Minor Lua 5.2 fixes

Author: khvzak

mlua-sys/src/lua52/compat.rs

@@ -125,7 +125,7 @@ pub unsafe fn lua_rawget(L: *mut lua_State, idx: c_int) -> c_int {
 
 #[inline(always)]
 pub unsafe fn lua_rawgeti(L: *mut lua_State, idx: c_int, n: lua_Integer) -> c_int {
-    let n = n.try_into().expect("cannot convert index to lua_Integer");
+    let n = n.try_into().expect("cannot convert index to c_int");
     lua_rawgeti_(L, idx, n);
     lua_type(L, -1)
 }
@@ -153,7 +153,7 @@ pub unsafe fn lua_seti(L: *mut lua_State, mut idx: c_int, n: lua_Integer) {
 
 #[inline(always)]
 pub unsafe fn lua_rawseti(L: *mut lua_State, idx: c_int, n: lua_Integer) {
-    let n = n.try_into().expect("cannot convert index from lua_Integer");
+    let n = n.try_into().expect("cannot convert index to c_int");
     lua_rawseti_(L, idx, n)
 }
 

mlua-sys/src/lua52/lauxlib.rs

@@ -166,8 +166,6 @@ pub unsafe fn luaL_getmetatable(L: *mut lua_State, n: *const c_char) {
     lua::lua_getfield_(L, lua::LUA_REGISTRYINDEX, n);
 }
 
-// luaL_opt would be implemented here but it is undocumented, so it's omitted
-
 #[inline(always)]
 pub unsafe fn luaL_loadbuffer(L: *mut lua_State, s: *const c_char, sz: usize, n: *const c_char) -> c_int {
     luaL_loadbufferx(L, s, sz, n, ptr::null())