From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Samuel Attard <samuel.r.attard@gmail.com>
Date: Wed, 3 Mar 2021 15:52:46 -0800
Subject: fix: add CHECK for sandbox then_result

It fixes things, we do not know why, we should look at reverting this
patch and doing further investigation in the future.  This patch cannot
be upstreamed.

diff --git a/sandbox/linux/bpf_dsl/bpf_dsl.cc b/sandbox/linux/bpf_dsl/bpf_dsl.cc
index 6bb9ba9623e042c25fa74e64e0fa1bc32f8f5331..b7dced446865236490c8a0b3646f8e0026b95b71 100644
--- a/sandbox/linux/bpf_dsl/bpf_dsl.cc
+++ b/sandbox/linux/bpf_dsl/bpf_dsl.cc
@@ -321,6 +321,7 @@ Elser::~Elser() {
 }
 
 Elser Elser::ElseIf(BoolExpr cond, ResultExpr then_result) const {
+  CHECK(then_result);
   return Elser(Cons(std::make_pair(std::move(cond), std::move(then_result)),
                     clause_list_));
 }
