# Description

Working with https://github.com/paritytech/polkadot-sdk/pull/7556 I
encountered an internal compiler error on polkadot-omni-node-lib: see
bellow or [in
CI](https://github.com/paritytech/polkadot-sdk/actions/runs/13521547633/job/37781894640).

```
error: internal compiler error: compiler/rustc_traits/src/codegen.rs:45:13: Encountered error `SignatureMismatch(SignatureMismatchData { found_trait_ref: <{closure@sp_state_machine::trie_backend_essence::TrieBackendEssence<sc_service::Arc<dyn sp_state_machine::trie_backend_essence::Storage<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>, <<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing, sp_trie::cache::LocalTrieCache<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>, sp_trie::recorder::Recorder<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>::storage::{closure#1}} as std::ops::FnOnce<(std::option::Option<&mut dyn trie_db::TrieRecorder<sp_core::H256>>, std::option::Option<&mut dyn trie_db::TrieCache<sp_trie::node_codec::NodeCodec<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>>)>>, expected_trait_ref: <{closure@sp_state_machine::trie_backend_essence::TrieBackendEssence<sc_service::Arc<dyn sp_state_machine::trie_backend_essence::Storage<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>, <<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing, sp_trie::cache::LocalTrieCache<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>, sp_trie::recorder::Recorder<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>::storage::{closure#1}} as std::ops::FnOnce<(std::option::Option<&mut dyn trie_db::TrieRecorder<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hash>>, std::option::Option<&mut dyn trie_db::TrieCache<sp_trie::node_codec::NodeCodec<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>>)>>, terr: Sorts(ExpectedFound { expected: Alias(Projection, AliasTy { args: [Alias(Projection, AliasTy { args: [Alias(Projection, AliasTy { args: [NodeSpec/#0], def_id: DefId(0:410 ~ polkadot_omni_node_lib[7cce]::common::spec::BaseNodeSpec::Block), .. })], def_id: DefId(0:507 ~ polkadot_omni_node_lib[7cce]::common::NodeBlock::BoundedHeader), .. })], def_id: DefId(229:1706 ~ sp_runtime[5da1]::traits::Header::Hash), .. }), found: sp_core::H256 }) })` selecting `<{closure@sp_state_machine::trie_backend_essence::TrieBackendEssence<sc_service::Arc<dyn sp_state_machine::trie_backend_essence::Storage<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>, <<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing, sp_trie::cache::LocalTrieCache<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>, sp_trie::recorder::Recorder<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>::storage::{closure#1}} as std::ops::FnOnce<(std::option::Option<&mut dyn trie_db::TrieRecorder<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hash>>, std::option::Option<&mut dyn trie_db::TrieCache<sp_trie::node_codec::NodeCodec<<<<NodeSpec as common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader as sp_runtime::traits::Header>::Hashing>>>)>>` during codegen
```

Trying to parse the error I found that TrieRecorder was not supposed to
work with H256:
- Expected: `&mut dyn TrieRecorder<<<<NodeSpec as
common::spec::BaseNodeSpec>::Block as common::NodeBlock>::BoundedHeader
as Header>::Hash>>`
- Found: `&mut dyn TrieRecorder<sp_core::H256>>`

The error happened because I added to
`new_full_parts_with_genesis_builder` interaction with Trie Cache which
eventually uses `TrieRecorder<H256>`. Here is the path:
- In polkadot-omni-node-lib trait BaseNodeSpec defined with Block as
`NodeBlock: BlockT<Hash = DbHash>`, where DbHash is H256.
- BaseNodeSpec calls [new_full_parts_record_import::<Self::Block, …
>](https://github.com/paritytech/polkadot-sdk/blob/75726c65/cumulus/polkadot-omni-node/lib/src/common/spec.rs#L184-L189)
and eventually it goes to
[new_full_parts_with_genesis_builder](https://github.com/paritytech/polkadot-sdk/blob/08b30246

/substrate/client/service/src/builder.rs#L195).
- In `new_full_parts_with_genesis_builder` we accessed storage,
initiating TrieRecorder with H256 what never happened before.

I believe the compiler found a mismatch checking types for TrieRecorder:
NodeBlock inherits from the trait `Block<Hash = DbHash>`, but it uses
BoundedHeader, which inherits from the trait Header with the default
Hash.

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>