feat!: remove mimc from stdlib (#6402)

docs/docs/noir/standard_library/cryptographic_primitives/hashes.mdx

@@ -2,9 +2,9 @@
 title: Hash methods
 description:
   Learn about the cryptographic primitives ready to use for any Noir project, including sha256,
-  blake2s, pedersen, mimc_bn254 and mimc
+  blake2s and pedersen
 keywords:
-  [cryptographic primitives, Noir project, sha256, blake2s, pedersen, mimc_bn254, mimc, hash]
+  [cryptographic primitives, Noir project, sha256, blake2s, pedersen, hash]
 sidebar_position: 0
 ---
 
@@ -131,32 +131,6 @@ example:
 
 #include_code poseidon2 test_programs/execution_success/poseidon2/src/main.nr rust
 
-## mimc_bn254 and mimc
-
-`mimc_bn254` is `mimc`, but with hardcoded parameters for the BN254 curve. You can use it by
-providing an array of Fields, and it returns a Field with the hash. You can use the `mimc` method if
-you're willing to input your own constants:
-
-```rust
-fn mimc<N>(x: Field, k: Field, constants: [Field; N], exp : Field) -> Field
-```
-
-otherwise, use the `mimc_bn254` method:
-
-```rust
-fn mimc_bn254<let N: u32>(array: [Field; N]) -> Field
-```
-
-example:
-
-```rust
-
-fn main() {
-    let x = [163, 117, 178, 149]; // some random bytes
-    let hash = std::hash::mimc::mimc_bn254(x);
-}
-```
-
 ## hash_to_field
 
 ```rust

noir_stdlib/src/hash/mod.nr

@@ -1,5 +1,4 @@
 pub mod poseidon;
-pub mod mimc;
 pub mod poseidon2;
 pub mod keccak;
 pub mod sha256;

test_programs/execution_success/6/src/main.nr

@@ -3,15 +3,9 @@
 // bytes.
 //
 // If you do not cast, it will take all the bytes from the field element!
-// Mimc input is an array of field elements
-// The function is called mimc_bn254 to emphasize its parameters are chosen for bn254 curve, it should be used only with a proving system using the same curve (e.g Plonk from Aztec)
 fn main(x: [u8; 5], result: pub [u8; 32]) {
     let mut digest = std::hash::sha256(x);
     digest[0] = 5 as u8;
     digest = std::hash::sha256(x);
     assert(digest == result);
-
-    let y = [12, 45, 78, 41];
-    let h = std::hash::mimc::mimc_bn254(y);
-    assert(h == 18226366069841799622585958305961373004333097209608110160936134895615261821931);
 }

test_programs/execution_success/merkle_insert/Prover.toml

@@ -8,4 +8,3 @@ old_hash_path = [
 new_root = "0x25e2a8ee5b85e5b546ae27832b9b53f5fae5b371e3e7f8cddda839f41669fc68"
 leaf = "0x23fe6c8f2426b793f0f156f57efbecbea52e951af761634a85e80cc1a9fb5003"
 index = "0"
-mimc_input = [12, 45, 78, 41]

test_programs/execution_success/merkle_insert/src/main.nr

@@ -1,21 +1,13 @@
-use std::hash::mimc;
-
 fn main(
     old_root: Field,
     old_leaf: Field,
     old_hash_path: [Field; 3],
     new_root: pub Field,
     leaf: Field,
     index: Field,
-    mimc_input: [Field; 4],
 ) {
     assert(old_root == std::merkle::compute_merkle_root(old_leaf, index, old_hash_path));
 
     let calculated_root = std::merkle::compute_merkle_root(leaf, index, old_hash_path);
     assert(new_root == calculated_root);
-
-    let h = mimc::mimc_bn254(mimc_input);
-    // Regression test for PR #891
-    std::println(h);
-    assert(h == 18226366069841799622585958305961373004333097209608110160936134895615261821931);
 }

test_programs/execution_success/regression_5252/src/main.nr

@@ -1,4 +1,4 @@
-use std::hash::{mimc, poseidon, poseidon2::Poseidon2};
+use std::hash::{poseidon, poseidon2::Poseidon2};
 
 global NUM_HASHES = 3;
 global HASH_LENGTH = 20;
@@ -16,9 +16,7 @@ fn main(
         let enable = enable[i];
         let to_hash = to_hash[i];
         if enable {
-            result[i] = poseidon_hash(to_hash)
-                + poseidon::bn254::sponge(to_hash)
-                + mimc::mimc_bn254(to_hash);
+            result[i] = poseidon_hash(to_hash) + poseidon::bn254::sponge(to_hash);
         }
     }
     result