Binding#local_variable_get

static VALUE
bind_local_variable_get(VALUE bindval, VALUE sym)
{
    ID lid = check_local_id(bindval, &sym);
    const rb_binding_t *bind;
    const VALUE *ptr;
    const rb_env_t *env;

    if (!lid) goto undefined;
    if (rb_numparam_id_p(lid)) {
        rb_name_err_raise("numbered parameter '%1$s' is not a local variable",
                          bindval, ID2SYM(lid));
    }

    GetBindingPtr(bindval, bind);

    env = VM_ENV_ENVVAL_PTR(vm_block_ep(&bind->block));
    if ((ptr = get_local_variable_ptr(&env, lid, TRUE)) != NULL) {
        return *ptr;
    }

    sym = ID2SYM(lid);
  undefined:
    rb_name_err_raise("local variable '%1$s' is not defined for %2$s",
                      bindval, sym);
    UNREACHABLE_RETURN(Qundef);
}