Goal:
  
  A : Type
  B : Type
  P : A -> B -> Prop
  b : A -> B -> bool
  f : forall (x : A) (y : B), reflect (P x y) (b x y)
  x : A
  y : B
  ============================
   (reflect (P x y) (b x y))


DEBUG:Going to execute:
solve
[ trivial
with eq_true
| Ltac.reflexivity
| Ltac.symmetry; trivial
| contradiction ]