undefined_loop_level.cpp
#include "Halide.h"
#include <stdio.h>
using namespace Halide;
int main(int argc, char **argv) {
LoopLevel undefined;
Var x;
Func f, g;
f(x) = x;
g(x) = f(x);
f.compute_at(undefined);
g.compute_root();
// Trying to lower/realize with an undefined LoopLevel should be fatal
Buffer<int> result = g.realize(1);
printf("I should not have reached here\n");
return 0;
}