Leaving type parameters out of type annotation compiles when it shouldn't

[naddeoa]

We were talking about some weirdness in the general chat today and user alon came up with a simple example to showcase it. The following code compiles.

type SomeUnion a b c
    = SomeType a
    | SomeOtherType b c


myFunction : SomeUnion a -> String
myFunction atype =
    "hmm but why?"

SomeUnion takes three type parameters but only one is supplied. No one will be able to call this function because no one can make a SomeUnion a obviously, so I suppose the damage is as minimal as it gets.

This was tested on Elm 0.18.0 on Ubuntu 16.04.

[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.

[mgold]

Seems to be part of "no kind checking", #1373. Thanks for the report!

[rtfeldman]

Added to the No Kind Checking section of #1373 - thanks again!

[evancz]

In the development build, I am getting:

- TOO FEW ARGS ------------------------------------------------------- temp.elm

The `SomeUnion` type was given 1 argument:

14| myFunction : SomeUnion a -> String
                 ^^^^^^^^^^^
But it needs 3 arguments. What is missing? Are some parentheses misplaced?

Because we now rule this out in the canonicalization phase. Thanks for the report!

[naddeoa]

Nice, thank a lot