error_loc_bug.lean:74:17: error: type mismatch at application
  weakening2 (OrI₁ Γ A B H)
term
  OrI₁ Γ A B H
has type
  Γ ⊢ A ∨ B
but is expected to have type
  Γ ⊢ ⌞A ∧ B⌟
The following identifier(s) are introduced as free variables by the left-hand-side of the equation:
  Γ A B Δ H Hs