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


DEBUG:Going to execute:
intro
Level 2: Backtrace:

The goal is not a product.
Level 2: Backtrace:

The goal is not a product.
Level 2: Backtrace:

The goal is not a product.
Level 2: Backtrace:

The goal is not a product.