fn equate_impl_headers<'tcx>(
infcx: &InferCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
impl1: &ImplHeader<'tcx>,
impl2: &ImplHeader<'tcx>,
) -> Option<Vec<PredicateObligation<'tcx>>>
fn equate_impl_headers<'tcx>(
infcx: &InferCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
impl1: &ImplHeader<'tcx>,
impl2: &ImplHeader<'tcx>,
) -> Option<Vec<PredicateObligation<'tcx>>>