Function SCIPtightenExprIntervalNonlinear 

pub unsafe extern "C" fn SCIPtightenExprIntervalNonlinear(
    scip: *mut SCIP,
    expr: *mut SCIP_EXPR,
    newbounds: SCIP_INTERVAL,
    cutoff: *mut c_uint,
    ntightenings: *mut c_int,
) -> SCIP_RETCODE

informs the expression about new bounds that can be used for reverse-propagation and to tighten bounds of corresponding (auxiliary) variable (if any)

@attention this function should only be called during domain propagation in cons_nonlinear