I found that Substrate has a limit of 64 pallets that can be added to the runtime. Adding more causes the following (very unobvious) error:

error[E0599]: the function or associated item `execute_block` exists for struct `Executive<Runtime, Block<Header<u32, BlakeTwo256>, ...>, ..., ..., ..., ...>`, but its trait bounds were not satisfied

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I'm using this runtime as a template.

Is there a way to extend this limitation?

1 Answer 1


I think you are the first one to hit that limit 😂. The compile error comes directly from Rust. Not sure how much we can do to have a nicer print.

frame-support exposes multiple features like tuples-96 which should enable support for runtimes with more pallets. In your Cargo.toml you would additionally enable frame-support/tuples-96.

  • Thanks, works perfectly after adding tuples-96 feature like this: frame-support = { default-features = false, git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.36", features = ["tuples-96"] }
    – Filk
    Feb 15, 2023 at 14:44
  • Limit has been increased on master branch: github.com/paritytech/substrate/pull/13760
    – Bruno
    Apr 7, 2023 at 11:42
  • That was done only for the kitchensink runtime - other projects will still need to change their code to avoid it. Apr 7, 2023 at 14:14
  • 1
    We have also improved the error message that's thrown by construct_runtime!: github.com/paritytech/substrate/pull/13763. It shouldn't be confusing anymore, once the tuple limit needs to be bumped - this should inform us properly from now on.
    – Lazycoder
    Apr 7, 2023 at 16:25

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