Array.append mutates first argument

[AdamLuotonen]

Hi!

I think there is a problem with Array.append, as it mutates the first array parameter sent to it. To reproduce, run the following in elm-repl:

> import Array
> a = Array.fromList [1,2,3]
Array.fromList [1,2,3] : Array.Array number
> b = Array.fromList [4,5,6]
Array.fromList [4,5,6] : Array.Array number
> c = Array.append a b
Array.fromList [1,2,3,4,5,6] : Array.Array number
> a
Array.fromList [1,2,3,4,5,6] : Array.Array number

a should still be [1,2,3] here? I'm running Elm 0.17.1 on Windows.

[process-bot]

Thanks for the issue! Make sure it satisfies this checklist. My human colleagues will appreciate it!

Here is what to expect next, and if anyone wants to comment, keep these things in mind.

[process-bot]

Thanks for the issue! Make sure it satisfies this checklist. My human colleagues will appreciate it!

Here is what to expect next, and if anyone wants to comment, keep these things in mind.

[lukewestby]

Referencing #649

[lukewestby]

Referencing #649

[evancz]

I added this to #649, track there. Also, there is progress on a mostly Elm implementation that should fix a lot of these issues!

[evancz]

I added this to #649, track there. Also, there is progress on a mostly Elm implementation that should fix a lot of these issues!

[eike]

Since this problem still exists in Elm 0.18 (try

import Array
import Html exposing (..)

a = Array.fromList ["foo"]
b = Array.fromList ["bar"]
c = Array.append a b

main = div []
  [ text (toString a)
  , text (toString b)
  , text (toString c)
  ]

on elm-lang.org/try, for example), I think it would be a good idea to mention so in the documentation of Array.

[eike]

Since this problem still exists in Elm 0.18 (try

import Array
import Html exposing (..)

a = Array.fromList ["foo"]
b = Array.fromList ["bar"]
c = Array.append a b

main = div []
  [ text (toString a)
  , text (toString b)
  , text (toString c)
  ]

on elm-lang.org/try, for example), I think it would be a good idea to mention so in the documentation of Array.

[ronanyeah]

I think it would be a good idea to mention so in the documentation of Array.

Or at least this comment should be clarified.

[ronanyeah]

I think it would be a good idea to mention so in the documentation of Array.

Or at least this comment should be clarified.