Function rustc_typeck::check::wfcheck::check_type_defn

fn check_type_defn<'tcx, F>(
    tcx: TyCtxt<'tcx>, 
    item: &Item<'tcx>, 
    all_sized: bool, 
    lookup_fields: F
) where
    F: for<'fcx> FnMut(&FnCtxt<'fcx, 'tcx>) -> Vec<AdtVariant<'tcx>>, 

In a type definition, we check that to ensure that the types of the fields are well-formed.