F# Result applicative accumulating errors in a list

ResultErrorListApplicative.fs

type Test =
    { A : string
      B : int
      C : float
    }

let buildTest a b c =
    { A = a
      B = b
      C = c
    }

let a = Error ["No a"]
let b = Error ["No b"]
let c = Error ["No c"]

let (<*>) (res1 : Result<('a -> 'c), 'b list>) (res2 : Result<'a, 'b list>) : Result<'c, 'b list> =
    match res1, res2 with
    | Error err1, Error err2 -> Error (List.append err1 err2)
    | Ok f, Error err2 -> Error err2
    | Error err1, Ok a -> Error err1
    | Ok f, Ok a -> Ok <| f a

let f = Ok buildTest
let x = f <*> a <*> b <*> c