Failed to solve the following constraints:
  _64 := λ {A} {x} E → J (_56 (E = E)) E [blocked on problem 65]
  [65, 77] _63 (A' = A) = x : A
  [55, 59] x = _63 (A' = A) : A
  _55 := λ {A} {x} E → refl [blocked on problem 55]
Unsolved metas at the following locations:
  Issue920a.agda:26,52-56
  Issue920a.agda:26,49-50
  Issue920a.agda:26,23-58
