From 88d40e8ab899976c123b5b5f74f0ad02ec9d7868 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, 4 Jan 2023 13:31:12 +0900
Subject: [PATCH] fix(es/minifier): Fix usage counter to fix infinite loop
 (#6744)

**Description:**

We skip non-computed property names while checking if we can inline an expression.

**Related issue:**

 - Closes https://github.com/swc-project/swc/issues/6729.
---
 .../fixture/issues-6xxx/6729/input/.swcrc     | 19 +++++++++++++++
 .../fixture/issues-6xxx/6729/input/index.js   | 13 ++++++++++
 .../fixture/issues-6xxx/6729/output/index.js  |  5 ++++
 .../src/compress/optimize/sequences.rs        | 24 ++++++++++++-------
 crates/swc_ecma_minifier/tests/exec.rs        | 22 +++++++++++++++++
 5 files changed, 74 insertions(+), 9 deletions(-)
 create mode 100644 crates/swc/tests/fixture/issues-6xxx/6729/input/.swcrc
 create mode 100644 crates/swc/tests/fixture/issues-6xxx/6729/input/index.js
 create mode 100644 crates/swc/tests/fixture/issues-6xxx/6729/output/index.js

diff --git a/crates/swc/tests/fixture/issues-6xxx/6729/input/.swcrc b/crates/swc/tests/fixture/issues-6xxx/6729/input/.swcrc
new file mode 100644
index 000000000000..578baada5531
--- /dev/null
+++ b/crates/swc/tests/fixture/issues-6xxx/6729/input/.swcrc
@@ -0,0 +1,19 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "typescript",
+            "decorators": true,
+            "tsx": false
+        },
+        "target": "es2020",
+        "loose": false,
+        "minify": {
+            "compress": true,
+            "mangle": false
+        }
+    },
+    "module": {
+        "type": "es6"
+    },
+    "isModule": true
+}
\ No newline at end of file
diff --git a/crates/swc/tests/fixture/issues-6xxx/6729/input/index.js b/crates/swc/tests/fixture/issues-6xxx/6729/input/index.js
new file mode 100644
index 000000000000..157ca8510bfe
--- /dev/null
+++ b/crates/swc/tests/fixture/issues-6xxx/6729/input/index.js
@@ -0,0 +1,13 @@
+export async function foo() {
+    if (undefined_var_1) {
+        let replace;
+
+        if (undefined_var_2) {
+            replace = 1;
+        } else {
+            replace = 2;
+        }
+
+        await a({ replace })
+    }
+}
diff --git a/crates/swc/tests/fixture/issues-6xxx/6729/output/index.js b/crates/swc/tests/fixture/issues-6xxx/6729/output/index.js
new file mode 100644
index 000000000000..baa943f7394b
--- /dev/null
+++ b/crates/swc/tests/fixture/issues-6xxx/6729/output/index.js
@@ -0,0 +1,5 @@
+export async function foo() {
+    undefined_var_1 && await a({
+        replace: undefined_var_2 ? 1 : 2
+    });
+}
diff --git a/crates/swc_ecma_minifier/src/compress/optimize/sequences.rs b/crates/swc_ecma_minifier/src/compress/optimize/sequences.rs
index d24c59c6d53d..ca9b6db5e423 100644
--- a/crates/swc_ecma_minifier/src/compress/optimize/sequences.rs
+++ b/crates/swc_ecma_minifier/src/compress/optimize/sequences.rs
@@ -2444,15 +2444,6 @@ impl Visit for UsageCounter<'_> {
         }
     }
 
-    fn visit_super_prop_expr(&mut self, e: &SuperPropExpr) {
-        if let SuperProp::Computed(c) = &e.prop {
-            let old = self.in_lhs;
-            self.in_lhs = false;
-            c.expr.visit_with(self);
-            self.in_lhs = old;
-        }
-    }
-
     fn visit_pat(&mut self, p: &Pat) {
         let old = self.in_lhs;
         self.in_lhs = true;
@@ -2466,6 +2457,21 @@ impl Visit for UsageCounter<'_> {
         p.visit_children_with(self);
         self.in_lhs = old;
     }
+
+    fn visit_prop_name(&mut self, p: &PropName) {
+        if let PropName::Computed(p) = p {
+            p.visit_with(self)
+        }
+    }
+
+    fn visit_super_prop_expr(&mut self, e: &SuperPropExpr) {
+        if let SuperProp::Computed(c) = &e.prop {
+            let old = self.in_lhs;
+            self.in_lhs = false;
+            c.expr.visit_with(self);
+            self.in_lhs = old;
+        }
+    }
 }
 
 #[derive(Debug)]
diff --git a/crates/swc_ecma_minifier/tests/exec.rs b/crates/swc_ecma_minifier/tests/exec.rs
index c609814dd320..75c6e10a1949 100644
--- a/crates/swc_ecma_minifier/tests/exec.rs
+++ b/crates/swc_ecma_minifier/tests/exec.rs
@@ -10407,3 +10407,25 @@ fn issue_6641() {
         "###,
     )
 }
+
+#[test]
+fn issue_6728() {
+    run_default_exec_test(
+        r###"
+        async function foo() {
+            if (undefined_var_1) {
+              let replace;
+            
+              if (undefined_var_2) {
+                replace = 1;
+              } else {
+                replace = 2;
+              }
+            
+              await a({ replace })
+            }
+        }
+        console.log('PASS')
+        "###,
+    )
+}