Assertion `(op.access_type == 0)' failed

[ax0]

Aim

Try to generate a proof for this code.

Expected Behavior

A proof should be generated.

Bug

We get the following error:

nargo: /build/cpp/src/barretenberg/dsl/acir_format/block_constraint.cpp:41: void acir_format::create_block_constraints(acir_format::Composer &, const acir_format::BlockConstraint, bool): Assertion `(op.access_type == 0)' failed.

To Reproduce

1. Clone this repo.
2. Navigate to tests/depth_8.
3. Run nargo prove.

Installation Method

Compiled from source

Nargo Version

nargo 0.6.0 (git version hash: 242f07b, is dirty: false)

Additional Context

No response

Would you like to submit a PR for this Issue?

No

Support Needs

No response

[Savio-Sou]

Copying Ahmad's extra context here:

Here's a slightly simpler example (assuming you include my repo as a dependency):

use dep::trie;
use dep::trie::{get_fixed32, key_as_nibbles, KEY_LENGTH, NIBBLE_LENGTH, TrieProof32};

global N = 2;

fn main(root_hash: pub [u8; 32], trie_proof: trie::TrieProof32<100>) {
    let _r = root_hash;
    
    let key = trie_proof.key;
   
    let key_nibbles: [u4; NIBBLE_LENGTH] = key_as_nibbles(key);
    
    let mut key_offset = 0;

    let path = trie_proof.proof; // Proof path

    let depth = trie_proof.depth; // Depth of proof path

    for i in 0..N
    {
	    if (i as u8) < (depth as u8)
	    {
 	        let _lookup = get_fixed32(key_nibbles, key_offset, path); // Follow node
	    }
    }
}

The error goes away if N = 1. (get_fixed32 is called in one_level and the error does not occur there.)