feat: add ThereOwn linter for "there own" → "their own"

[kimjune01]

Issues

N/A

Description

Adds a ThereOwn linter that catches "there own", "they're own", and "theyre own" and suggests the possessive "their own". Common mistake in informal writing.

How Has This Been Tested?

• Corrects "there own" → "their own"
• Corrects "they're own" → "their own"
• Corrects "theyre own" → "their own"
• Does not flag correct "their own"
• Does not flag "there" without "own"

Checklist

• I have performed a self-review of my own code
• I have added tests to cover my changes

[hippietrail]

Cool. This is one that I'd been looking at recently but had taken the deep dive into. In particular I was worried about a class of false positives I expect to be common: "people there own fancy cars".

I see the current code here does not attempt to avoid flagging these. There's a couple more in my feature request for this that you may or may not have seen but didn't reference: #3276

I'm guessing you made this with an AI. The AI tools I've used never include decent false positive checks until you give them a list of examples. They usually only do the kinds of negative checks I see at the bottom of the mod tests section here.

[hippietrail]

Sorry this needs to avoid some common false positives such as "people there own nice cars".

[hippietrail]

See my comment on how the PR in its current state does not try to avoid flagging false positives that I believe were pointed out in the original issue.

[kimjune01]

Thanks for the review and for linking #3276 — I'd missed the issue, that example list is gold. Two commits after your review (8e79989, plus the new 70c4650) add a context guard that skips the lint when "there" is preceded by a noun or pronoun, since that pattern marks "there" as the adverb and "own" as the verb.

70c4650 adds 8 tests covering your example verbatim ("People there own expensive cars."), the four "there own" positive cases from #3276 (split data, customise effort lvl, modules c files, scripts create connection, silent appstore updates), two "they're own" cases (they're own command, they're own library), and a sentence-initial guard. cargo test there_own passes 16/16; cargo run --bin harper-cli -- lint reports "No lints found" on your example and flags the positive cases. Total harper-core lib suite: 5309 pass, 0 fail.

One thing I left as-is: "they're own" / "theyre own" still always lint, since you described those as "always a possessive error before own" and I couldn't find a counter-example. Happy to add a guard there too if you have a case in mind.

[kimjune01]

Thanks for the concrete example, @hippietrail. The branch already covers that class.

In 70c4650 I added issue_3276_false_positive_expensive_cars in harper-core/src/linting/there_own.rs:

#[test]
fn issue_3276_false_positive_expensive_cars() {
    assert_lint_count("People there own expensive cars.", ThereOwn::default(), 0);
}

CLI confirmation on the branch tip:

$ harper-cli lint /tmp/expensive.txt   # "People there own expensive cars."
No lints found

$ harper-cli lint /tmp/fancy.txt       # "people there own fancy cars"
No lints found

$ harper-cli lint /tmp/split.txt       # "Users can split data on there own topics."
[Word Choice::ThereOwn] (pri 31): Did you mean the possessive `their`?

Heuristic: if the token before there is nominal (noun/pronoun), it parses as the adverb "in that place" and own as the verb, so we suppress. In "split data on there own topics" the preceding token is "on" (preposition), which doesn't license the adverbial reading, so the lint fires.

Happy to add "people there own fancy cars" verbatim as a regression test if you want the exact string pinned.

[hippietrail]

Thanks for addressing everything!

[elijah-potter]

Looks good. Thanks!