From 9be29af9d45cb176fa3b3cb10da899c50867cb3d Mon Sep 17 00:00:00 2001
From: Boshen <1430279+Boshen@users.noreply.github.com>
Date: Tue, 6 Aug 2024 04:58:39 +0000
Subject: [PATCH] fix(minifier): temporarily fix shadowed `undefined` variable
 (#4678)

---
 crates/oxc_minifier/src/ast_util.rs               | 15 ++++++---------
 crates/oxc_minifier/tests/oxc/remove_dead_code.rs |  9 +++++----
 tasks/coverage/minifier_test262.snap              |  6 +++++-
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/crates/oxc_minifier/src/ast_util.rs b/crates/oxc_minifier/src/ast_util.rs
index ba10b60412282..2e1eab349e3c6 100644
--- a/crates/oxc_minifier/src/ast_util.rs
+++ b/crates/oxc_minifier/src/ast_util.rs
@@ -484,15 +484,12 @@ pub fn get_boolean_value(expr: &Expression) -> Option<bool> {
                 .and_then(|quasi| quasi.value.cooked.as_ref())
                 .map(|cooked| !cooked.is_empty())
         }
-        Expression::Identifier(ident) => {
-            if expr.is_undefined() || ident.name == "NaN" {
-                Some(false)
-            } else if ident.name == "Infinity" {
-                Some(true)
-            } else {
-                None
-            }
-        }
+        Expression::Identifier(ident) => match ident.name.as_str() {
+            "NaN" => Some(false),
+            "Infinity" => Some(true),
+            // "undefined" if ident.reference_id.get().is_none() => Some(false),
+            _ => None,
+        },
         Expression::AssignmentExpression(assign_expr) => {
             match assign_expr.operator {
                 AssignmentOperator::LogicalAnd | AssignmentOperator::LogicalOr => None,
diff --git a/crates/oxc_minifier/tests/oxc/remove_dead_code.rs b/crates/oxc_minifier/tests/oxc/remove_dead_code.rs
index 79456fb6fc4d1..96f17019c5f17 100644
--- a/crates/oxc_minifier/tests/oxc/remove_dead_code.rs
+++ b/crates/oxc_minifier/tests/oxc/remove_dead_code.rs
@@ -70,10 +70,11 @@ fn dce_if_statement() {
     test("if ('development' === 'production') { foo } else { bar }", "{ bar }");
 
     // Shadowed `undefined` as a variable should not be erased.
-    // test(
-    // "function foo(undefined) { if (!undefined) { } }",
-    // "function foo(undefined) { if (!undefined) { } }",
-    // );
+    // This is a rollup test.
+    test(
+        "function foo(undefined) { if (!undefined) { } }",
+        "function foo(undefined) { if (!undefined) { } }",
+    );
 
     test("if (true) { foo; } if (true) { foo; }", "{ foo; } { foo; }");
 
diff --git a/tasks/coverage/minifier_test262.snap b/tasks/coverage/minifier_test262.snap
index 6f4e52f07c749..66336a0659aac 100644
--- a/tasks/coverage/minifier_test262.snap
+++ b/tasks/coverage/minifier_test262.snap
@@ -2,4 +2,8 @@ commit: a1587416
 
 minifier_test262 Summary:
 AST Parsed     : 46406/46406 (100.00%)
-Positive Passed: 46406/46406 (100.00%)
+Positive Passed: 46402/46406 (99.99%)
+Expect to Parse: "language/expressions/logical-and/S11.11.1_A3_T4.js"
+Expect to Parse: "language/expressions/logical-not/S9.2_A1_T2.js"
+Expect to Parse: "language/statements/if/S12.5_A1.1_T1.js"
+Expect to Parse: "language/statements/if/S12.5_A1.1_T2.js"