fn try_extract_error_from_region_constraints<'tcx>(
    infcx: &InferCtxt<'tcx>,
    placeholder_region: Region<'tcx>,
    error_region: Option<Region<'tcx>>,
    region_constraints: &RegionConstraintData<'tcx>,
    region_var_origin: impl FnMut(RegionVid) -> RegionVariableOrigin,
    universe_of_region: impl FnMut(RegionVid) -> UniverseIndex
) -> Option<Diag<'tcx>>