893.hlean:3:2: error:invalid 'induction' tactic, invalid 'induction' tactic, argument #3 of major premise 'H' type is an index, but it occurs in previous arguments
proof state:
A : Type,
f : A → A,
a : A,
H : f a = a
⊢ unit
893.hlean:5:0: error: don't know how to synthesize placeholder
A : Type,
f : A → A,
a : A,
H : f a = a
⊢ unit
893.hlean:5:0: error: failed to add declaration 'example' to environment, value has metavariables
remark: set 'formatter.hide_full_terms' to false to see the complete term
  ?M_1