Panic: LIR lowering expected layouts to match or differ by an explicit Box edge

[niclas-ahden]

roc build panics on valid code (roc check is clean) with:

postcheck invariant violated: LIR lowering expected layouts to match or
differ by an explicit Box edge

We need three files to reproduce:

Foo.roc:

Foo := [
    Node(List(Foo.Qux), List(Foo)),
].{
    Qux := [Wrap(Box(Str -> Str))]

    wrap : { items : List(Foo) } -> Foo
    wrap = |args|
        Node([], args.items)
}

Bar.roc:

import Foo exposing [Foo]

Bar := [].{
    build : List(Str) -> Foo
    build = |model|
        Foo.wrap(
            {
                items: [
                    Foo.Node(
                        [Foo.Qux.Wrap(Box.box(|_v| "made"))],
                        model.map(|_s| Foo.Node([], [])),
                    ),
                ],
            },
        )
}

main.roc (on the test/fx platform):

app [main!] { pf: platform "../platform/main.roc" }

import pf.Stdout
import Bar

main! = || {
    _foo = Bar.build([])
    Stdout.line!("done")
}

Tested on NixOS, x86, Roc 317e608ca2.

[rtfeldman]

No longer reproduces.