// Copyright 2023 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef GRPC_SRC_CORE_LIB_PROMISE_DETAIL_SEQ_STATE_H
#define GRPC_SRC_CORE_LIB_PROMISE_DETAIL_SEQ_STATE_H

// This file is generated by tools/codegen/core/gen_seq.py

#include <grpc/support/port_platform.h>

#include <stdint.h>

#include <utility>

#include "absl/base/attributes.h"
#include "absl/strings/str_cat.h"

#include <grpc/support/log.h>

#include "src/core/lib/gprpp/construct_destruct.h"
#include "src/core/lib/gprpp/debug_location.h"
#include "src/core/lib/promise/detail/promise_factory.h"
#include "src/core/lib/promise/detail/promise_like.h"
#include "src/core/lib/promise/poll.h"
#include "src/core/lib/promise/trace.h"

// A sequence under some traits for some set of callables P, Fs.
// P should be a promise-like object that yields a value.
// Fs... should be promise-factory-like objects that take the value from the
// previous step and yield a promise. Note that most of the machinery in
// PromiseFactory exists to make it possible for those promise-factory-like
// objects to be anything that's convenient.
// Traits defines how we move from one step to the next. Traits sets up the
// wrapping and escape handling for the sequence.
// Promises return wrapped values that the trait can inspect and unwrap before
// passing them to the next element of the sequence. The trait can
// also interpret a wrapped value as an escape value, which terminates
// evaluation of the sequence immediately yielding a result. Traits for type T
// have the members:
//  * type UnwrappedType - the type after removing wrapping from T (i.e. for
//    TrySeq, T=StatusOr<U> yields UnwrappedType=U).
//  * type WrappedType - the type after adding wrapping if it doesn't already
//    exist (i.e. for TrySeq if T is not Status/StatusOr/void, then
//    WrappedType=StatusOr<T>; if T is Status then WrappedType=Status (it's
//    already wrapped!))
//  * template <typename Next> void CallFactory(Next* next_factory, T&& value) -
//    call promise factory next_factory with the result of unwrapping value, and
//    return the resulting promise.
//  * template <typename Result, typename RunNext> Poll<Result>
//    CheckResultAndRunNext(T prior, RunNext run_next) - examine the value of
//    prior, and decide to escape or continue. If escaping, return the final
//    sequence value of type Poll<Result>. If continuing, return the value of
//    run_next(std::move(prior)).
//
// A state contains the current promise, and the promise factory to turn the
// result of the current promise into the next state's promise. We play a shell
// game such that the prior state and our current promise are kept in a union,
// and the next promise factory is kept alongside in the state struct.
// Recursively this guarantees that the next functions get initialized once, and
// destroyed once, and don't need to be moved around in between, which avoids a
// potential O(n**2) loop of next factory moves had we used a variant of states
// here. The very first state does not have a prior state, and so that state has
// a partial specialization below. The final state does not have a next state;
// that state is inlined in BasicSeq since that was simpler to type.

namespace grpc_core {
namespace promise_detail {
template <template <typename> class Traits, typename P, typename... Fs>
struct SeqState;

template <template <typename> class Traits, typename P, typename F0>
struct SeqState<Traits, P, F0> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using Result = typename PromiseResultTraits1::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running0 prior;
    GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
  };
  enum class State : uint8_t { kState0, kState1 };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, DebugLocation whence) noexcept : whence(whence) {
    Construct(&prior.current_promise, std::forward<P>(p));
    Construct(&prior.next_factory, std::forward<F0>(f0));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/2", this);
        }
        auto result = prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/2 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/2", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 2/2 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1>
struct SeqState<Traits, P, F0, F1> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using Result = typename PromiseResultTraits2::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running1 prior;
    GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
  };
  enum class State : uint8_t { kState0, kState1, kState2 };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.current_promise, std::forward<P>(p));
    Construct(&prior.prior.next_factory, std::forward<F0>(f0));
    Construct(&prior.next_factory, std::forward<F1>(f1));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.next_factory);
  tail1:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail1:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/3", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/3 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/3", this);
        }
        auto result = prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/3 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/3", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 3/3 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2>
struct SeqState<Traits, P, F0, F1, F2> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using Result = typename PromiseResultTraits3::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running2 prior;
    GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
  };
  enum class State : uint8_t { kState0, kState1, kState2, kState3 };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.current_promise, std::forward<P>(p));
    Construct(&prior.prior.prior.next_factory, std::forward<F0>(f0));
    Construct(&prior.prior.next_factory, std::forward<F1>(f1));
    Construct(&prior.next_factory, std::forward<F2>(f2));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.next_factory);
  tail1:
    Destruct(&prior.prior.next_factory);
  tail2:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail2;
      case State::kState3:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail1:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail2:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/4", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/4 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/4", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/4 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/4", this);
        }
        auto result = prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/4 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/4", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 4/4 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3>
struct SeqState<Traits, P, F0, F1, F2, F3> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using Result = typename PromiseResultTraits4::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running3 prior;
    GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
  };
  enum class State : uint8_t { kState0, kState1, kState2, kState3, kState4 };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3,
           DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.prior.current_promise, std::forward<P>(p));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F0>(f0));
    Construct(&prior.prior.prior.next_factory, std::forward<F1>(f1));
    Construct(&prior.prior.next_factory, std::forward<F2>(f2));
    Construct(&prior.next_factory, std::forward<F3>(f3));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.prior.current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&prior.current_promise);
        goto tail3;
      case State::kState4:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail1:
    Destruct(&prior.prior.prior.next_factory);
  tail2:
    Destruct(&prior.prior.next_factory);
  tail3:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail2;
      case State::kState3:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail3;
      case State::kState4:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail1:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail2:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail3:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/5", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/5 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/5", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/5 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/5", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/5 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/5", this);
        }
        auto result = prior.current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/5 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/5", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 5/5 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3, typename F4>
struct SeqState<Traits, P, F0, F1, F2, F3, F4> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using NextFactory4 =
      OncePromiseFactory<typename PromiseResultTraits4::UnwrappedType, F4>;
  using Promise5 = typename NextFactory4::Promise;
  using PromiseResult5 = typename Promise5::Result;
  using PromiseResultTraits5 = Traits<PromiseResult5>;
  using Result = typename PromiseResultTraits5::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  struct Running4 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running3 prior;
      GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory4 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running4 prior;
    GPR_NO_UNIQUE_ADDRESS Promise5 current_promise;
  };
  enum class State : uint8_t {
    kState0,
    kState1,
    kState2,
    kState3,
    kState4,
    kState5
  };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3, F4&& f4,
           DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.prior.prior.current_promise,
              std::forward<P>(p));
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::forward<F0>(f0));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F1>(f1));
    Construct(&prior.prior.prior.next_factory, std::forward<F2>(f2));
    Construct(&prior.prior.next_factory, std::forward<F3>(f3));
    Construct(&prior.next_factory, std::forward<F4>(f4));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.prior.prior.current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&prior.prior.current_promise);
        goto tail3;
      case State::kState4:
        Destruct(&prior.current_promise);
        goto tail4;
      case State::kState5:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.prior.prior.next_factory);
  tail1:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail2:
    Destruct(&prior.prior.prior.next_factory);
  tail3:
    Destruct(&prior.prior.next_factory);
  tail4:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(
            &prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail2;
      case State::kState3:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail3;
      case State::kState4:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail4;
      case State::kState5:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.next_factory));
  tail1:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail2:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail3:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail4:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/6", this);
        }
