Remove FromLua impl for UserData+Clone

examples/guided_tour.rs

@@ -1,7 +1,9 @@
 use std::f32;
 use std::iter::FromIterator;
 
-use mlua::{chunk, Function, Lua, MetaMethod, Result, UserData, UserDataMethods, Variadic};
+use mlua::{
+    chunk, FromLua, Function, Lua, MetaMethod, Result, UserData, UserDataMethods, Value, Variadic,
+};
 
 fn main() -> Result<()> {
     // You can create a new Lua state with `Lua::new()`. This loads the default Lua std library
@@ -151,6 +153,16 @@ fn main() -> Result<()> {
     #[derive(Copy, Clone)]
     struct Vec2(f32, f32);
 
+    // We can implement `FromLua` trait for our `Vec2` to return a copy
+    impl<'lua> FromLua<'lua> for Vec2 {
+        fn from_lua(value: Value<'lua>, _: &'lua Lua) -> Result<Self> {
+            match value {
+                Value::UserData(ud) => Ok(*ud.borrow::<Self>()?),
+                _ => unreachable!(),
+            }
+        }
+    }
+
     impl UserData for Vec2 {
         fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
             methods.add_method("magnitude", |_, vec, ()| {

src/conversion.rs

@@ -194,21 +194,6 @@ impl<'lua, T: 'static + MaybeSend + UserData> IntoLua<'lua> for T {
     }
 }
 
-// TODO: Remove
-impl<'lua, T: 'static + UserData + Clone> FromLua<'lua> for T {
-    #[inline]
-    fn from_lua(value: Value<'lua>, _: &'lua Lua) -> Result<T> {
-        match value {
-            Value::UserData(ud) => Ok(ud.borrow::<T>()?.clone()),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: "userdata",
-                message: None,
-            }),
-        }
-    }
-}
-
 impl<'lua> IntoLua<'lua> for Error {
     #[inline]
     fn into_lua(self, _: &'lua Lua) -> Result<Value<'lua>> {

tests/userdata.rs

@@ -12,8 +12,8 @@ use std::{cell::RefCell, rc::Rc};
 use std::sync::atomic::{AtomicI64, Ordering};
 
 use mlua::{
-    AnyUserData, Error, ExternalError, Function, Lua, MetaMethod, Nil, Result, String, UserData,
-    UserDataFields, UserDataMethods, Value,
+    AnyUserData, Error, ExternalError, FromLua, Function, Lua, MetaMethod, Nil, Result, String,
+    UserData, UserDataFields, UserDataMethods, Value,
 };
 
 #[test]
@@ -95,6 +95,15 @@ fn test_metamethods() -> Result<()> {
     #[derive(Copy, Clone)]
     struct MyUserData(i64);
 
+    impl<'lua> FromLua<'lua> for MyUserData {
+        fn from_lua(value: Value<'lua>, _: &'lua Lua) -> Result<Self> {
+            match value {
+                Value::UserData(ud) => Ok(ud.borrow::<Self>()?.clone()),
+                _ => unreachable!(),
+            }
+        }
+    }
+
     impl UserData for MyUserData {
         fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
             methods.add_method("get", |_, data, ()| Ok(data.0));