execute_block, initialize_block, apply_extrinsic, finalize_block, offchain_worker exists for struct `Executive` but its trait bound were not satisfied

Question

I developed substrate parachain with custom pallets. Actually I wanna add OCW functionality to one of my pallets. After I updated runtime code and added CreateSignedTransaction implementation I tried to build my code, but got this errors:

the function or associated item `execute_block` exists for struct `Executive<Runtime, Block<Header<u32, BlakeTwo256>, UncheckedExtrinsic<..., ..., ..., ...>>, ..., ..., ...>`, but its trait bounds were not satisfied

And same errors for initialize_block, apply_extrinsic... Also got this:

the trait bound `sp_runtime::generic::UncheckedExtrinsic<MultiAddress<sp_runtime::AccountId32, u32>, RuntimeCall, MultiSignature, (CheckNonZeroSender<Runtime>, CheckSpecVersion<Runtime>, CheckTxVersion<Runtime>, CheckGenesis<Runtime>, CheckEra<Runtime>, CheckNonce<Runtime>, CheckWeight<Runtime>, ChargeTransactionPayment<Runtime>)>: Checkable<ChainContext<Runtime>>` is not satisfied

I used default implementation of UncheckedExtrinsic like this:

pub type UncheckedExtrinsic = generic::UncheckedExtrinsic<Address, RuntimeCall, Signature, SignedExtra>;

What could be a problem?

Thanks in advance.

Answer 1

If you look at the impl Checkable for UncheckedExtrinsic, you can see that this impl block is only present if a specific list of where clauses are met. The error you are getting is telling you that one of these where clauses are not met.

An anecdotal way that I found useful in debugging such issues is this:

• replace the entire implementation block of fn check(_) with todo!() or similar.
• Now start removing the individual where clauses one by one and try re-compiling the code
• The first time when removing a where clause makes your code compile, it means that one was the unmet one.

This should give you a good starting point to then debug further why this clause is not met.