feat: for loop to while let assist #19271
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
rustbot
added
the
S-waiting-on-review
vishruth-thimmaiah
force-pushed
the
for_loop_to_while_let
branch
2 times, most recently
from
691550b to
e4c24a8
Compare
DropDemBits
suggested changes
Mar 12, 2025
Comment on lines
28
to
34
| // fn main() { | ||
| // let x = vec![1, 2, 3]; | ||
| // while let Some(v) = x.into_iter().next() { | ||
| // let y = v * 2; | ||
| // }; | ||
| // } |
Contributor
There was a problem hiding this comment.
Hm, I don't think this is the right conversion for that for-loop.
This will create a new iterator for every while-loop iteration, but as the into_iterator takes ownership of the Vec it'll fail to compile.
Generally, I think the correct way to do the conversion is to instead check if the iterable expression implements IntoIterator and then generate a let statement to hold the iterator. This is closer to the actual desugaring of a for-loop, and by extension would also handle the (1..2), &x, and &mut x cases. (though it'd be nice to keep the &x -> x.iter() and &mut x -> x.iter_mut() transformations if available).
DropDemBits
added
S-waiting-on-author
vishruth-thimmaiah
force-pushed
the
for_loop_to_while_let
branch
from
e4c24a8 to
53f3e6f
Compare
DropDemBits
added
S-waiting-on-review
DropDemBits
approved these changes
Mar 14, 2025
Contributor
DropDemBits
left a comment
DropDemBits
left a comment
There was a problem hiding this comment.
Looks good to me, thanks!
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Closes: #19256
adds an assist that converts a for loop into a while let loop.