myprod.fst p : ℕ
myprod.fst p : ℕ
myprod.snd p : ℕ
myprod.snd p : ℕ
myprod.fst p : ℕ
myprod.fst p : ℕ
myprod.snd p : ℕ
myprod.snd p : ℕ
f (myprod.fst p) : ℕ
myprod.fst p + myprod.snd p : ℕ
λ (c : car), position.x (car.pos c) : 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
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
proj_notation.lean:40:18: error: invalid projection, structure expected
  n
has type
  ℕ
myprod.fst p : ℕ
myprod.snd p : ℕ
λ (c : car), position.y (car.pos c) : car → ℕ