1277.lean:8:2: error: rewrite tactic failed, motive is not type correct
nested exception message:
check failed, application type mismatch (use 'set_option trace.check true' for additional details)
state:
α₁ : Type,
α₂ : α₁ → Type,
f₁ : α₁ → α₁,
f₂ : Π ⦃a : α₁⦄, α₂ a → α₂ (f₁ a),
eq₁ : f₁ = id
⊢ map f₁ f₂ = id