Stream: announcements

Topic: Breaking change with `import Foo exposing [Foo]`

Aurélien Geron (Oct 04 2026 at 21:49):

Since the 2026-10-02 nightly, the following code causes a compilation error:

import Foo exposing [Foo]

You must now write this instead:

import Foo

The error is pretty clear:

── ✗ redundant expose ───────────────────────────────────── break.roc:1:22

Redundantly exposing Foo when importing Foo.

import Foo exposing [Foo]
                     ^^^

The type Foo is automatically exposed when importing a type module.

Remove Foo from the exposing clause.

Several platforms and packages need to be updated. I've submitted PRs for these:

• basic-cli: https://github.com/roc-lang/basic-cli/pull/504
• basic-webserver: https://github.com/roc-lang/basic-webserver/pull/238

Side-note: explicitly making a union open (using ..) in an output position now triggers a warning, since unions are automatically open in output positions now. So instead of writing U64 -> Try(U64, [A, B, ..]), you must write U64 -> Try(U64, [A, B]). The good news is that roc fmt will fix that for you (unfortunately, it doesn't fix the import error described above).

Luke Boswell (Oct 04 2026 at 21:54):

Thank you, I forgot I merged that and didn't connect the dots that this would be a breaking change

Last updated: Oct 15 2026 at 17:56 UTC