        auto result = prior.prior.prior.prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/6 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/6", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/6 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/6", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/6 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/6", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/6 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/6", this);
        }
        auto result = prior.current_promise();
        PromiseResult4* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 5/6 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits4::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits4::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits4::IsOk(*p)) {
          return PromiseResultTraits4::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits4::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState5;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState5: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 6/6", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 6/6 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3, typename F4, typename F5>
struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using NextFactory4 =
      OncePromiseFactory<typename PromiseResultTraits4::UnwrappedType, F4>;
  using Promise5 = typename NextFactory4::Promise;
  using PromiseResult5 = typename Promise5::Result;
  using PromiseResultTraits5 = Traits<PromiseResult5>;
  using NextFactory5 =
      OncePromiseFactory<typename PromiseResultTraits5::UnwrappedType, F5>;
  using Promise6 = typename NextFactory5::Promise;
  using PromiseResult6 = typename Promise6::Result;
  using PromiseResultTraits6 = Traits<PromiseResult6>;
  using Result = typename PromiseResultTraits6::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  struct Running4 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running3 prior;
      GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory4 next_factory;
  };
  struct Running5 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running4 prior;
      GPR_NO_UNIQUE_ADDRESS Promise5 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory5 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running5 prior;
    GPR_NO_UNIQUE_ADDRESS Promise6 current_promise;
  };
  enum class State : uint8_t {
    kState0,
    kState1,
    kState2,
    kState3,
    kState4,
    kState5,
    kState6
  };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3, F4&& f4, F5&& f5,
           DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.prior.prior.prior.current_promise,
              std::forward<P>(p));
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F0>(f0));
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::forward<F1>(f1));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F2>(f2));
    Construct(&prior.prior.prior.next_factory, std::forward<F3>(f3));
    Construct(&prior.prior.next_factory, std::forward<F4>(f4));
    Construct(&prior.next_factory, std::forward<F5>(f5));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&prior.prior.prior.current_promise);
        goto tail3;
      case State::kState4:
        Destruct(&prior.prior.current_promise);
        goto tail4;
      case State::kState5:
        Destruct(&prior.current_promise);
        goto tail5;
      case State::kState6:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
  tail1:
    Destruct(&prior.prior.prior.prior.prior.next_factory);
  tail2:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail3:
    Destruct(&prior.prior.prior.next_factory);
  tail4:
    Destruct(&prior.prior.next_factory);
  tail5:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(
            &prior.prior.prior.prior.prior.prior.current_promise,
            std::move(
                other.prior.prior.prior.prior.prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(
            &prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail2;
      case State::kState3:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail3;
      case State::kState4:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail4;
      case State::kState5:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail5;
      case State::kState6:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(
        &prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.next_factory));
  tail1:
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.next_factory));
  tail2:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail3:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail4:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail5:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/7", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/7 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/7", this);
        }
        auto result = prior.prior.prior.prior.prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/7 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/7", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/7 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/7", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/7 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/7", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult4* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 5/7 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits4::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits4::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits4::IsOk(*p)) {
          return PromiseResultTraits4::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits4::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState5;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState5: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 6/7", this);
        }
        auto result = prior.current_promise();
        PromiseResult5* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 6/7 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits5::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits5::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits5::IsOk(*p)) {
          return PromiseResultTraits5::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits5::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState6;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState6: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 7/7", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 7/7 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3, typename F4, typename F5,
          typename F6>
struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using NextFactory4 =
      OncePromiseFactory<typename PromiseResultTraits4::UnwrappedType, F4>;
  using Promise5 = typename NextFactory4::Promise;
  using PromiseResult5 = typename Promise5::Result;
  using PromiseResultTraits5 = Traits<PromiseResult5>;
  using NextFactory5 =
      OncePromiseFactory<typename PromiseResultTraits5::UnwrappedType, F5>;
  using Promise6 = typename NextFactory5::Promise;
  using PromiseResult6 = typename Promise6::Result;
  using PromiseResultTraits6 = Traits<PromiseResult6>;
  using NextFactory6 =
      OncePromiseFactory<typename PromiseResultTraits6::UnwrappedType, F6>;
  using Promise7 = typename NextFactory6::Promise;
  using PromiseResult7 = typename Promise7::Result;
  using PromiseResultTraits7 = Traits<PromiseResult7>;
  using Result = typename PromiseResultTraits7::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  struct Running4 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running3 prior;
      GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory4 next_factory;
  };
  struct Running5 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running4 prior;
      GPR_NO_UNIQUE_ADDRESS Promise5 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory5 next_factory;
  };
  struct Running6 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running5 prior;
      GPR_NO_UNIQUE_ADDRESS Promise6 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory6 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running6 prior;
    GPR_NO_UNIQUE_ADDRESS Promise7 current_promise;
  };
  enum class State : uint8_t {
    kState0,
    kState1,
    kState2,
    kState3,
    kState4,
    kState5,
    kState6,
    kState7
  };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3, F4&& f4, F5&& f5, F6&& f6,
           DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
              std::forward<P>(p));
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F0>(f0));
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F1>(f1));
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::forward<F2>(f2));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F3>(f3));
    Construct(&prior.prior.prior.next_factory, std::forward<F4>(f4));
    Construct(&prior.prior.next_factory, std::forward<F5>(f5));
    Construct(&prior.next_factory, std::forward<F6>(f6));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail3;
      case State::kState4:
        Destruct(&prior.prior.prior.current_promise);
        goto tail4;
      case State::kState5:
        Destruct(&prior.prior.current_promise);
        goto tail5;
      case State::kState6:
        Destruct(&prior.current_promise);
        goto tail6;
      case State::kState7:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail1:
    Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
  tail2:
    Destruct(&prior.prior.prior.prior.prior.next_factory);
  tail3:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail4:
    Destruct(&prior.prior.prior.next_factory);
  tail5:
    Destruct(&prior.prior.next_factory);
  tail6:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .current_promise));
        goto tail0;
      case State::kState1:
        Construct(
            &prior.prior.prior.prior.prior.prior.current_promise,
            std::move(
                other.prior.prior.prior.prior.prior.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(
            &prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.current_promise));
        goto tail2;
      case State::kState3:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail3;
      case State::kState4:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail4;
      case State::kState5:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail5;
      case State::kState6:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail6;
      case State::kState7:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(
            other.prior.prior.prior.prior.prior.prior.prior.next_factory));
  tail1:
    Construct(
        &prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.next_factory));
  tail2:
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.next_factory));
  tail3:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail4:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail5:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail6:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/8", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/8 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/8", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/8 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/8", this);
        }
        auto result = prior.prior.prior.prior.prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/8 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/8", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/8 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/8", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult4* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 5/8 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits4::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits4::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits4::IsOk(*p)) {
