Fix or_fun_call for index operator

[camsteffen]

changelog: Fix or_fun_call for index operator

Fixes #6266

[rust-highfive]

r? @flip1995

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[camsteffen]

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.

[camsteffen]

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])?

[flip1995]

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.

[camsteffen]

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

[flip1995]

@bors r+

Thanks!

[bors]

📌 Commit 9cab084 has been approved by flip1995

[bors]

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

[bors]

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