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module Random =
  open System
  let private r = new Random()
  let coinToss = fun _ -> r.Next(0,2)

let printNumbers n =
  match n % 2 = 0 with
  | true  -> printfn "Even nr. %i" n
  | false -> printfn "Odd nr. %i" n

let printNumbers' n =
  // Missed "else" statement is found at runtime					
  if n % 2 = 0
  then printfn "Even nr. %i" n

List.init 10 (Random.coinToss)
|> List.iter printNumbers

List.init 10 (Random.coinToss)
|> List.iter printNumbers'

>
module Random = begin
  val private r : System.Random
  val coinToss : 'a -> int
end
val printNumbers : n:int -> unit
val printNumbers' : n:int -> unit

> Even nr. 0
Odd nr. 1
Even nr. 0
Odd nr. 1
Even nr. 0
Odd nr. 1
Even nr. 0
Even nr. 0
Odd nr. 1
Odd nr. 1
val it : unit = ()

> Even nr. 0
Even nr. 0
Even nr. 0
Even nr. 0
Even nr. 0
val it : unit = ()

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let printNumbers'' n =
  // Missed "false" match is found at compile-time
  match n % 2 = 0 with
  | true  -> printfn "Even nr. %i" n

List.init 10 (Random.coinToss)
|> List.iter printNumbers''

>
/Users/mon/tmp/conditionalexpressionsVSpatternmatch.fsx(22,9): error FS0025: Incomplete pattern matches on this expression. For example, the value 'false' may indicate a case not covered by the pattern(s).