error[E0623]: lifetime mismatch
   --> src/main.rs:129:29
    |
72  | fn master_function(font_path: &Path, mut sdl_master: &mut SDLMasterVars, mut gridvec_obj: &mut Gridvec, mut gridvars: &mut GridMasterVars, mut iface: &mut Interface) -> Result<(), String> {
    |                                                                                           ------------
    |                                                                                           |
    |                                                                                           these two types are declared with different lifetimes...
...
129 |     change_gridunit_texture(&mut gridvec_obj, &mut sdl_master, 2, 2, Color::RGBA(255, 0, 0, 255));
    |                             ^^^^^^^^^^^^^^^^ ...but data from `gridvec_obj` flows into `gridvec_obj` here