From 559d1202bc9a25c06eae01c6e033a44bb31aab62 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, 11 Apr 2023 13:48:11 +0900
Subject: [PATCH] feat(es/minifier): Support `PURE` comment of seq exprs
 (#7245)

**Related issue:**

 - Closes https://github.com/swc-project/swc/issues/7241.
---
 .../fixture/issues-7xxx/7241/input/.swcrc     | 18 +++++++++++
 .../fixture/issues-7xxx/7241/input/index.js   | 18 +++++++++++
 .../fixture/issues-7xxx/7241/output/index.js  |  4 +++
 crates/swc_ecma_minifier/src/metadata/mod.rs  | 32 ++++++++++++-------
 .../tests/fixture/issues/7241/input.js        | 18 +++++++++++
 .../tests/fixture/issues/7241/output.js       |  4 +++
 6 files changed, 83 insertions(+), 11 deletions(-)
 create mode 100644 crates/swc/tests/fixture/issues-7xxx/7241/input/.swcrc
 create mode 100644 crates/swc/tests/fixture/issues-7xxx/7241/input/index.js
 create mode 100644 crates/swc/tests/fixture/issues-7xxx/7241/output/index.js
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/7241/input.js
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/7241/output.js

diff --git a/crates/swc/tests/fixture/issues-7xxx/7241/input/.swcrc b/crates/swc/tests/fixture/issues-7xxx/7241/input/.swcrc
new file mode 100644
index 000000000000..ee83abeb4327
--- /dev/null
+++ b/crates/swc/tests/fixture/issues-7xxx/7241/input/.swcrc
@@ -0,0 +1,18 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "ecmascript",
+            "jsx": false
+        },
+        "target": "es2022",
+        "loose": false,
+        "minify": {
+            "compress": true,
+            "mangle": true
+        }
+    },
+    "module": {
+        "type": "es6"
+    },
+    "isModule": true
+}
\ No newline at end of file
diff --git a/crates/swc/tests/fixture/issues-7xxx/7241/input/index.js b/crates/swc/tests/fixture/issues-7xxx/7241/input/index.js
new file mode 100644
index 000000000000..f8b404b93152
--- /dev/null
+++ b/crates/swc/tests/fixture/issues-7xxx/7241/input/index.js
@@ -0,0 +1,18 @@
+(function () {
+    function forwardRef() {
+        return something();
+    }
+
+    function Test() {
+        return 'Test';
+    }
+    const _Test = /*#__PURE__*/ (0, forwardRef)(Test);
+    function Other() {
+        return 'Other';
+    }
+    const _Other = /*#__PURE__*/ (0, forwardRef)(Other);
+
+
+    console.log((0, _Test));
+
+})();
\ No newline at end of file
diff --git a/crates/swc/tests/fixture/issues-7xxx/7241/output/index.js b/crates/swc/tests/fixture/issues-7xxx/7241/output/index.js
new file mode 100644
index 000000000000..25ef426dc600
--- /dev/null
+++ b/crates/swc/tests/fixture/issues-7xxx/7241/output/index.js
@@ -0,0 +1,4 @@
+!function() {
+    let o = something();
+    console.log(o);
+}();
diff --git a/crates/swc_ecma_minifier/src/metadata/mod.rs b/crates/swc_ecma_minifier/src/metadata/mod.rs
index 0ec68f5a5aa0..de4541a51125 100644
--- a/crates/swc_ecma_minifier/src/metadata/mod.rs
+++ b/crates/swc_ecma_minifier/src/metadata/mod.rs
@@ -132,7 +132,17 @@ impl VisitMut for InfoMarker<'_> {
             n.span = n.span.apply_mark(self.marks.noinline);
         }
 
-        if self.has_pure(n.span) {
+        // We check callee in some cases because we move comments
+        // See https://github.com/swc-project/swc/issues/7241
+        if self.has_pure(n.span)
+            || match &n.callee {
+                Callee::Expr(e) => match &**e {
+                    Expr::Seq(callee) => self.has_pure(callee.span),
+                    _ => false,
+                },
+                _ => false,
+            }
+        {
             n.span = n.span.apply_mark(self.marks.pure);
         } else if let Some(pure_fns) = &self.pure_funcs {
             if let Callee::Expr(e) = &n.callee {
@@ -146,14 +156,6 @@ impl VisitMut for InfoMarker<'_> {
         }
     }
 
-    fn visit_mut_new_expr(&mut self, n: &mut NewExpr) {
-        n.visit_mut_children_with(self);
-
-        if self.has_pure(n.span) {
-            n.span = n.span.apply_mark(self.marks.pure);
-        }
-    }
-
     fn visit_mut_export_default_decl(&mut self, e: &mut ExportDefaultDecl) {
         self.state.is_in_export = true;
         e.visit_mut_children_with(self);
@@ -199,7 +201,7 @@ impl VisitMut for InfoMarker<'_> {
 
     fn visit_mut_lit(&mut self, _: &mut Lit) {}
 
-    fn visit_mut_script(&mut self, n: &mut Script) {
+    fn visit_mut_module(&mut self, n: &mut Module) {
         n.visit_mut_children_with(self);
 
         if self.state.is_bundle {
@@ -210,7 +212,15 @@ impl VisitMut for InfoMarker<'_> {
         }
     }
 
-    fn visit_mut_module(&mut self, n: &mut Module) {
+    fn visit_mut_new_expr(&mut self, n: &mut NewExpr) {
+        n.visit_mut_children_with(self);
+
+        if self.has_pure(n.span) {
+            n.span = n.span.apply_mark(self.marks.pure);
+        }
+    }
+
+    fn visit_mut_script(&mut self, n: &mut Script) {
         n.visit_mut_children_with(self);
 
         if self.state.is_bundle {
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/7241/input.js b/crates/swc_ecma_minifier/tests/fixture/issues/7241/input.js
new file mode 100644
index 000000000000..f8b404b93152
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/7241/input.js
@@ -0,0 +1,18 @@
+(function () {
+    function forwardRef() {
+        return something();
+    }
+
+    function Test() {
+        return 'Test';
+    }
+    const _Test = /*#__PURE__*/ (0, forwardRef)(Test);
+    function Other() {
+        return 'Other';
+    }
+    const _Other = /*#__PURE__*/ (0, forwardRef)(Other);
+
+
+    console.log((0, _Test));
+
+})();
\ No newline at end of file
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/7241/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/7241/output.js
new file mode 100644
index 000000000000..70ee78471cef
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/7241/output.js
@@ -0,0 +1,4 @@
+!function() {
+    const _Test = something();
+    console.log(_Test);
+}();