Macro rustc_hir_typeck::expr_use_visitor::return_if_err

macro_rules! return_if_err {
    ($inp: expr) => { ... };
}

If the MC results in an error, it’s because the type check failed (or will fail, when the error is uncovered and reported during writeback). In this case, we just ignore this part of the code.

Note that this macro appears similar to try!(), but, unlike try!(), it does not propagate the error.