From 5a44c6b42471aeceb3771b1cf4ebb310d03a0154 Mon Sep 17 00:00:00 2001
From: CPunisher <1343316114@qq.com>
Date: Mon, 9 Dec 2024 10:38:27 +0800
Subject: [PATCH] fix(es/resolver): Fix wrong syntax context of vars with the
 same names as catch params (#9786)

**Description:**

When hoisting variables, the names of catch params are saved in
`catch_param_decls` permanently in the process. So the following code
skips resolving the variables with the same names.

https://github.com/swc-project/swc/blob/e6fc5327b1a309eae840fe1ec3a2367adab37430/crates/swc_ecma_transforms_base/src/resolver/mod.rs#L1558

I think this is introduced in
https://github.com/swc-project/swc/pull/4574. I'm not sure why do that
because I didn't find related test cases.

**Related issue:**

 - Closes https://github.com/swc-project/swc/issues/9785
---
 .changeset/two-terms-invite.md                     |  6 ++++++
 .../tests/fixture/issues/9785/input.js             | 14 ++++++++++++++
 .../tests/fixture/issues/9785/output.js            |  9 +++++++++
 .../swc_ecma_transforms_base/src/resolver/mod.rs   |  4 ++--
 4 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/two-terms-invite.md
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/9785/input.js
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/9785/output.js

diff --git a/.changeset/two-terms-invite.md b/.changeset/two-terms-invite.md
new file mode 100644
index 000000000000..061780463a7e
--- /dev/null
+++ b/.changeset/two-terms-invite.md
@@ -0,0 +1,6 @@
+---
+swc_core: patch
+swc_ecma_transforms_base: patch
+---
+
+fix(es/transformation): Fix wrong syntax context of variables with the same names as catch params
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/9785/input.js b/crates/swc_ecma_minifier/tests/fixture/issues/9785/input.js
new file mode 100644
index 000000000000..477730c6991a
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/9785/input.js
@@ -0,0 +1,14 @@
+function dist_index_es_P(e) {
+    try {
+        t = JSON.stringify(e);
+    } catch (r) {
+        t = String(e);
+    }
+    for (var r = 0, o = 0; o < t.length; o++) {
+        r += 1;
+    }
+    console.log(r);
+    return r;
+}
+
+dist_index_es_P("aa");
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/9785/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/9785/output.js
new file mode 100644
index 000000000000..3d2bb22a9099
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/9785/output.js
@@ -0,0 +1,9 @@
+!function(e) {
+    try {
+        t = JSON.stringify("aa");
+    } catch (r) {
+        t = String("aa");
+    }
+    for(var r = 0, o = 0; o < t.length; o++)r += 1;
+    console.log(r);
+}(0);
diff --git a/crates/swc_ecma_transforms_base/src/resolver/mod.rs b/crates/swc_ecma_transforms_base/src/resolver/mod.rs
index 0c71e668d3b9..30cd3fc2212f 100644
--- a/crates/swc_ecma_transforms_base/src/resolver/mod.rs
+++ b/crates/swc_ecma_transforms_base/src/resolver/mod.rs
@@ -1627,14 +1627,14 @@ impl VisitMut for Hoister<'_, '_> {
 
         let params: Vec<Id> = find_pat_ids(&c.param);
 
+        let orig = self.catch_param_decls.clone();
+
         self.catch_param_decls
             .extend(params.into_iter().map(|v| v.0));
 
         self.in_catch_body = true;
         c.body.visit_mut_with(self);
 
-        let orig = self.catch_param_decls.clone();
-
         // let mut excluded = find_ids::<_, Id>(&c.body);
 
         // excluded.retain(|id| {