Goal:
    x : t  y : t  Heq_anonymous : true = eqb x y
  ============================
   (x = y)


DEBUG:Going to execute:
Tactics.autoinjection ltac:(Tactics.inject)
Level 4: Backtrace:

Tactic failure (level 2).
Level 4: Backtrace:

Tactic failure (level 1).
Level 3: Backtrace:

Tactic failure (level 1).
Level 2: Backtrace:

Tactic failure.
Level 1: Backtrace:

Tactic failure.
Level 0: Backtrace:

Tactic failure.