"Cannot find variable `X.T`. No module called X has been imported." when X has been imported but not exposing type correctly

[stoft]

I get the following error even though I have imported SubTypes:

Detected errors in 1 module.
-- NAMING ERROR ------------------------------------------------------- Main.elm

Cannot find variable `SubTypes.MyType`.

15|             SubType SubTypes.MyType
                        ^^^^^^^^^^^^^^^
No module called `SubTypes` has been imported. 

The actual error is that the SubTypes module is not exposing its type correctly: module SubTypes exposing (Type) when it should be module SubTypes exposing (Type(..)). A more correct error message would be that SubTypes does not expose MyType.

SSCCE:

module SubTypes exposing (Type)

type Type
    = MyType

module Main exposing (main)

import Html
import SubTypes

type SuperType
    = NoOp
    | SubType SubTypes.Type

main =
    let
        t =
            SubType SubTypes.MyType
    in
        Html.text "MyType found!"

[isti115]

This was real confusing, because it happened to me while using an "as" alias in the import and thought that it was the cause of the bug, but I'm glad I found this issue before reporting it as a new one.