          return PromiseResultTraits4::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits4::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState5;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState5: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 6/8", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult5* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 6/8 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits5::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits5::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits5::IsOk(*p)) {
          return PromiseResultTraits5::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits5::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState6;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState6: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 7/8", this);
        }
        auto result = prior.current_promise();
        PromiseResult6* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 7/8 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits6::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits6::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits6::IsOk(*p)) {
          return PromiseResultTraits6::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits6::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState7;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState7: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 8/8", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 8/8 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3, typename F4, typename F5,
          typename F6, typename F7>
struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using NextFactory4 =
      OncePromiseFactory<typename PromiseResultTraits4::UnwrappedType, F4>;
  using Promise5 = typename NextFactory4::Promise;
  using PromiseResult5 = typename Promise5::Result;
  using PromiseResultTraits5 = Traits<PromiseResult5>;
  using NextFactory5 =
      OncePromiseFactory<typename PromiseResultTraits5::UnwrappedType, F5>;
  using Promise6 = typename NextFactory5::Promise;
  using PromiseResult6 = typename Promise6::Result;
  using PromiseResultTraits6 = Traits<PromiseResult6>;
  using NextFactory6 =
      OncePromiseFactory<typename PromiseResultTraits6::UnwrappedType, F6>;
  using Promise7 = typename NextFactory6::Promise;
  using PromiseResult7 = typename Promise7::Result;
  using PromiseResultTraits7 = Traits<PromiseResult7>;
  using NextFactory7 =
      OncePromiseFactory<typename PromiseResultTraits7::UnwrappedType, F7>;
  using Promise8 = typename NextFactory7::Promise;
  using PromiseResult8 = typename Promise8::Result;
  using PromiseResultTraits8 = Traits<PromiseResult8>;
  using Result = typename PromiseResultTraits8::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  struct Running4 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running3 prior;
      GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory4 next_factory;
  };
  struct Running5 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running4 prior;
      GPR_NO_UNIQUE_ADDRESS Promise5 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory5 next_factory;
  };
  struct Running6 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running5 prior;
      GPR_NO_UNIQUE_ADDRESS Promise6 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory6 next_factory;
  };
  struct Running7 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running6 prior;
      GPR_NO_UNIQUE_ADDRESS Promise7 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory7 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running7 prior;
    GPR_NO_UNIQUE_ADDRESS Promise8 current_promise;
  };
  enum class State : uint8_t {
    kState0,
    kState1,
    kState2,
    kState3,
    kState4,
    kState5,
    kState6,
    kState7,
    kState8
  };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3, F4&& f4, F5&& f5, F6&& f6,
           F7&& f7, DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
              std::forward<P>(p));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F0>(f0));
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F1>(f1));
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F2>(f2));
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::forward<F3>(f3));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F4>(f4));
    Construct(&prior.prior.prior.next_factory, std::forward<F5>(f5));
    Construct(&prior.prior.next_factory, std::forward<F6>(f6));
    Construct(&prior.next_factory, std::forward<F7>(f7));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        goto tail3;
      case State::kState4:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail4;
      case State::kState5:
        Destruct(&prior.prior.prior.current_promise);
        goto tail5;
      case State::kState6:
        Destruct(&prior.prior.current_promise);
        goto tail6;
      case State::kState7:
        Destruct(&prior.current_promise);
        goto tail7;
      case State::kState8:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail1:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail2:
    Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
  tail3:
    Destruct(&prior.prior.prior.prior.prior.next_factory);
  tail4:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail5:
    Destruct(&prior.prior.prior.next_factory);
  tail6:
    Destruct(&prior.prior.next_factory);
  tail7:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise));
        goto tail0;
      case State::kState1:
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .current_promise));
        goto tail1;
      case State::kState2:
        Construct(
            &prior.prior.prior.prior.prior.prior.current_promise,
            std::move(
                other.prior.prior.prior.prior.prior.prior.current_promise));
        goto tail2;
      case State::kState3:
        Construct(
            &prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.current_promise));
        goto tail3;
      case State::kState4:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail4;
      case State::kState5:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail5;
      case State::kState6:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail6;
      case State::kState7:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail7;
      case State::kState8:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .next_factory));
  tail1:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(
            other.prior.prior.prior.prior.prior.prior.prior.next_factory));
  tail2:
    Construct(
        &prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.next_factory));
  tail3:
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.next_factory));
  tail4:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail5:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail6:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail7:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/9", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/9 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/9", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/9 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/9", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/9 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/9", this);
        }
        auto result = prior.prior.prior.prior.prior.current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/9 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/9", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult4* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 5/9 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits4::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits4::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits4::IsOk(*p)) {
          return PromiseResultTraits4::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits4::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState5;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState5: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 6/9", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult5* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 6/9 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits5::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits5::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits5::IsOk(*p)) {
          return PromiseResultTraits5::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits5::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState6;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState6: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 7/9", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult6* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 7/9 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits6::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits6::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits6::IsOk(*p)) {
          return PromiseResultTraits6::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits6::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState7;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState7: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 8/9", this);
        }
        auto result = prior.current_promise();
        PromiseResult7* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 8/9 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits7::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits7::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits7::IsOk(*p)) {
          return PromiseResultTraits7::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits7::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState8;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState8: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 9/9", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 9/9 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3, typename F4, typename F5,
          typename F6, typename F7, typename F8>
struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7, F8> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using NextFactory4 =
      OncePromiseFactory<typename PromiseResultTraits4::UnwrappedType, F4>;
  using Promise5 = typename NextFactory4::Promise;
  using PromiseResult5 = typename Promise5::Result;
  using PromiseResultTraits5 = Traits<PromiseResult5>;
  using NextFactory5 =
      OncePromiseFactory<typename PromiseResultTraits5::UnwrappedType, F5>;
  using Promise6 = typename NextFactory5::Promise;
  using PromiseResult6 = typename Promise6::Result;
  using PromiseResultTraits6 = Traits<PromiseResult6>;
  using NextFactory6 =
      OncePromiseFactory<typename PromiseResultTraits6::UnwrappedType, F6>;
  using Promise7 = typename NextFactory6::Promise;
  using PromiseResult7 = typename Promise7::Result;
  using PromiseResultTraits7 = Traits<PromiseResult7>;
  using NextFactory7 =
      OncePromiseFactory<typename PromiseResultTraits7::UnwrappedType, F7>;
  using Promise8 = typename NextFactory7::Promise;
  using PromiseResult8 = typename Promise8::Result;
  using PromiseResultTraits8 = Traits<PromiseResult8>;
  using NextFactory8 =
      OncePromiseFactory<typename PromiseResultTraits8::UnwrappedType, F8>;
  using Promise9 = typename NextFactory8::Promise;
  using PromiseResult9 = typename Promise9::Result;
