---- h1
10
---- h2
3
10
0
---- h3
10
30
4
---- inv
10
match1.lean:82:0-82:73: error: type mismatch during dependent match-elimination at pattern variable 'w' with type
  VecPred P Vec.nil
expected type
  VecPred P tail✝
[false, true, true]
match1.lean:119:0-119:41: error: dependent match elimination failed, inaccessible pattern found
  .(j + j)
constructor expected
[false, true, true]
match1.lean:136:7-136:22: error: invalid match-expression, type of pattern variable 'a' contains metavariables
  ?m
fun x => ?m x : ?m × ?m → ?m
fun x =>
  match x with
  | (a, b) => a + b : Nat × Nat → Nat
fun x =>
  match x with
  | (a, b) => a && b : Bool × Bool → Bool
fun x =>
  match x with
  | (a, b) => a + b : Nat × Nat → Nat
fun x x_1 =>
  match x, x_1 with
  | some a, some b => some (a + b)
  | x, x_2 => none : Option Nat → Option Nat → Option Nat
fun x =>
  (match x : Nat → Nat → Nat with
    | 0 => id
    | Nat.succ x => id)
    x : Nat → Nat
fun x =>
  match x with
  | #[1, 2] => 2
  | #[] => 0
  | #[3, 4, 5] => 3
  | x => 4 : Array Nat → Nat
g.match_1 : (motive : List ?m → Sort u_2) →
  (x : List ?m) → ((a : ?m) → motive [a]) → ((x : List ?m) → motive x) → motive x
fun e => nomatch e : Empty → False