Referencing a variable before assigned compiles correctly, causes runtime JS errors

[gak]

An example:

import Html exposing (text)
import String


main =
    let
        broken =
            if String.isEmpty broken then
                "a"
            else
                "b"
    in
        text broken

I tried a few String operations on broken with similar results.

Also interestingly enough, if broken == "hello" then works without an issue.

The error when running through elm-reactor is:

Runtime.elm:3806
Uncaught TypeError: Cannot read property 'length' of undefined
isEmpty @ Runtime.elm:3806
(anonymous function) @ Runtime.elm:7411
(anonymous function) @ Runtime.elm:7413
(anonymous function) @ Runtime.elm:7448

Runtime.elm:10
Uncaught TypeError: runElmProgram is not a function
(anonymous function) @ Runtime.elm:10

elm-package.json:

{
    "version": "1.0.0",
    "summary": "helpful summary of your project, less than 80 characters",
    "repository": "https://github.com/user/project.git",
    "license": "BSD3",
    "source-directories": [
        "."
    ],
    "exposed-modules": [],
    "dependencies": {
        "elm-lang/core": "4.0.5 <= v < 5.0.0",
        "elm-lang/html": "1.1.0 <= v < 2.0.0"
    },
    "elm-version": "0.17.0 <= v < 0.18.0"
}

Happens in Chrome and Firefox.
ProductName: Mac OS X
ProductVersion: 10.11.5
BuildVersion: 15F34

[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.

[jvoigtlaender]

elm/compiler#873

[jvoigtlaender]

elm/compiler#873

[evancz]

@jvoigtlaender and @lukewestby, it's totally fine to close duplicates like this. Better to tell people to follow the root one.

[evancz]

@jvoigtlaender and @lukewestby, it's totally fine to close duplicates like this. Better to tell people to follow the root one.