  using PromiseResultTraits9 = Traits<PromiseResult9>;
  using Result = typename PromiseResultTraits9::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  struct Running4 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running3 prior;
      GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory4 next_factory;
  };
  struct Running5 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running4 prior;
      GPR_NO_UNIQUE_ADDRESS Promise5 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory5 next_factory;
  };
  struct Running6 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running5 prior;
      GPR_NO_UNIQUE_ADDRESS Promise6 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory6 next_factory;
  };
  struct Running7 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running6 prior;
      GPR_NO_UNIQUE_ADDRESS Promise7 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory7 next_factory;
  };
  struct Running8 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running7 prior;
      GPR_NO_UNIQUE_ADDRESS Promise8 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory8 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running8 prior;
    GPR_NO_UNIQUE_ADDRESS Promise9 current_promise;
  };
  enum class State : uint8_t {
    kState0,
    kState1,
    kState2,
    kState3,
    kState4,
    kState5,
    kState6,
    kState7,
    kState8,
    kState9
  };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3, F4&& f4, F5&& f5, F6&& f6,
           F7&& f7, F8&& f8, DebugLocation whence) noexcept
      : whence(whence) {
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
        std::forward<P>(p));
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::forward<F0>(f0));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F1>(f1));
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F2>(f2));
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F3>(f3));
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::forward<F4>(f4));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F5>(f5));
    Construct(&prior.prior.prior.next_factory, std::forward<F6>(f6));
    Construct(&prior.prior.next_factory, std::forward<F7>(f7));
    Construct(&prior.next_factory, std::forward<F8>(f8));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        goto tail0;
      case State::kState1:
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        goto tail3;
      case State::kState4:
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        goto tail4;
      case State::kState5:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail5;
      case State::kState6:
        Destruct(&prior.prior.prior.current_promise);
        goto tail6;
      case State::kState7:
        Destruct(&prior.prior.current_promise);
        goto tail7;
      case State::kState8:
        Destruct(&prior.current_promise);
        goto tail8;
      case State::kState9:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail1:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail2:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail3:
    Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
  tail4:
    Destruct(&prior.prior.prior.prior.prior.next_factory);
  tail5:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail6:
    Destruct(&prior.prior.prior.next_factory);
  tail7:
    Destruct(&prior.prior.next_factory);
  tail8:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.prior
            .next_factory);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise));
        goto tail1;
      case State::kState2:
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .current_promise));
        goto tail2;
      case State::kState3:
        Construct(
            &prior.prior.prior.prior.prior.prior.current_promise,
            std::move(
                other.prior.prior.prior.prior.prior.prior.current_promise));
        goto tail3;
      case State::kState4:
        Construct(
            &prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.current_promise));
        goto tail4;
      case State::kState5:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail5;
      case State::kState6:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail6;
      case State::kState7:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail7;
      case State::kState8:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail8;
      case State::kState9:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory));
  tail1:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .next_factory));
  tail2:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(
            other.prior.prior.prior.prior.prior.prior.prior.next_factory));
  tail3:
    Construct(
        &prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.next_factory));
  tail4:
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.next_factory));
  tail5:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail6:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail7:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail8:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/10", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory);
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/10", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/10", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/10", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/10", this);
        }
        auto result = prior.prior.prior.prior.prior.current_promise();
        PromiseResult4* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 5/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits4::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits4::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits4::IsOk(*p)) {
          return PromiseResultTraits4::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits4::CallFactory(
            &prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState5;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState5: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 6/10", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult5* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 6/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits5::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits5::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits5::IsOk(*p)) {
          return PromiseResultTraits5::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits5::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState6;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState6: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 7/10", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult6* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 7/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits6::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits6::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits6::IsOk(*p)) {
          return PromiseResultTraits6::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits6::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState7;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState7: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 8/10", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult7* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 8/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits7::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits7::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits7::IsOk(*p)) {
          return PromiseResultTraits7::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits7::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState8;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState8: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 9/10", this);
        }
        auto result = prior.current_promise();
        PromiseResult8* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 9/10 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits8::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits8::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits8::IsOk(*p)) {
          return PromiseResultTraits8::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits8::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState9;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState9: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 10/10", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 10/10 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3, typename F4, typename F5,
          typename F6, typename F7, typename F8, typename F9>
struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7, F8, F9> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using NextFactory4 =
      OncePromiseFactory<typename PromiseResultTraits4::UnwrappedType, F4>;
  using Promise5 = typename NextFactory4::Promise;
  using PromiseResult5 = typename Promise5::Result;
  using PromiseResultTraits5 = Traits<PromiseResult5>;
  using NextFactory5 =
      OncePromiseFactory<typename PromiseResultTraits5::UnwrappedType, F5>;
  using Promise6 = typename NextFactory5::Promise;
  using PromiseResult6 = typename Promise6::Result;
  using PromiseResultTraits6 = Traits<PromiseResult6>;
  using NextFactory6 =
      OncePromiseFactory<typename PromiseResultTraits6::UnwrappedType, F6>;
  using Promise7 = typename NextFactory6::Promise;
  using PromiseResult7 = typename Promise7::Result;
  using PromiseResultTraits7 = Traits<PromiseResult7>;
  using NextFactory7 =
      OncePromiseFactory<typename PromiseResultTraits7::UnwrappedType, F7>;
  using Promise8 = typename NextFactory7::Promise;
  using PromiseResult8 = typename Promise8::Result;
  using PromiseResultTraits8 = Traits<PromiseResult8>;
  using NextFactory8 =
      OncePromiseFactory<typename PromiseResultTraits8::UnwrappedType, F8>;
  using Promise9 = typename NextFactory8::Promise;
  using PromiseResult9 = typename Promise9::Result;
  using PromiseResultTraits9 = Traits<PromiseResult9>;
  using NextFactory9 =
      OncePromiseFactory<typename PromiseResultTraits9::UnwrappedType, F9>;
  using Promise10 = typename NextFactory9::Promise;
  using PromiseResult10 = typename Promise10::Result;
  using PromiseResultTraits10 = Traits<PromiseResult10>;
  using Result = typename PromiseResultTraits10::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  struct Running4 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running3 prior;
      GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory4 next_factory;
  };
  struct Running5 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running4 prior;
      GPR_NO_UNIQUE_ADDRESS Promise5 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory5 next_factory;
  };
  struct Running6 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running5 prior;
      GPR_NO_UNIQUE_ADDRESS Promise6 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory6 next_factory;
  };
  struct Running7 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running6 prior;
      GPR_NO_UNIQUE_ADDRESS Promise7 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory7 next_factory;
  };
  struct Running8 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running7 prior;
      GPR_NO_UNIQUE_ADDRESS Promise8 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory8 next_factory;
  };
  struct Running9 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running8 prior;
      GPR_NO_UNIQUE_ADDRESS Promise9 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory9 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running9 prior;
    GPR_NO_UNIQUE_ADDRESS Promise10 current_promise;
