Cannot read property 'ctor/height' of undefined

[jinjor]

This code causes an error: Cannot read property 'ctor' of undefined.

import Html exposing (..)

main =
  text buggy

-- Cannot read property 'ctor' of undefined
buggy : String
buggy =
  let
    list =
      List.map
        (\_ -> List.length list)
        [0]
  in
    ""

Lambda function is trying to use undefined value. I'm not sure if compiler can detect this error statically.

The same thing happens with Array.

import Html exposing (..)
import Array exposing (Array)

main =
  text buggy

-- Cannot read property 'height' of undefined
buggy : String
buggy =
  let
    array =
      Array.map
        (\_ -> Array.length array)
        (Array.fromList [0])
  in
    ""

Maybe you wonder why I was trying to access undefined value like this? In my case, the same name variable was predefined as an argument of the function. So I was not aware the new variable was sealing the other.

[jinjor]

Oops, I found the same issue.

[jinjor]

Oops, I found the same issue.