Stream: bugs

Topic: Error using exposed effectful function from module in folder

George (Aug 21 2026 at 17:56):

Given this example:

# in ./main.roc

app [main!] { pf: platform "https://github.com/roc-lang/basic-cli/releases/download/0.22.0/F1JVZPYfWP71s8vk6tHcV1Qx1Ef6CZkwswGoCn8VHZmL.tar.zst" }

import Folder/Foo exposing [log!]

main! = |_args| {
  log!("Hello World!")?
  Ok({})
}

and

# in ./Folder/Foo.roc

import pf.Stdout

Foo := {}.{
    log! = |message| Stdout.line!(message)
}

I get this this error:

│ VALUE NOT EXPOSED ├─ The value log! is not exposed by the module Folder/Foo.
 │  import Folder/Foo exposing [log!]

and

│ NAME NOT IN SCOPE ├─ Nothing is named log! in this scope.
│  log!("Hello World!")?

This seems like a bug, and the error does not occur if I rename the function from log! to log (but I get a warning that an effectful function should end with !).

This happens on the latest roc (I just pulled and rebuilt from source).

Richard Feldman (Aug 21 2026 at 19:09):

@George thanks for reporting! Would you mind opening a GitHub issue for that?

George (Aug 21 2026 at 19:10):

@Richard Feldman will do!
Just making sure: should I report future bugs I encounter here again, or just open them directly on github?

Richard Feldman (Aug 21 2026 at 19:11):

GitHub is better these days...we used to mostly use Zulip for that, but now that more people are using the language, gh is better :smile:

George (Aug 21 2026 at 19:15):

created https://github.com/roc-lang/roc/issues/10897

Last updated: Sep 03 2026 at 15:16 UTC