Following the merge of https://github.com/bitcoin/bitcoin/pull/23083, we'll throw a non-fatal error at runtime if the documentation for an RPC is incorrect. This behaviour has found numerous issues over a very short period (of the PR being opened). However, this is not something that we want in production / release builds, instead, we want the ability to have it enabled in the CI and when running tests. A runtime option could be added, which controls this behaviour (disabled by default).

#### Useful skills:

- C++
- Understanding of Bitcoin Core's initialization sequence
- Understanding of Bitcoin Core's RPC interface

#### Want to work on this issue?

For guidance on contributing, please read [CONTRIBUTING.md](https://github.com/bitcoin/bitcoin/blob/master/CONTRIBUTING.md) before opening your pull request.

{
    std::vector<std::string> ret;
    using U = std::underlying_type<TxoutType>::type;
    for (U i = (U)TxoutType::NONSTANDARD; i <= (U)TxoutType::WITNESS_UNKNOWN; ++i) {
        ret.emplace_back(GetTxnOutputType(static_cast<TxoutType>(i)));
    }
    return Join(ret, ", ");
}
void RPCTypeCheck(const UniValue& params,
                  const std::list<UniValueType>& typesExpected,
                  bool fAllowNull)
{
    unsigned int i = 0;
    for (const UniValueType& t : typesExpected) {
        if (params.size() <= i)
            break;
        const UniValue& v = params[i];
        if (!(fAllowNull && v.isNull())) {
            RPCTypeCheckArgument(v, t);
        }
        i++;
    }
}
void RPCTypeCheckArgument(const UniValue& value, const UniValueType& typeExpected)
{
    if (!typeExpected.typeAny && value.type() != typeExpected.type) {
        throw JSONRPCError(RPC_TYPE_ERROR, strprintf("Expected type %s, got %s", uvTypeName(typeExpected.type), uvTypeName(value.type())));
    }
}
void RPCTypeCheckObj(const UniValue& o,