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| 1 | +use clippy_utils::diagnostics::span_lint_and_then; |
| 2 | +use clippy_utils::source::{trim_span, walk_span_to_context}; |
| 3 | +use clippy_utils::{meets_msrv, msrvs}; |
| 4 | +use rustc_ast::ast::{Expr, ExprKind, LitKind, Pat, PatKind, RangeEnd, RangeLimits}; |
| 5 | +use rustc_errors::Applicability; |
| 6 | +use rustc_lint::{EarlyContext, EarlyLintPass, LintContext}; |
| 7 | +use rustc_semver::RustcVersion; |
| 8 | +use rustc_session::{declare_tool_lint, impl_lint_pass}; |
| 9 | +use rustc_span::Span; |
| 10 | + |
| 11 | +declare_clippy_lint! { |
| 12 | + /// ### What it does |
| 13 | + /// Checks for ranges which almost include the entire range of letters from 'a' to 'z', but |
| 14 | + /// don't because they're a half open range. |
| 15 | + /// |
| 16 | + /// ### Why is this bad? |
| 17 | + /// This (`'a'..'z'`) is almost certainly a typo meant to include all letters. |
| 18 | + /// |
| 19 | + /// ### Example |
| 20 | + /// ```rust |
| 21 | + /// let _ = 'a'..'z'; |
| 22 | + /// ``` |
| 23 | + /// Use instead: |
| 24 | + /// ```rust |
| 25 | + /// let _ = 'a'..='z'; |
| 26 | + /// ``` |
| 27 | + #[clippy::version = "1.63.0"] |
| 28 | + pub ALMOST_COMPLETE_LETTER_RANGE, |
| 29 | + suspicious, |
| 30 | + "almost complete letter range" |
| 31 | +} |
| 32 | +impl_lint_pass!(AlmostCompleteLetterRange => [ALMOST_COMPLETE_LETTER_RANGE]); |
| 33 | + |
| 34 | +pub struct AlmostCompleteLetterRange { |
| 35 | + msrv: Option<RustcVersion>, |
| 36 | +} |
| 37 | +impl AlmostCompleteLetterRange { |
| 38 | + pub fn new(msrv: Option<RustcVersion>) -> Self { |
| 39 | + Self { msrv } |
| 40 | + } |
| 41 | +} |
| 42 | +impl EarlyLintPass for AlmostCompleteLetterRange { |
| 43 | + fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) { |
| 44 | + if let ExprKind::Range(Some(start), Some(end), RangeLimits::HalfOpen) = &e.kind { |
| 45 | + let ctxt = e.span.ctxt(); |
| 46 | + let sugg = if let Some(start) = walk_span_to_context(start.span, ctxt) |
| 47 | + && let Some(end) = walk_span_to_context(end.span, ctxt) |
| 48 | + && meets_msrv(self.msrv, msrvs::RANGE_INCLUSIVE) |
| 49 | + { |
| 50 | + Some((trim_span(cx.sess().source_map(), start.between(end)), "..=")) |
| 51 | + } else { |
| 52 | + None |
| 53 | + }; |
| 54 | + check_range(cx, e.span, start, end, sugg); |
| 55 | + } |
| 56 | + } |
| 57 | + |
| 58 | + fn check_pat(&mut self, cx: &EarlyContext<'_>, p: &Pat) { |
| 59 | + if let PatKind::Range(Some(start), Some(end), kind) = &p.kind |
| 60 | + && matches!(kind.node, RangeEnd::Excluded) |
| 61 | + { |
| 62 | + let sugg = if meets_msrv(self.msrv, msrvs::RANGE_INCLUSIVE) { |
| 63 | + "..=" |
| 64 | + } else { |
| 65 | + "..." |
| 66 | + }; |
| 67 | + check_range(cx, p.span, start, end, Some((kind.span, sugg))); |
| 68 | + } |
| 69 | + } |
| 70 | + |
| 71 | + extract_msrv_attr!(EarlyContext); |
| 72 | +} |
| 73 | + |
| 74 | +fn check_range(cx: &EarlyContext<'_>, span: Span, start: &Expr, end: &Expr, sugg: Option<(Span, &str)>) { |
| 75 | + if let ExprKind::Lit(start_lit) = &start.peel_parens().kind |
| 76 | + && let ExprKind::Lit(end_lit) = &end.peel_parens().kind |
| 77 | + && matches!( |
| 78 | + (&start_lit.kind, &end_lit.kind), |
| 79 | + (LitKind::Byte(b'a') | LitKind::Char('a'), LitKind::Byte(b'z') | LitKind::Char('z')) |
| 80 | + | (LitKind::Byte(b'A') | LitKind::Char('A'), LitKind::Byte(b'Z') | LitKind::Char('Z')) |
| 81 | + ) |
| 82 | + { |
| 83 | + span_lint_and_then( |
| 84 | + cx, |
| 85 | + ALMOST_COMPLETE_LETTER_RANGE, |
| 86 | + span, |
| 87 | + "almost complete ascii letter range", |
| 88 | + |diag| { |
| 89 | + if let Some((span, sugg)) = sugg { |
| 90 | + diag.span_suggestion( |
| 91 | + span, |
| 92 | + "use an inclusive range", |
| 93 | + sugg.to_owned(), |
| 94 | + Applicability::MaybeIncorrect, |
| 95 | + ); |
| 96 | + } |
| 97 | + } |
| 98 | + ); |
| 99 | + } |
| 100 | +} |
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