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| author | Matthias Krüger <matthias.krueger@famsik.de> | 2023-02-20 14:32:55 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-02-20 14:32:55 +0100 |
| commit | 226ce31edde65a0a4b8eff25aab368694e440d51 (patch) | |
| tree | 4cc4a60002008bdea0145c3a784731fd64cc9474 /compiler/rustc_parse/src | |
| parent | 1f5c2b1efd885d730e6cf56f3b5d01c593f20ca6 (diff) | |
| parent | ab4c0dd137f064b9a141d1341c546170b1c7272b (diff) | |
| download | rust-226ce31edde65a0a4b8eff25aab368694e440d51.tar.gz rust-226ce31edde65a0a4b8eff25aab368694e440d51.zip | |
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
Diffstat (limited to 'compiler/rustc_parse/src')
| -rw-r--r-- | compiler/rustc_parse/src/parser/item.rs | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index fd46a1292a8..f164bb330f3 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -19,8 +19,8 @@ use rustc_errors::{ struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic, PResult, StashKey, }; +use rustc_span::edit_distance::edit_distance; use rustc_span::edition::Edition; -use rustc_span::lev_distance::lev_distance; use rustc_span::source_map::{self, Span}; use rustc_span::symbol::{kw, sym, Ident, Symbol}; use rustc_span::DUMMY_SP; @@ -459,7 +459,8 @@ impl<'a> Parser<'a> { // Maybe the user misspelled `macro_rules` (issue #91227) if self.token.is_ident() && path.segments.len() == 1 - && lev_distance("macro_rules", &path.segments[0].ident.to_string(), 3).is_some() + && edit_distance("macro_rules", &path.segments[0].ident.to_string(), 2) + .is_some() { err.span_suggestion( path.span, |