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rewrite ... to ..= as an idiom lint for Rust 2018 edition #51043
Description
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Do we have an existing lint for this?
If we hope to someday get rid of
...in patterns (the current description of #28237 describes it as "(silently) deprecated"), wouldn't we want a future-incompatible lint rather than an idiom lint? (...in expressions is already illegal.)Reacted by scottmcmOne remaining issue of
a..=bpattern is #48501. When stabilizinga..=b, to avoid the confusing interpretation of&a...b, in the following example:fn main() { match &5 { &3...6 => {} _ => {} } }
if we just
s/.../..=/gthe code will error witherror: the range pattern here has ambiguous interpretation --> src/main.rs:3:10 | 3 | &3..=6 => {} | ^^^^^ help: add parentheses to clarify the precedence: `(3 ..=6)`Note that
pattern_parentheses(#48500) is still unstable 🙃. However, given that default binding modes (#42640) is already stable, an even more idiomatic fix would probably befn main() { match &5 { 3..=6 => {} // no &, no (), no whatever _ => {} } }
Reacted by Mateusz Mikuła and JubileeReacted by scottmcm and JubileeIf we hope to someday get rid of ... in patterns (the current description of #28237 describes it as "(silently) deprecated"), wouldn't we want a future-incompatible lint rather than an idiom lint? (... in expressions is already illegal.)
I classified it as an idiom lint because the code will not cause a hard error in the new edition, even if it is frowned upon.
Reacted by James Beau16 remaining items
visited for T-compiler triage. It seems like it was blocked on stabilization of the pattern-parentheses feature. So what are the next steps, and who wants to own this?
Removing from the milestone, as idiom lints are not part of the Rust 2018 release.
Reacted by James Beau- added a commit that references this issue
on Sep 14, 2019
Current status
Implemented in #51149 but currently not marked as automatically applicable due to this issue which is explained below