fn try_extract_error_from_fulfill_cx<'a, 'tcx>(
ocx: &ObligationCtxt<'a, 'tcx>,
generic_param_scope: LocalDefId,
placeholder_region: Region<'tcx>,
error_region: Option<Region<'tcx>>,
) -> Option<Diag<'a>>
fn try_extract_error_from_fulfill_cx<'a, 'tcx>(
ocx: &ObligationCtxt<'a, 'tcx>,
generic_param_scope: LocalDefId,
placeholder_region: Region<'tcx>,
error_region: Option<Region<'tcx>>,
) -> Option<Diag<'a>>