diff --git a/crates/macros/src/function.rs b/crates/macros/src/function.rs
index 477d6fb493..4600e34409 100644
--- a/crates/macros/src/function.rs
+++ b/crates/macros/src/function.rs
@@ -343,18 +343,12 @@ impl Arg {
             }
             Type::Reference(ref_) => {
                 // Returning references is invalid, so let's just create our arg
-
-                // Change any `&mut T` into `&T` and set the `as_ref` attribute on the Arg
-                // to marked it as a "passed by ref" PHP argument.
-                let mut ref_ = ref_.clone();
-                let is_mutable_ref = ref_.mutability.is_some();
-                ref_.mutability = None;
                 Some(Arg::new(
                     name,
                     ref_.to_token_stream().to_string(),
                     false,
                     default,
-                    is_mutable_ref,
+                    ref_.mutability.is_some(),
                 ))
             }
             _ => None,
diff --git a/guide/src/types/bool.md b/guide/src/types/bool.md
index 1974ff305a..498b40ec39 100644
--- a/guide/src/types/bool.md
+++ b/guide/src/types/bool.md
@@ -45,3 +45,17 @@ pub fn test_bool(input: bool) -> String {
 var_dump(test_bool(true)); // string(4) "Yes!"
 var_dump(test_bool(false)); // string(3) "No!"
 ```
+
+## Rust example, taking by reference
+
+```rust,no_run
+# #![cfg_attr(windows, feature(abi_vectorcall))]
+# extern crate ext_php_rs;
+# use ext_php_rs::prelude::*;
+# use ext_php_rs::types;
+#[php_function]
+pub fn test_bool(input: &mut types::Zval) {
+    input.reference_mut().unwrap().set_bool(false);
+}
+# fn main() {}
+```