fix(minifier): avoid inlining single use variables when the name needs to be preserved

crates/oxc_minifier/src/ctx.rs

@@ -265,4 +265,17 @@ impl<'a> Ctx<'a, '_> {
             })
             .unwrap_or_default()
     }
+
+    /// Whether the assignment expression needs to be kept to preserve the name
+    pub fn is_expression_whose_name_needs_to_be_kept(&self, expr: &Expression) -> bool {
+        let options = &self.options().keep_names;
+        if !options.class && !options.function {
+            return false;
+        }
+        if !expr.is_anonymous_function_definition() {
+            return false;
+        }
+        let is_class = matches!(expr.without_parentheses(), Expression::ClassExpression(_));
+        (options.class && is_class) || (options.function && !is_class)
+    }
 }

crates/oxc_minifier/src/peephole/minimize_statements.rs

@@ -1053,6 +1053,9 @@ impl<'a> PeepholeOptimizations {
             let BindingPatternKind::BindingIdentifier(prev_decl_id) = &prev_decl.id.kind else {
                 return true;
             };
+            if ctx.is_expression_whose_name_needs_to_be_kept(prev_decl_init) {
+                return true;
+            }
             let Some(symbol_value) =
                 ctx.state.symbol_values.get_symbol_value(prev_decl_id.symbol_id())
             else {

crates/oxc_minifier/tests/peephole/inline_single_use_variable.rs

@@ -1,6 +1,7 @@
+use oxc_minifier::{CompressOptions, CompressOptionsKeepNames};
 use oxc_span::SourceType;
 
-use crate::{default_options, test, test_options_source_type, test_same};
+use crate::{default_options, test, test_options, test_options_source_type, test_same};
 
 #[track_caller]
 fn test_script_same(source_text: &str) {
@@ -12,6 +13,15 @@ fn test_script(source_text: &str, expected: &str) {
     test_options_source_type(source_text, expected, SourceType::cjs(), &default_options());
 }
 
+#[track_caller]
+fn test_keep_names(source_text: &str, expected: &str) {
+    test_options(
+        source_text,
+        expected,
+        &CompressOptions { keep_names: CompressOptionsKeepNames::all_true(), ..default_options() },
+    );
+}
+
 #[test]
 fn test_inline_single_use_variable() {
     test_same("function wrapper(arg0, arg1) {using x = foo; return x}");
@@ -146,6 +156,43 @@ fn keep_exposed_variables() {
     test_script("{ let x = foo; x() }", "foo()");
 }
 
+#[test]
+fn keep_names() {
+    test(
+        "var x = function() {}; var y = x; console.log(y.name)",
+        "var y = function() {}; console.log(y.name)",
+    );
+    test_keep_names(
+        "var x = function() {}; var y = x; console.log(y.name)",
+        "var x = function() {}, y = x; console.log(y.name)",
+    );
+    test_keep_names(
+        "var x = (function() {}); var y = x; console.log(y.name)",
+        "var x = (function() {}), y = x; console.log(y.name)",
+    );
+    test_keep_names(
+        "var x = function foo() {}; var y = x; console.log(y.name)",
+        "var y = function foo() {}; console.log(y.name)",
+    );
+
+    test(
+        "var x = class {}; var y = x; console.log(y.name)",
+        "var y = class {}; console.log(y.name)",
+    );
+    test_keep_names(
+        "var x = class {}; var y = x; console.log(y.name)",
+        "var x = class {}, y = x; console.log(y.name)",
+    );
+    test_keep_names(
+        "var x = (class {}); var y = x; console.log(y.name)",
+        "var x = (class {}), y = x; console.log(y.name)",
+    );
+    test_keep_names(
+        "var x = class Foo {}; var y = x; console.log(y.name)",
+        "var y = class Foo {}; console.log(y.name)",
+    );
+}
+
 #[test]
 fn integration() {
     test(