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]

:umbrella: 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]

:umbrella: 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]

:umbrella: 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]

:pushpin: Commit 26bb36636ca9d71958055e05053946d22fcfbdbb has been approved by Jarcho

It is now in the queue for this repository.

[bors]

:hourglass: Testing commit 26bb36636ca9d71958055e05053946d22fcfbdbb with merge 2be6c4ae5b075028a6c61ba75daaf22fb7921c85...

[bors]

:sunny: Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test Approved by: Jarcho Pushing 2be6c4ae5b075028a6c61ba75daaf22fb7921c85 to master...