  };
  enum class State : uint8_t {
    kState0,
    kState1,
    kState2,
    kState3,
    kState4,
    kState5,
    kState6,
    kState7,
    kState8,
    kState9,
    kState10
  };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3, F4&& f4, F5&& f5, F6&& f6,
           F7&& f7, F8&& f8, F9&& f9, DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .current_promise,
              std::forward<P>(p));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::forward<F0>(f0));
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::forward<F1>(f1));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F2>(f2));
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F3>(f3));
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F4>(f4));
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::forward<F5>(f5));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F6>(f6));
    Construct(&prior.prior.prior.next_factory, std::forward<F7>(f7));
    Construct(&prior.prior.next_factory, std::forward<F8>(f8));
    Construct(&prior.next_factory, std::forward<F9>(f9));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        goto tail1;
      case State::kState2:
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail3;
      case State::kState4:
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        goto tail4;
      case State::kState5:
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        goto tail5;
      case State::kState6:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail6;
      case State::kState7:
        Destruct(&prior.prior.prior.current_promise);
        goto tail7;
      case State::kState8:
        Destruct(&prior.prior.current_promise);
        goto tail8;
      case State::kState9:
        Destruct(&prior.current_promise);
        goto tail9;
      case State::kState10:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .next_factory);
  tail1:
    Destruct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail2:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail3:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail4:
    Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
  tail5:
    Destruct(&prior.prior.prior.prior.prior.next_factory);
  tail6:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail7:
    Destruct(&prior.prior.prior.next_factory);
  tail8:
    Destruct(&prior.prior.next_factory);
  tail9:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .next_factory);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.prior
            .next_factory);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise));
        goto tail2;
      case State::kState3:
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .current_promise));
        goto tail3;
      case State::kState4:
        Construct(
            &prior.prior.prior.prior.prior.prior.current_promise,
            std::move(
                other.prior.prior.prior.prior.prior.prior.current_promise));
        goto tail4;
      case State::kState5:
        Construct(
            &prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.current_promise));
        goto tail5;
      case State::kState6:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail6;
      case State::kState7:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail7;
      case State::kState8:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail8;
      case State::kState9:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail9;
      case State::kState10:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .prior.prior.next_factory));
  tail1:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory));
  tail2:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .next_factory));
  tail3:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(
            other.prior.prior.prior.prior.prior.prior.prior.next_factory));
  tail4:
    Construct(
        &prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.next_factory));
  tail5:
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.next_factory));
  tail6:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail7:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail8:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail9:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/11", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                 .next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/11", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory);
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/11", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/11", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/11", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult4* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 5/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits4::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits4::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits4::IsOk(*p)) {
          return PromiseResultTraits4::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits4::CallFactory(
            &prior.prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState5;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState5: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 6/11", this);
        }
        auto result = prior.prior.prior.prior.prior.current_promise();
        PromiseResult5* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 6/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits5::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits5::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits5::IsOk(*p)) {
          return PromiseResultTraits5::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits5::CallFactory(
            &prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState6;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState6: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 7/11", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult6* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 7/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits6::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits6::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits6::IsOk(*p)) {
          return PromiseResultTraits6::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits6::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState7;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState7: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 8/11", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult7* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 8/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits7::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits7::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits7::IsOk(*p)) {
          return PromiseResultTraits7::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits7::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState8;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState8: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 9/11", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult8* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 9/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits8::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits8::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits8::IsOk(*p)) {
          return PromiseResultTraits8::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits8::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState9;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState9: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 10/11", this);
        }
        auto result = prior.current_promise();
        PromiseResult9* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 10/11 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits9::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits9::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits9::IsOk(*p)) {
          return PromiseResultTraits9::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits9::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState10;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState10: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 11/11", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 11/11 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3, typename F4, typename F5,
          typename F6, typename F7, typename F8, typename F9, typename F10>
struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using NextFactory4 =
      OncePromiseFactory<typename PromiseResultTraits4::UnwrappedType, F4>;
  using Promise5 = typename NextFactory4::Promise;
  using PromiseResult5 = typename Promise5::Result;
  using PromiseResultTraits5 = Traits<PromiseResult5>;
  using NextFactory5 =
      OncePromiseFactory<typename PromiseResultTraits5::UnwrappedType, F5>;
  using Promise6 = typename NextFactory5::Promise;
  using PromiseResult6 = typename Promise6::Result;
  using PromiseResultTraits6 = Traits<PromiseResult6>;
  using NextFactory6 =
      OncePromiseFactory<typename PromiseResultTraits6::UnwrappedType, F6>;
  using Promise7 = typename NextFactory6::Promise;
  using PromiseResult7 = typename Promise7::Result;
  using PromiseResultTraits7 = Traits<PromiseResult7>;
  using NextFactory7 =
      OncePromiseFactory<typename PromiseResultTraits7::UnwrappedType, F7>;
  using Promise8 = typename NextFactory7::Promise;
  using PromiseResult8 = typename Promise8::Result;
  using PromiseResultTraits8 = Traits<PromiseResult8>;
  using NextFactory8 =
      OncePromiseFactory<typename PromiseResultTraits8::UnwrappedType, F8>;
  using Promise9 = typename NextFactory8::Promise;
  using PromiseResult9 = typename Promise9::Result;
  using PromiseResultTraits9 = Traits<PromiseResult9>;
  using NextFactory9 =
      OncePromiseFactory<typename PromiseResultTraits9::UnwrappedType, F9>;
  using Promise10 = typename NextFactory9::Promise;
  using PromiseResult10 = typename Promise10::Result;
  using PromiseResultTraits10 = Traits<PromiseResult10>;
  using NextFactory10 =
      OncePromiseFactory<typename PromiseResultTraits10::UnwrappedType, F10>;
  using Promise11 = typename NextFactory10::Promise;
  using PromiseResult11 = typename Promise11::Result;
  using PromiseResultTraits11 = Traits<PromiseResult11>;
  using Result = typename PromiseResultTraits11::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  struct Running4 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running3 prior;
      GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory4 next_factory;
  };
  struct Running5 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running4 prior;
      GPR_NO_UNIQUE_ADDRESS Promise5 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory5 next_factory;
  };
  struct Running6 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running5 prior;
      GPR_NO_UNIQUE_ADDRESS Promise6 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory6 next_factory;
  };
  struct Running7 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running6 prior;
      GPR_NO_UNIQUE_ADDRESS Promise7 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory7 next_factory;
  };
  struct Running8 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running7 prior;
      GPR_NO_UNIQUE_ADDRESS Promise8 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory8 next_factory;
  };
  struct Running9 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running8 prior;
      GPR_NO_UNIQUE_ADDRESS Promise9 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory9 next_factory;
  };
