Could not find type constructor WebGL.Shader

[Zinggi]

When trying to compile examples for my .obj file loader I ran into a strange issue:

elm-make: Could not find type constructor `WebGL.Shader` while checking types.
elm-make: thread blocked indefinitely in an MVar operation

After some investigations, I managed to reduce it into the following two files:

SSCCE

Needs two files (Main.elm and Shaders.elm)

Main.elm

module Main exposing (..)

import Html exposing (Html)
import Shaders


main =
    Html.text ""

Shaders.elm

module Shaders exposing (..)


frag =
    [glsl|

void main() {
    gl_FragColor = vec4(1.0);
}
|]

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-community/linear-algebra": "1.0.0 <= v < 2.0.0",
        "elm-community/webgl": "2.0.0 <= v <= 3.0.0",
        "elm-lang/core": "5.0.0 <= v < 6.0.0",
        "elm-lang/html": "2.0.0 <= v < 3.0.0"
    },
    "elm-version": "0.18.0 <= v < 0.19.0"
}

Steps to reproduce

Try to compile Main.elm:
elm make Main.elm

Workarounds

Variant 1

Create a new file Test.elm.

module Test exposing (..)

import Html

main = Html.text "test"

compile it:
elm make Test.elm

The previous error vanished, elm make Main.elm now succeeds.

Variant 2

This is more obvious:

Add import WebGL at the top of Shaders.elm

Now compiling works.

OS	browser	Elm version
arch linux	NA	elm-make 0.18 (Elm Platform 0.18.0)

[process-bot]

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

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[marrony]

related #1322