecma_minifier/tests/exec.rs
+++ b/crates/swc_ecma_minifier/tests/exec.rs
@@ -10394,3 +10394,16 @@ fn issue_6528() {
         "###,
     )
 }
+
+#[test]
+fn issue_6641() {
+    run_default_exec_test(
+        r###"
+        const iota = (i => () => 1 << ++i)(-1);
+
+        const a = iota(), b = iota();
+            
+        console.log(a, b);
+        "###,
+    )
+}