  struct Running10 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running9 prior;
      GPR_NO_UNIQUE_ADDRESS Promise10 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory10 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running10 prior;
    GPR_NO_UNIQUE_ADDRESS Promise11 current_promise;
  };
  enum class State : uint8_t {
    kState0,
    kState1,
    kState2,
    kState3,
    kState4,
    kState5,
    kState6,
    kState7,
    kState8,
    kState9,
    kState10,
    kState11
  };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3, F4&& f4, F5&& f5, F6&& f6,
           F7&& f7, F8&& f8, F9&& f9, F10&& f10, DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .current_promise,
              std::forward<P>(p));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::forward<F0>(f0));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::forward<F1>(f1));
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::forward<F2>(f2));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F3>(f3));
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F4>(f4));
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F5>(f5));
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::forward<F6>(f6));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F7>(f7));
    Construct(&prior.prior.prior.next_factory, std::forward<F8>(f8));
    Construct(&prior.prior.next_factory, std::forward<F9>(f9));
    Construct(&prior.next_factory, std::forward<F10>(f10));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        goto tail2;
      case State::kState3:
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail3;
      case State::kState4:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail4;
      case State::kState5:
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        goto tail5;
      case State::kState6:
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        goto tail6;
      case State::kState7:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail7;
      case State::kState8:
        Destruct(&prior.prior.prior.current_promise);
        goto tail8;
      case State::kState9:
        Destruct(&prior.prior.current_promise);
        goto tail9;
      case State::kState10:
        Destruct(&prior.current_promise);
        goto tail10;
      case State::kState11:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .next_factory);
  tail1:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .next_factory);
  tail2:
    Destruct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail3:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail4:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail5:
    Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
  tail6:
    Destruct(&prior.prior.prior.prior.prior.next_factory);
  tail7:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail8:
    Destruct(&prior.prior.prior.next_factory);
  tail9:
    Destruct(&prior.prior.next_factory);
  tail10:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .next_factory);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.prior
            .next_factory);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .prior.current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.current_promise));
        goto tail2;
      case State::kState3:
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise));
        goto tail3;
      case State::kState4:
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .current_promise));
        goto tail4;
      case State::kState5:
        Construct(
            &prior.prior.prior.prior.prior.prior.current_promise,
            std::move(
                other.prior.prior.prior.prior.prior.prior.current_promise));
        goto tail5;
      case State::kState6:
        Construct(
            &prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.current_promise));
        goto tail6;
      case State::kState7:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail7;
      case State::kState8:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail8;
      case State::kState9:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail9;
      case State::kState10:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail10;
      case State::kState11:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .prior.prior.prior.next_factory));
  tail1:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .prior.prior.next_factory));
  tail2:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory));
  tail3:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .next_factory));
  tail4:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(
            other.prior.prior.prior.prior.prior.prior.prior.next_factory));
  tail5:
    Construct(
        &prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.next_factory));
  tail6:
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.next_factory));
  tail7:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail8:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail9:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail10:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/12", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                 .next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/12", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                 .next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/12", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory);
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/12", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/12", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult4* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 5/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits4::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits4::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits4::IsOk(*p)) {
          return PromiseResultTraits4::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits4::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState5;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState5: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 6/12", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult5* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 6/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits5::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits5::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits5::IsOk(*p)) {
          return PromiseResultTraits5::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits5::CallFactory(
            &prior.prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState6;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState6: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 7/12", this);
        }
        auto result = prior.prior.prior.prior.prior.current_promise();
        PromiseResult6* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 7/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits6::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits6::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits6::IsOk(*p)) {
          return PromiseResultTraits6::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits6::CallFactory(
            &prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState7;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState7: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 8/12", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult7* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 8/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits7::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits7::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits7::IsOk(*p)) {
          return PromiseResultTraits7::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits7::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState8;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState8: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 9/12", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult8* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 9/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits8::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits8::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits8::IsOk(*p)) {
          return PromiseResultTraits8::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits8::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState9;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState9: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 10/12", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult9* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 10/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits9::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits9::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits9::IsOk(*p)) {
          return PromiseResultTraits9::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits9::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState10;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState10: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 11/12", this);
        }
        auto result = prior.current_promise();
        PromiseResult10* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 11/12 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits10::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits10::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits10::IsOk(*p)) {
          return PromiseResultTraits10::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits10::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState11;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState11: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 12/12", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 12/12 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

template <template <typename> class Traits, typename P, typename F0,
          typename F1, typename F2, typename F3, typename F4, typename F5,
          typename F6, typename F7, typename F8, typename F9, typename F10,
          typename F11>
struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11> {
  using Promise0 = PromiseLike<P>;
  using PromiseResult0 = typename Promise0::Result;
  using PromiseResultTraits0 = Traits<PromiseResult0>;
  using NextFactory0 =
      OncePromiseFactory<typename PromiseResultTraits0::UnwrappedType, F0>;
  using Promise1 = typename NextFactory0::Promise;
  using PromiseResult1 = typename Promise1::Result;
  using PromiseResultTraits1 = Traits<PromiseResult1>;
  using NextFactory1 =
      OncePromiseFactory<typename PromiseResultTraits1::UnwrappedType, F1>;
  using Promise2 = typename NextFactory1::Promise;
  using PromiseResult2 = typename Promise2::Result;
  using PromiseResultTraits2 = Traits<PromiseResult2>;
  using NextFactory2 =
      OncePromiseFactory<typename PromiseResultTraits2::UnwrappedType, F2>;
  using Promise3 = typename NextFactory2::Promise;
  using PromiseResult3 = typename Promise3::Result;
  using PromiseResultTraits3 = Traits<PromiseResult3>;
  using NextFactory3 =
      OncePromiseFactory<typename PromiseResultTraits3::UnwrappedType, F3>;
  using Promise4 = typename NextFactory3::Promise;
  using PromiseResult4 = typename Promise4::Result;
  using PromiseResultTraits4 = Traits<PromiseResult4>;
  using NextFactory4 =
      OncePromiseFactory<typename PromiseResultTraits4::UnwrappedType, F4>;
  using Promise5 = typename NextFactory4::Promise;
  using PromiseResult5 = typename Promise5::Result;
  using PromiseResultTraits5 = Traits<PromiseResult5>;
  using NextFactory5 =
