Compiler Hangs on "applyl" type function

[bengolds]

Wasn't obvious to me whether or not this was covered in Issue 1240. The following code causes the compiler to spin up to 100% resource utilization:

applyl : List (a -> a) -> a -> a
applyl fns start =
    List.foldl (\acc fn -> fn acc) start fns

Elm 0.18 on OSX and Ubuntu

[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.

[evancz]

With the latest version, the error is like this:

-- INFINITE TYPE -------------------------------------------------------

I am inferring a weird self-referential type for the 2nd argument to function
`foldl`:

133|     List.foldl (\acc fn -> fn acc) start fns
                                        ^^^^^
Here is my best effort at writing down the type. You will see ∞ for parts of the
type that repeat something already printed out infinitely.

    a -> ∞

Usually staring at the type is not so helpful in these cases, so definitely read
the debugging hints for ideas on how to figure this out:
<https://github.com/elm-lang/elm-compiler/blob/0.19.0/hints/infinite-type.md>

Thanks for the report!