From aec5cdacc64296269d4c75f834d2a3021ca2db4b 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: Sat, 15 Oct 2022 18:11:20 +0900
Subject: [PATCH] fix(es/minifier): Preserve `this` of tagged template literals
 (#6165)

**Related issue:**

 - Closes https://github.com/swc-project/swc/issues/6146
---
 .../src/compress/optimize/mod.rs                 | 12 +++++++++++-
 .../tests/fixture/issues/6146/input.js           |  6 ++++++
 .../tests/fixture/issues/6146/output.js          |  6 ++++++
 .../tests/fixture/issues/vercel/007/output.js    |  2 +-
 .../tagged_call_with_invalid_escape_2/output.js  |  2 +-
 .../src/simplify/expr/mod.rs                     | 16 +++++++++++++++-
 6 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/6146/input.js
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/6146/output.js

diff --git a/crates/swc_ecma_minifier/src/compress/optimize/mod.rs b/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
index 9c5b8797cb59..1107fb0829fc 100644
--- a/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
+++ b/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
@@ -2263,12 +2263,19 @@ where
             .enumerate()
             .identify_last()
             .filter_map(|(last, (idx, expr))| {
+                #[cfg(feature = "debug")]
+                let _span =
+                    tracing::span!(tracing::Level::ERROR, "seq_expr_with_children").entered();
+
                 expr.visit_mut_with(&mut *self.with_ctx(ctx));
                 let is_injected_zero = match &**expr {
                     Expr::Lit(Lit::Num(v)) => v.span.is_dummy(),
                     _ => false,
                 };
 
+                #[cfg(feature = "debug")]
+                let _span = tracing::span!(tracing::Level::ERROR, "seq_expr").entered();
+
                 let can_remove = !last
                     && (idx != 0
                         || !is_injected_zero
@@ -2580,7 +2587,10 @@ where
     /// We don't optimize [Tpl] contained in [TaggedTpl].
     #[cfg_attr(feature = "debug", tracing::instrument(skip_all))]
     fn visit_mut_tagged_tpl(&mut self, n: &mut TaggedTpl) {
-        n.tag.visit_mut_with(self);
+        n.tag.visit_mut_with(&mut *self.with_ctx(Ctx {
+            is_this_aware_callee: true,
+            ..self.ctx
+        }));
 
         n.tpl.exprs.visit_mut_with(self);
     }
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/6146/input.js b/crates/swc_ecma_minifier/tests/fixture/issues/6146/input.js
new file mode 100644
index 000000000000..0d795027e77e
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/6146/input.js
@@ -0,0 +1,6 @@
+let o = {
+    f() {
+        assert.ok(this !== o);
+    }
+};
+(1, o.f)``;
\ No newline at end of file
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/6146/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/6146/output.js
new file mode 100644
index 000000000000..4dc21d51f806
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/6146/output.js
@@ -0,0 +1,6 @@
+let o = {
+    f () {
+        assert.ok(this !== o);
+    }
+};
+(0, o.f)``;
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/vercel/007/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/vercel/007/output.js
index 446e71b9e6d9..e5c2190d9753 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/vercel/007/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/vercel/007/output.js
@@ -9,7 +9,7 @@ import _JSXStyle from "styled-jsx/style";
                 top ? "column" : "column-reverse"
             ]
         ]
-    ]), _JSXStyle.dynamic([
+    ]), Sidebar, _JSXStyle.dynamic([
         [
             "4507deac72c40d6c",
             [
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/template_string/tagged_call_with_invalid_escape_2/output.js b/crates/swc_ecma_minifier/tests/terser/compress/template_string/tagged_call_with_invalid_escape_2/output.js
index 0e7fd3a3442c..1211727ddec4 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/template_string/tagged_call_with_invalid_escape_2/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/template_string/tagged_call_with_invalid_escape_2/output.js
@@ -1,3 +1,3 @@
 console.log(({
     y: ()=>String.raw
-}).y()`\4321\u\x`), console.log(String.raw`\4321\u\x`);
+}).y()`\4321\u\x`), console.log((0, String.raw)`\4321\u\x`);
diff --git a/crates/swc_ecma_transforms_optimization/src/simplify/expr/mod.rs b/crates/swc_ecma_transforms_optimization/src/simplify/expr/mod.rs
index 991a16603612..d77fe755fba6 100644
--- a/crates/swc_ecma_transforms_optimization/src/simplify/expr/mod.rs
+++ b/crates/swc_ecma_transforms_optimization/src/simplify/expr/mod.rs
@@ -1504,7 +1504,9 @@ impl VisitMut for SimplifyExpr {
                     }
                 }
 
-                Expr::Lit(..) | Expr::Ident(..) if self.in_callee => {
+                Expr::Lit(..) | Expr::Ident(..)
+                    if self.in_callee && !expr.may_have_side_effects(&self.expr_ctx) =>
+                {
                     if exprs.is_empty() {
                         self.changed = true;
 
@@ -1584,6 +1586,18 @@ impl VisitMut for SimplifyExpr {
         self.is_modifying = old;
     }
 
+    fn visit_mut_tagged_tpl(&mut self, n: &mut TaggedTpl) {
+        let old = self.in_callee;
+        self.in_callee = true;
+
+        n.tag.visit_mut_with(self);
+
+        self.in_callee = false;
+        n.tpl.visit_mut_with(self);
+
+        self.in_callee = old;
+    }
+
     fn visit_mut_with_stmt(&mut self, n: &mut WithStmt) {
         n.obj.visit_mut_with(self);
     }