      OncePromiseFactory<typename PromiseResultTraits5::UnwrappedType, F5>;
  using Promise6 = typename NextFactory5::Promise;
  using PromiseResult6 = typename Promise6::Result;
  using PromiseResultTraits6 = Traits<PromiseResult6>;
  using NextFactory6 =
      OncePromiseFactory<typename PromiseResultTraits6::UnwrappedType, F6>;
  using Promise7 = typename NextFactory6::Promise;
  using PromiseResult7 = typename Promise7::Result;
  using PromiseResultTraits7 = Traits<PromiseResult7>;
  using NextFactory7 =
      OncePromiseFactory<typename PromiseResultTraits7::UnwrappedType, F7>;
  using Promise8 = typename NextFactory7::Promise;
  using PromiseResult8 = typename Promise8::Result;
  using PromiseResultTraits8 = Traits<PromiseResult8>;
  using NextFactory8 =
      OncePromiseFactory<typename PromiseResultTraits8::UnwrappedType, F8>;
  using Promise9 = typename NextFactory8::Promise;
  using PromiseResult9 = typename Promise9::Result;
  using PromiseResultTraits9 = Traits<PromiseResult9>;
  using NextFactory9 =
      OncePromiseFactory<typename PromiseResultTraits9::UnwrappedType, F9>;
  using Promise10 = typename NextFactory9::Promise;
  using PromiseResult10 = typename Promise10::Result;
  using PromiseResultTraits10 = Traits<PromiseResult10>;
  using NextFactory10 =
      OncePromiseFactory<typename PromiseResultTraits10::UnwrappedType, F10>;
  using Promise11 = typename NextFactory10::Promise;
  using PromiseResult11 = typename Promise11::Result;
  using PromiseResultTraits11 = Traits<PromiseResult11>;
  using NextFactory11 =
      OncePromiseFactory<typename PromiseResultTraits11::UnwrappedType, F11>;
  using Promise12 = typename NextFactory11::Promise;
  using PromiseResult12 = typename Promise12::Result;
  using PromiseResultTraits12 = Traits<PromiseResult12>;
  using Result = typename PromiseResultTraits12::WrappedType;
  struct Running0 {
    GPR_NO_UNIQUE_ADDRESS Promise0 current_promise;
    GPR_NO_UNIQUE_ADDRESS NextFactory0 next_factory;
  };
  struct Running1 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running0 prior;
      GPR_NO_UNIQUE_ADDRESS Promise1 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory1 next_factory;
  };
  struct Running2 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running1 prior;
      GPR_NO_UNIQUE_ADDRESS Promise2 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory2 next_factory;
  };
  struct Running3 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running2 prior;
      GPR_NO_UNIQUE_ADDRESS Promise3 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory3 next_factory;
  };
  struct Running4 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running3 prior;
      GPR_NO_UNIQUE_ADDRESS Promise4 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory4 next_factory;
  };
  struct Running5 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running4 prior;
      GPR_NO_UNIQUE_ADDRESS Promise5 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory5 next_factory;
  };
  struct Running6 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running5 prior;
      GPR_NO_UNIQUE_ADDRESS Promise6 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory6 next_factory;
  };
  struct Running7 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running6 prior;
      GPR_NO_UNIQUE_ADDRESS Promise7 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory7 next_factory;
  };
  struct Running8 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running7 prior;
      GPR_NO_UNIQUE_ADDRESS Promise8 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory8 next_factory;
  };
  struct Running9 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running8 prior;
      GPR_NO_UNIQUE_ADDRESS Promise9 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory9 next_factory;
  };
  struct Running10 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running9 prior;
      GPR_NO_UNIQUE_ADDRESS Promise10 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory10 next_factory;
  };
  struct Running11 {
    union {
      GPR_NO_UNIQUE_ADDRESS Running10 prior;
      GPR_NO_UNIQUE_ADDRESS Promise11 current_promise;
    };
    GPR_NO_UNIQUE_ADDRESS NextFactory11 next_factory;
  };
  union {
    GPR_NO_UNIQUE_ADDRESS Running11 prior;
    GPR_NO_UNIQUE_ADDRESS Promise12 current_promise;
  };
  enum class State : uint8_t {
    kState0,
    kState1,
    kState2,
    kState3,
    kState4,
    kState5,
    kState6,
    kState7,
    kState8,
    kState9,
    kState10,
    kState11,
    kState12
  };
  GPR_NO_UNIQUE_ADDRESS State state = State::kState0;
  GPR_NO_UNIQUE_ADDRESS DebugLocation whence;

  SeqState(P&& p, F0&& f0, F1&& f1, F2&& f2, F3&& f3, F4&& f4, F5&& f5, F6&& f6,
           F7&& f7, F8&& f8, F9&& f9, F10&& f10, F11&& f11,
           DebugLocation whence) noexcept
      : whence(whence) {
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .prior.current_promise,
              std::forward<P>(p));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .prior.next_factory,
              std::forward<F0>(f0));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::forward<F1>(f1));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::forward<F2>(f2));
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::forward<F3>(f3));
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F4>(f4));
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F5>(f5));
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              std::forward<F6>(f6));
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::forward<F7>(f7));
    Construct(&prior.prior.prior.prior.next_factory, std::forward<F8>(f8));
    Construct(&prior.prior.prior.next_factory, std::forward<F9>(f9));
    Construct(&prior.prior.next_factory, std::forward<F10>(f10));
    Construct(&prior.next_factory, std::forward<F11>(f11));
  }
  ~SeqState() {
    switch (state) {
      case State::kState0:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.prior.current_promise);
        goto tail0;
      case State::kState1:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.current_promise);
        goto tail1;
      case State::kState2:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        goto tail2;
      case State::kState3:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        goto tail3;
      case State::kState4:
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail4;
      case State::kState5:
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        goto tail5;
      case State::kState6:
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        goto tail6;
      case State::kState7:
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        goto tail7;
      case State::kState8:
        Destruct(&prior.prior.prior.prior.current_promise);
        goto tail8;
      case State::kState9:
        Destruct(&prior.prior.prior.current_promise);
        goto tail9;
      case State::kState10:
        Destruct(&prior.prior.current_promise);
        goto tail10;
      case State::kState11:
        Destruct(&prior.current_promise);
        goto tail11;
      case State::kState12:
        Destruct(&current_promise);
        return;
    }
  tail0:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .prior.next_factory);
  tail1:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .next_factory);
  tail2:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .next_factory);
  tail3:
    Destruct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail4:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail5:
    Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
  tail6:
    Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
  tail7:
    Destruct(&prior.prior.prior.prior.prior.next_factory);
  tail8:
    Destruct(&prior.prior.prior.prior.next_factory);
  tail9:
    Destruct(&prior.prior.prior.next_factory);
  tail10:
    Destruct(&prior.prior.next_factory);
  tail11:
    Destruct(&prior.next_factory);
  }
  SeqState(const SeqState& other) noexcept
      : state(other.state), whence(other.whence) {
    GPR_ASSERT(state == State::kState0);
    Construct(&prior.current_promise, other.prior.current_promise);
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                  .next_factory);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.prior
            .next_factory);
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        other.prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.prior.next_factory,
              other.prior.prior.prior.prior.next_factory);
    Construct(&prior.prior.prior.next_factory,
              other.prior.prior.prior.next_factory);
    Construct(&prior.prior.next_factory, other.prior.prior.next_factory);
    Construct(&prior.next_factory, other.prior.next_factory);
  }
  SeqState& operator=(const SeqState& other) = delete;
  SeqState(SeqState&& other) noexcept
      : state(other.state), whence(other.whence) {
    switch (state) {
      case State::kState0:
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                 .prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                          .prior.prior.prior.prior.current_promise));
        goto tail0;
      case State::kState1:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .prior.current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.prior.prior.current_promise));
        goto tail1;
      case State::kState2:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.prior.current_promise));
        goto tail2;
      case State::kState3:
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .prior.prior.current_promise));
        goto tail3;
      case State::kState4:
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise));
        goto tail4;
      case State::kState5:
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.prior.prior.prior
                                .current_promise));
        goto tail5;
      case State::kState6:
        Construct(
            &prior.prior.prior.prior.prior.prior.current_promise,
            std::move(
                other.prior.prior.prior.prior.prior.prior.current_promise));
        goto tail6;
      case State::kState7:
        Construct(
            &prior.prior.prior.prior.prior.current_promise,
            std::move(other.prior.prior.prior.prior.prior.current_promise));
        goto tail7;
      case State::kState8:
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.prior.current_promise));
        goto tail8;
      case State::kState9:
        Construct(&prior.prior.prior.current_promise,
                  std::move(other.prior.prior.prior.current_promise));
        goto tail9;
      case State::kState10:
        Construct(&prior.prior.current_promise,
                  std::move(other.prior.prior.current_promise));
        goto tail10;
      case State::kState11:
        Construct(&prior.current_promise,
                  std::move(other.prior.current_promise));
        goto tail11;
      case State::kState12:
        Construct(&current_promise, std::move(other.current_promise));
        return;
    }
  tail0:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .prior.prior.prior.prior.next_factory));
  tail1:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .prior.prior.prior.next_factory));
  tail2:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                   .next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .prior.prior.next_factory));
  tail3:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory));
  tail4:
    Construct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.prior.prior.prior
                            .next_factory));
  tail5:
