mlua_derive: Fix #[lua(meta, field)] case

mlua_derive/src/userdata/userdata_impl.rs

@@ -356,7 +356,7 @@ pub fn userdata_impl(attr: TokenStream, item: TokenStream) -> TokenStream {
                     let lua_name = lua_attr.name(fn_name);
                     if lua_attr.meta {
                         let tokens = quote! {
-                            registry.add_meta_field(#lua_name, #type_path::#fn_name);
+                            registry.add_meta_field(#lua_name, #type_path::#fn_name());
                         };
                         registration_calls.push(with_cfg(tokens, &method.attrs));
                     } else {

tests/userdata_macro.rs

@@ -79,6 +79,11 @@ impl Rectangle {
         }
     }
 
+    #[lua(meta, field, name = "__answer")]
+    fn answer() -> u32 {
+        42
+    }
+
     #[lua(skip)]
     #[allow(unused)]
     fn helper() -> u32 {
@@ -124,7 +129,7 @@ impl Rectangle {
 }
 
 fn make_lua() -> Lua {
-    let lua = Lua::new();
+    let lua = unsafe { Lua::unsafe_new() };
     lua.globals()
         .set("Rectangle", lua.create_proxy::<Rectangle>().unwrap())
         .unwrap();
@@ -193,6 +198,12 @@ fn test_rectangle() {
         assert(other.length == 7, "other length should be 7 after transfer")
         assert(other:double_length() == 14, "double_length should be 14")
 
+        -- meta field
+        if _VERSION:match("Lua ") then
+            local mt = debug.getmetatable(rect)
+            assert(mt.__answer == 42, "__answer meta field should be 42")
+        end
+
         assert(rect.lua_version == _VERSION, "lua_version should match Lua's _VERSION")
 
         -- Consuming method