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Oops. The fix for references (e.g. opt.map_or(&foo())) doesn't work due to lifetimes. I'll remove that part for this PR.

Need to resolve the question of including slices at #6267.

Also, I think I should amend this to not include opt.map_or(array[const_expr])?

Need to resolve the question of including slices at #6267.

I don't think we should lint on indexing slices, arrays or vecs, since those operations are O(1), even with bounds checks, while indexing into hashmaps can be way more involved.

Okay, now it will only lint when indexing HashMap or BTreeMap.

@bors r+

Thanks!

📌 Commit 9cab084 has been approved by flip1995

⌛ Testing commit 9cab084 with merge 2067a01...

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: flip1995
Pushing 2067a01 to master...