PistonDevelopers / PistonDevelopers/dyon

Setting early return value fails with `?` using wrong error message

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bug
Dominant language
Rust
Stars
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Forks
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Avg merge
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Merged PRs (30d)
6

Description

fn main() {
    _ := unwrap(start())
}

fn start() -> res {
    return = ok("")
    _ := err("error")?
}

Output:

 --- ERROR --- 
main (source/test.dyon)
start (source/test.dyon)

Requires `->` on function `start`
7,10:     _ := err("error")?
7,10:          ^

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the reproduced snippet from source/test.dyon and inspect the diagnostic path handling the ? expression and early return value. Trace where the "Requires -> on function start" message is selected; done means this case reports the appropriate error for the demonstrated code.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
38/100

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