p^.fst : ℕ
p^.fst : ℕ
p^.snd : ℕ
p^.snd : ℕ
p^.fst : ℕ
p^.fst : ℕ
p^.snd : ℕ
p^.snd : ℕ
f (p^.fst) : ℕ
p^.fst + p^.snd : ℕ
λ (c : car), (c^.pos)^.x : car → ℕ
proj_notation.lean:34:18: error: invalid '~>' notation, 'fst' is not a valid "field" because environment does not contain 'car.fst'
  c
which has type
  car
λ (c : car), sorry : Π (c : car), delayed[?M_1]
proj_notation.lean:36:19: error: invalid projection, index must be greater than 0
proj_notation.lean:38:18: error: invalid projection, structure has only 2 field(s)
  c
which has type
  car
λ (c : car), sorry : Π (c : car), delayed[?M_1]
proj_notation.lean:40:18: error: invalid projection, structure expected
  n
has type
  ℕ
λ (n : ℕ), sorry : Π (n : ℕ), delayed[?M_1]
p^.fst : ℕ
p^.snd : ℕ
λ (c : car), (c^.pos)^.y : car → ℕ