Fix Lua::inspect_stack callback proto

Author: khvzak

src/state.rs

@@ -875,7 +875,7 @@ impl Lua {
     /// information about the function executing at a given level.
     /// Level `0` is the current running function, whereas level `n+1` is the function that has
     /// called level `n` (except for tail calls, which do not count in the stack).
-    pub fn inspect_stack<R>(&self, level: usize, f: impl FnOnce(Debug) -> R) -> Option<R> {
+    pub fn inspect_stack<R>(&self, level: usize, f: impl FnOnce(&Debug) -> R) -> Option<R> {
         let lua = self.lock();
         unsafe {
             let mut ar = mem::zeroed::<ffi::lua_Debug>();
@@ -889,7 +889,7 @@ impl Lua {
                 return None;
             }
 
-            Some(f(Debug::new(&lua, level, &mut ar)))
+            Some(f(&Debug::new(&lua, level, &mut ar)))
         }
     }