solana token program 0xc Invalid Instruction

Question

I have recently begun getting the below error when running the createMint instruction from @solana/spl-token. To my knowledge, I have not changed any code or dependencies that would affect this.

Example Code

import { PublicKey, Connection, Keypair } from "@solana/web3.js";
import * as spl from "@solana/spl-token";

export async function generateMint(
  // I have confirmed that the authority exists and has sufficient funds (1 SOL)
  authority: Keypair,
  connection: Connection
): Promise<Keypair> {
  const mint: Keypair = Keypair.generate();
  try {
    await spl.createMint(
      connection,
      authority,
      authority.publicKey,
      authority.publicKey,
      9,
      mint
    );

  } catch (e) {
    console.trace(e)
    throw e
  }

  return mint;
}

Error

Trace: SendTransactionError: failed to send transaction: Transaction simulation failed: Error processing Instruction 1: custom program error: 0xc
    at Connection.sendEncodedTransaction (/path/to/node_modules/@solana/web3.js/src/connection.ts:5054:13)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at Connection.sendRawTransaction (/path/to/node_modules/@solana/web3.js/src/connection.ts:5013:20)
    at Connection.sendTransaction (/path/to/node_modules/@solana/web3.js/src/connection.ts:5001:12)
    at sendAndConfirmTransaction (/path/to/node_modules/@solana/web3.js/src/utils/send-and-confirm-transaction.ts:31:21) {
  logs: [
    'Program 11111111111111111111111111111111 invoke [1]',
    'Program 11111111111111111111111111111111 success',
    'Program TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA invoke [1]',
    'Program log: Error: Invalid instruction',
    'Program TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA consumed 796 of 1400000 compute units',
    'Program TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA failed: custom program error: 0xc'
  ]
}

Context

• OS Ubuntu 20.04.4 LTS (WSL 2)
• @project-serum/anchor: 0.25.0
• @solana/spl-token: 0.3.5
• invoking command: anchor test (== yarn run ts-mocha -p ./tsconfig.json -t 1000000 tests/**/*.ts)

Answer 1

Downgrading @solana/spl-token to 0.2.0 worked. I guess anchor is not up to date with solana...?