rust/compiler/rustc_lint
Matthias Krüger 226ce31edd
Rollup merge of #108200 - jhpratt:restricted-damerau-levenshtein-distance, r=tmiasko
Use restricted Damerau-Levenshtein distance for diagnostics

This replaces the existing Levenshtein algorithm with the Damerau-Levenshtein algorithm. This means that "ab" to "ba" is one change (a transposition) instead of two (a deletion and insertion). More specifically, this is a _restricted_ implementation, in that "ca" to "abc" cannot be performed as "ca" → "ac" → "abc", as there is an insertion in the middle of a transposition. I believe that errors like that are sufficiently rare that it's not worth taking into account.

This was first brought up [on IRLO](https://internals.rust-lang.org/t/18227) when it was noticed that the diagnostic for `prinltn!` (transposed L and T) was `print!` and not `println!`. Only a single existing UI test was effected, with the result being an objective improvement.

~~I have left the method name and various other references to the Levenshtein algorithm untouched, as the exact manner in which the edit distance is calculated should not be relevant to the caller.~~

r? ``@estebank``

``@rustbot`` label +A-diagnostics +C-enhancement
2023-02-20 14:32:55 +01:00
..
src Rollup merge of #108200 - jhpratt:restricted-damerau-levenshtein-distance, r=tmiasko 2023-02-20 14:32:55 +01:00
Cargo.toml Update unicode-rs crates to Unicode 15 2022-09-17 01:55:56 +08:00