import Mathlib.MeasureTheory.Order.Lattice
import Mathlib.Probability.Kernel.Composition.Prod
import Mathlib.Probability.Kernel.Composition.CompProd
import Mathlib.MeasureTheory.MeasurableSpace.Embedding
import Lean.Elab.Tactic.Location
import Lean.Meta.DecLevel
import Lean.Meta.Transform
import Lean.Util.Recognizers
import Lean.Meta.Tactic.Replace
import Lean.Meta.Tactic.Rewrite
import Mathlib.Probability.Kernel.Deterministic
import Mathlib.Combinatorics.Quiver.ReflQuiver
import Mathlib.Probability.Kernel.Category.SFinKer
import Mathlib.MeasureTheory.Integral.Lebesgue.Countable

/-! # Standalone extraction for `getUniverseFromEq`
Definitions are copied verbatim; theorem proofs are replaced by `sorry`.
Auto-generated by Referee. -/

set_option quotPrecheck false

-- Namespace stubs (so later `open`s resolve).
namespace Finset
end Finset
namespace Lean
end Lean
namespace Lean.Meta
end Lean.Meta
namespace ProbabilityTheory
end ProbabilityTheory
namespace ProbabilityTheory.Kernel
end ProbabilityTheory.Kernel

-- ═══ ForMathlib.MeasureTheory.Order.Lattice ═══
section
open Finset
variable {α δ : Type*} [MeasurableSpace δ] [SemilatticeInf α] {m : MeasurableSpace α} [MeasurableInf₂ α]
attribute [to_dual existing] MeasurableInf₂
end

-- ═══ Tactic.KernelHom.Tactic.HomKernel ═══
section
public meta section
open Lean Elab Tactic Meta CategoryTheory Parser.Tactic ProbabilityTheory MonoidalCategory
open ProbabilityTheory.Kernel

/-- Get the universe level from the left side of an equality expression. -/
def getUniverseFromEq (eq : Expr) : MetaM Level := do
  let eq ← instantiateMVars eq
  let eq ← zetaReduce eq
  let eq ← whnf eq
  let eq := eq.consumeMData
  let some (_, lhs, _) := eq.eq? | throwError "Expected an equality, got: {eq}."
  let l ← getLevel (← inferType lhs)
  match l with
  | Level.succ l' => return l'
  | _ => throwError "Expected a universe level ≥ 1, got: {l}"

end