It's unsafe to make almost any Lua calls when userdata destructor is running.
This can cause recursive GC run and crash.
See https://github.com/luau-lang/luau/pull/510 for some details.
The definition of lua_error in all of Lua 5.1 through 5.4 says lua_error
returns int, but the Rust definition of the same function treats it as
void (because it's known not to return). This causes link-time errors when
building for wasm targets because the wasm linker is aware of function return
types and errors out if they differ between definition and declaration.
Alex Orlenko