    Construct(
        &prior.prior.prior.prior.prior.prior.prior.next_factory,
        std::move(
            other.prior.prior.prior.prior.prior.prior.prior.next_factory));
  tail6:
    Construct(
        &prior.prior.prior.prior.prior.prior.next_factory,
        std::move(other.prior.prior.prior.prior.prior.prior.next_factory));
  tail7:
    Construct(&prior.prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.prior.next_factory));
  tail8:
    Construct(&prior.prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.prior.next_factory));
  tail9:
    Construct(&prior.prior.prior.next_factory,
              std::move(other.prior.prior.prior.next_factory));
  tail10:
    Construct(&prior.prior.next_factory,
              std::move(other.prior.prior.next_factory));
  tail11:
    Construct(&prior.next_factory, std::move(other.prior.next_factory));
  }
  SeqState& operator=(SeqState&& other) = delete;
  Poll<Result> PollOnce() {
    switch (state) {
      case State::kState0: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 1/13", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .prior.prior.prior.current_promise();
        PromiseResult0* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 1/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits0::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits0::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits0::IsOk(*p)) {
          return PromiseResultTraits0::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.prior.current_promise);
        auto next_promise = PromiseResultTraits0::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                 .prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .prior.current_promise,
                  std::move(next_promise));
        state = State::kState1;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState1: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 2/13", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .prior.prior.current_promise();
        PromiseResult1* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 2/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits1::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits1::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits1::IsOk(*p)) {
          return PromiseResultTraits1::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.current_promise);
        auto next_promise = PromiseResultTraits1::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                 .next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(next_promise));
        state = State::kState2;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState2: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 3/13", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .prior.current_promise();
        PromiseResult2* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 3/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits2::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits2::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits2::IsOk(*p)) {
          return PromiseResultTraits2::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        auto next_promise = PromiseResultTraits2::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                 .next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                       .current_promise,
                  std::move(next_promise));
        state = State::kState3;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState3: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 4/13", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.prior.prior.prior
                          .current_promise();
        PromiseResult3* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 4/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits3::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits3::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits3::IsOk(*p)) {
          return PromiseResultTraits3::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .current_promise);
        auto next_promise = PromiseResultTraits3::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.prior
                      .next_factory);
        Construct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise,
            std::move(next_promise));
        state = State::kState4;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState4: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 5/13", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult4* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 5/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits4::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits4::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits4::IsOk(*p)) {
          return PromiseResultTraits4::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(
            &prior.prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits4::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState5;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState5: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 6/13", this);
        }
        auto result =
            prior.prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult5* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 6/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits5::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits5::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits5::IsOk(*p)) {
          return PromiseResultTraits5::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits5::CallFactory(
            &prior.prior.prior.prior.prior.prior.prior.next_factory,
            std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState6;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState6: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 7/13", this);
        }
        auto result = prior.prior.prior.prior.prior.prior.current_promise();
        PromiseResult6* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 7/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits6::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits6::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits6::IsOk(*p)) {
          return PromiseResultTraits6::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits6::CallFactory(
            &prior.prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState7;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState7: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 8/13", this);
        }
        auto result = prior.prior.prior.prior.prior.current_promise();
        PromiseResult7* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 8/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits7::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits7::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits7::IsOk(*p)) {
          return PromiseResultTraits7::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits7::CallFactory(
            &prior.prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.prior.current_promise,
                  std::move(next_promise));
        state = State::kState8;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState8: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 9/13", this);
        }
        auto result = prior.prior.prior.prior.current_promise();
        PromiseResult8* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 9/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits8::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits8::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits8::IsOk(*p)) {
          return PromiseResultTraits8::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits8::CallFactory(
            &prior.prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.prior.next_factory);
        Construct(&prior.prior.prior.current_promise, std::move(next_promise));
        state = State::kState9;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState9: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 10/13", this);
        }
        auto result = prior.prior.prior.current_promise();
        PromiseResult9* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 10/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits9::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits9::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits9::IsOk(*p)) {
          return PromiseResultTraits9::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.prior.current_promise);
        auto next_promise = PromiseResultTraits9::CallFactory(
            &prior.prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.prior.next_factory);
        Construct(&prior.prior.current_promise, std::move(next_promise));
        state = State::kState10;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState10: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 11/13", this);
        }
        auto result = prior.prior.current_promise();
        PromiseResult10* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 11/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits10::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits10::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits10::IsOk(*p)) {
          return PromiseResultTraits10::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.prior.current_promise);
        auto next_promise = PromiseResultTraits10::CallFactory(
            &prior.prior.next_factory, std::move(*p));
        Destruct(&prior.prior.next_factory);
        Construct(&prior.current_promise, std::move(next_promise));
        state = State::kState11;
      }
        ABSL_FALLTHROUGH_INTENDED;
      case State::kState11: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 12/13", this);
        }
        auto result = prior.current_promise();
        PromiseResult11* p = result.value_if_ready();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(
              whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
              "seq[%p]: poll step 12/13 gets %s", this,
              p != nullptr
                  ? (PromiseResultTraits11::IsOk(*p)
                         ? "ready"
                         : absl::StrCat("early-error:",
                                        PromiseResultTraits11::ErrorString(*p))
                               .c_str())
                  : "pending");
        }
        if (p == nullptr) return Pending{};
        if (!PromiseResultTraits11::IsOk(*p)) {
          return PromiseResultTraits11::template ReturnValue<Result>(
              std::move(*p));
        }
        Destruct(&prior.current_promise);
        auto next_promise = PromiseResultTraits11::CallFactory(
            &prior.next_factory, std::move(*p));
        Destruct(&prior.next_factory);
        Construct(&current_promise, std::move(next_promise));
        state = State::kState12;
      }
        ABSL_FALLTHROUGH_INTENDED;
      default:
      case State::kState12: {
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: begin poll step 13/13", this);
        }
        auto result = current_promise();
        if (grpc_trace_promise_primitives.enabled()) {
          gpr_log(whence.file(), whence.line(), GPR_LOG_SEVERITY_DEBUG,
                  "seq[%p]: poll step 13/13 gets %s", this,
                  result.ready() ? "ready" : "pending");
        }
        auto* p = result.value_if_ready();
        if (p == nullptr) return Pending{};
        return Result(std::move(*p));
      }
    }
  }
};

}  // namespace promise_detail
}  // namespace grpc_core

#endif  // GRPC_SRC_CORE_LIB_PROMISE_DETAIL_SEQ_STATE_H