diff --git a/crates/libs/bindgen/src/standalone.rs b/crates/libs/bindgen/src/standalone.rs
index c81d2d4b45..63e362e84e 100644
--- a/crates/libs/bindgen/src/standalone.rs
+++ b/crates/libs/bindgen/src/standalone.rs
@@ -19,7 +19,7 @@ pub fn standalone(names: &[&str]) -> String {
 
     let mut type_names = BTreeSet::new();
     let mut core_types = BTreeSet::new();
-    let mut enums = BTreeMap::new();
+    let mut enums = BTreeSet::new();
 
     for name in names {
         let type_name = TypeName::parse(name);
@@ -95,7 +95,7 @@ pub fn standalone(names: &[&str]) -> String {
                             found = true;
                             let enum_name = gen.reader.type_def_type_name(def);
                             type_names.insert(enum_name);
-                            enums.insert(enum_name, type_name.name);
+                            enums.insert((enum_name, type_name.name));
                         }
                     }
                 }
diff --git a/crates/tests/standalone/build.rs b/crates/tests/standalone/build.rs
index 1780bfb854..d40ac38450 100644
--- a/crates/tests/standalone/build.rs
+++ b/crates/tests/standalone/build.rs
@@ -59,7 +59,10 @@ fn main() {
 
     write(
         "src/b_enumerator.rs",
-        &["Windows.Win32.Foundation.WAIT_IO_COMPLETION"],
+        &[
+            "Windows.Win32.Foundation.WAIT_IO_COMPLETION",
+            "Windows.Win32.Foundation.WAIT_TIMEOUT",
+        ],
     );
 
     write(
diff --git a/crates/tests/standalone/src/b_enumerator.rs b/crates/tests/standalone/src/b_enumerator.rs
index 7eed5fcae5..96be6122d4 100644
--- a/crates/tests/standalone/src/b_enumerator.rs
+++ b/crates/tests/standalone/src/b_enumerator.rs
@@ -9,3 +9,4 @@
 )]
 pub type WIN32_ERROR = u32;
 pub const WAIT_IO_COMPLETION: WIN32_ERROR = 192u32;
+pub const WAIT_TIMEOUT: WIN32_ERROR = 258u32;
diff --git a/crates/tests/standalone/src/lib.rs b/crates/tests/standalone/src/lib.rs
index 995c280df8..679986d90c 100644
--- a/crates/tests/standalone/src/lib.rs
+++ b/crates/tests/standalone/src/lib.rs
@@ -97,6 +97,12 @@ fn unknown() {
     }
 }
 
+#[test]
+fn enumerator() {
+    assert_eq!(b_enumerator::WAIT_IO_COMPLETION, 192);
+    assert_eq!(b_enumerator::WAIT_TIMEOUT, 258);
+}
+
 #[test]
 fn test() {
     use b_test::*;