From 7b219a930fa34d9b55c8a9817831d90ab265ff8f Mon Sep 17 00:00:00 2001
From: Boshen <1430279+Boshen@users.noreply.github.com>
Date: Sat, 18 Jan 2025 09:04:28 +0000
Subject: [PATCH] fix(minifier): fix dce shadowed undefined (#8582)

---
 .../src/constant_evaluation/mod.rs            |  7 ++----
 .../tests/ast_passes/dead_code_elimination.rs | 23 +++++++------------
 tasks/minsize/minsize.snap                    |  4 ++--
 3 files changed, 12 insertions(+), 22 deletions(-)

diff --git a/crates/oxc_ecmascript/src/constant_evaluation/mod.rs b/crates/oxc_ecmascript/src/constant_evaluation/mod.rs
index 17fb393c33ee5..22ba2b37e9da0 100644
--- a/crates/oxc_ecmascript/src/constant_evaluation/mod.rs
+++ b/crates/oxc_ecmascript/src/constant_evaluation/mod.rs
@@ -52,7 +52,7 @@ pub trait ConstantEvaluation<'a> {
     }
 
     fn get_side_free_boolean_value(&self, expr: &Expression<'a>) -> Option<bool> {
-        let value = expr.to_boolean();
+        let value = self.get_boolean_value(expr);
         if value.is_some() && !expr.may_have_side_effects() {
             return value;
         }
@@ -124,10 +124,7 @@ pub trait ConstantEvaluation<'a> {
                     _ => None,
                 }
             }
-            expr => {
-                use crate::ToBoolean;
-                expr.to_boolean()
-            }
+            expr => expr.to_boolean(),
         }
     }
 
diff --git a/crates/oxc_minifier/tests/ast_passes/dead_code_elimination.rs b/crates/oxc_minifier/tests/ast_passes/dead_code_elimination.rs
index 595bcabc721d9..5a1e43ff6e16e 100644
--- a/crates/oxc_minifier/tests/ast_passes/dead_code_elimination.rs
+++ b/crates/oxc_minifier/tests/ast_passes/dead_code_elimination.rs
@@ -7,11 +7,13 @@ use oxc_minifier::Compressor;
 use oxc_parser::Parser;
 use oxc_span::SourceType;
 
-fn run(source_text: &str, source_type: SourceType) -> String {
+fn run(source_text: &str, source_type: SourceType, options: Option<CompressOptions>) -> String {
     let allocator = Allocator::default();
     let mut ret = Parser::new(&allocator, source_text, source_type).parse();
     let program = &mut ret.program;
-    Compressor::new(&allocator, CompressOptions::default()).dead_code_elimination(program);
+    if let Some(options) = options {
+        Compressor::new(&allocator, options).dead_code_elimination(program);
+    }
     Codegen::new().build(program).code
 }
 
@@ -22,8 +24,8 @@ fn test(source_text: &str, expected: &str) {
     let source_text = source_text.cow_replace("false", f);
 
     let source_type = SourceType::default();
-    let result = run(&source_text, source_type);
-    let expected = run(expected, source_type);
+    let result = run(&source_text, source_type, Some(CompressOptions::default()));
+    let expected = run(expected, source_type, None);
     assert_eq!(result, expected, "\nfor source\n{source_text}\nexpect\n{expected}\ngot\n{result}");
 }
 
@@ -78,22 +80,13 @@ fn dce_if_statement() {
 
     // Shadowed `undefined` as a variable should not be erased.
     // This is a rollup test.
-    test_same("function foo(undefined) { if (!undefined) { } }");
+    test_same("function foo(undefined) { if (!undefined) foo }");
 
     test("function foo() { if (undefined) { bar } }", "function foo() { }");
     test("function foo() { { bar } }", "function foo() { bar }");
 
     test("if (true) { foo; } if (true) { foo; }", "foo; foo;");
-
-    test(
-        "
-        if (true) { foo; return }
-        foo;
-        if (true) { bar; return }
-        bar;
-        ",
-        "{foo; return }",
-    );
+    test("if (true) { foo; return } foo; if (true) { bar; return } bar;", "{ foo; return }");
 
     // nested expression
     test(
diff --git a/tasks/minsize/minsize.snap b/tasks/minsize/minsize.snap
index 302461b5413ba..33dbadc624ac7 100644
--- a/tasks/minsize/minsize.snap
+++ b/tasks/minsize/minsize.snap
@@ -21,7 +21,7 @@ Original   | minified   | minified   | gzip       | gzip       | Fixture
 
 3.20 MB    | 1.01 MB    | 1.01 MB    | 332.01 kB  | 331.56 kB  | echarts.js
 
-6.69 MB    | 2.32 MB    | 2.31 MB    | 492.44 kB  | 488.28 kB  | antd.js   
+6.69 MB    | 2.31 MB    | 2.31 MB    | 492.51 kB  | 488.28 kB  | antd.js   
 
-10.95 MB   | 3.49 MB    | 3.49 MB    | 907.07 kB  | 915.50 kB  | typescript.js
+10.95 MB   | 3.49 MB    | 3.49 MB    | 907.24 kB  | 915.50 kB  | typescript.js