Replace expr_visitor with for_each_expr

[Jarcho]

This is a minor change which uses ControlFlow rather than a boolean. This also runs the visitor rather than returning the visitor, which results in a small readability win as well.

changelog: None

[rust-highfive]

r? @giraffate

(rust-highfive has picked a reviewer for you, use r? to override)

[bors]

☔ The latest upstream changes (presumably #8779) made this pull request unmergeable. Please resolve the merge conflicts.

[Jarcho]

Great. The compiler broke... Looks like rust-lang/rust#99866.

[flip1995]

LGTM. Will merge after the next sync.

[bors]

☔ The latest upstream changes (presumably #9447) made this pull request unmergeable. Please resolve the merge conflicts.

[flip1995]

Huh. Forgot about it. Can you rebase and then r+ yourself, if CI passes?

[Jarcho]

Looks like this is still broken. rust-lang/rust#101410 is a possible fix.

[bors]

☔ The latest upstream changes (presumably #9458) made this pull request unmergeable. Please resolve the merge conflicts.

[Jarcho]

Narrowed the issue down to something with let-chains mir opt levels. Pretty good match with rust-lang/#99852. Just added a workaround until the rustc bug is fixed.

@bors r+

[bors]

📌 Commit 26bb366 has been approved by Jarcho

It is now in the queue for this repository.

[bors]

⌛ Testing commit 26bb366 with merge 2be6c4a...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: Jarcho
Pushing 2be6c4a to master...