diff --git a/src/function.rs b/src/function.rs
index 57e5951..37b33fa 100644
--- a/src/function.rs
+++ b/src/function.rs
@@ -509,10 +509,10 @@ impl Function {
     }
 }
 
-pub(crate) struct WrappedFunction(pub(crate) Callback);
+struct WrappedFunction(pub(crate) Callback);
 
 #[cfg(feature = "async")]
-pub(crate) struct WrappedAsyncFunction(pub(crate) AsyncCallback);
+struct WrappedAsyncFunction(pub(crate) AsyncCallback);
 
 impl Function {
     /// Wraps a Rust function or closure, returning an opaque type that implements [`IntoLua`]
diff --git a/src/string.rs b/src/string.rs
index 47af717..38fb885 100644
--- a/src/string.rs
+++ b/src/string.rs
@@ -368,7 +368,7 @@ impl<'a> IntoIterator for BorrowedBytes<'a> {
     }
 }
 
-pub(crate) struct WrappedString<T: AsRef<[u8]>>(T);
+struct WrappedString<T: AsRef<[u8]>>(T);
 
 impl String {
     /// Wraps bytes, returning an opaque type that implements [`IntoLua`] trait.
diff --git a/src/userdata.rs b/src/userdata.rs
index 7db8896..83c5efc 100644
--- a/src/userdata.rs
+++ b/src/userdata.rs
@@ -1073,7 +1073,7 @@ impl Serialize for AnyUserData {
     }
 }
 
-pub(crate) struct WrappedUserdata<F: FnOnce(&Lua) -> Result<AnyUserData>>(F);
+struct WrappedUserdata<F: FnOnce(&Lua) -> Result<AnyUserData>>(F);
 
 impl AnyUserData {
     /// Wraps any Rust type, returning an opaque type that implements [`IntoLua`] trait.