550.lean:43:72: error:invalid 'rewrite' tactic, step produced type incorrect term, details: type mismatch at application eq.symm linv term linv has type finv ∘ func = id but is expected to have type x = id rewrite step failed using pattern finv_1 ∘ func_1 proof state: A : Type, f : bijection A, func finv : A → A, linv : finv ∘ func = id, rinv : func ∘ finv = id ⊢ mk (finv ∘ func) (finv ∘ func) (eq.rec (eq.rec (eq.rec (eq.rec (eq.rec (eq.refl id) (eq.symm linv)) (eq.symm (compose.left_id func))) (eq.symm rinv)) (function.compose.assoc func finv func)) (eq.symm (function.compose.assoc finv func (finv ∘ func)))) (eq.rec (eq.rec (eq.rec (eq.rec (eq.rec (eq.refl id) (eq.symm linv)) (eq.symm (compose.right_id finv))) (eq.symm rinv)) (eq.symm (function.compose.assoc finv func finv))) (function.compose.assoc (finv ∘ func) finv func)) = id 550.lean:43:44: error: don't know how to synthesize placeholder A : Type, f : bijection A, func finv : A → A, linv : finv ∘ func = id, rinv : func ∘ finv = id ⊢ inv (mk func finv linv rinv) ∘b mk func finv linv rinv = id 550.lean:43:2: error: failed to add declaration 'bijection.inv.linv' to environment, value has metavariables remark: set 'formatter.hide_full_terms' to false to see the complete term λ (A : Type) (f : …), bijection.rec_on f ?M_1