103 lines
3.5 KiB
Rust
103 lines
3.5 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_then;
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use clippy_utils::source::{trim_span, walk_span_to_context};
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use clippy_utils::{meets_msrv, msrvs};
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use rustc_ast::ast::{Expr, ExprKind, LitKind, Pat, PatKind, RangeEnd, RangeLimits};
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use rustc_errors::Applicability;
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use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
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use rustc_middle::lint::in_external_macro;
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use rustc_semver::RustcVersion;
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use rustc_session::{declare_tool_lint, impl_lint_pass};
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use rustc_span::Span;
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for ranges which almost include the entire range of letters from 'a' to 'z', but
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/// don't because they're a half open range.
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///
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/// ### Why is this bad?
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/// This (`'a'..'z'`) is almost certainly a typo meant to include all letters.
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///
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/// ### Example
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/// ```rust
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/// let _ = 'a'..'z';
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/// ```
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/// Use instead:
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/// ```rust
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/// let _ = 'a'..='z';
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/// ```
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#[clippy::version = "1.63.0"]
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pub ALMOST_COMPLETE_LETTER_RANGE,
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suspicious,
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"almost complete letter range"
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}
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impl_lint_pass!(AlmostCompleteLetterRange => [ALMOST_COMPLETE_LETTER_RANGE]);
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pub struct AlmostCompleteLetterRange {
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msrv: Option<RustcVersion>,
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}
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impl AlmostCompleteLetterRange {
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pub fn new(msrv: Option<RustcVersion>) -> Self {
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Self { msrv }
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}
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}
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impl EarlyLintPass for AlmostCompleteLetterRange {
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fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) {
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if let ExprKind::Range(Some(start), Some(end), RangeLimits::HalfOpen) = &e.kind {
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let ctxt = e.span.ctxt();
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let sugg = if let Some(start) = walk_span_to_context(start.span, ctxt)
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&& let Some(end) = walk_span_to_context(end.span, ctxt)
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&& meets_msrv(self.msrv, msrvs::RANGE_INCLUSIVE)
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{
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Some((trim_span(cx.sess().source_map(), start.between(end)), "..="))
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} else {
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None
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};
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check_range(cx, e.span, start, end, sugg);
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}
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}
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fn check_pat(&mut self, cx: &EarlyContext<'_>, p: &Pat) {
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if let PatKind::Range(Some(start), Some(end), kind) = &p.kind
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&& matches!(kind.node, RangeEnd::Excluded)
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{
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let sugg = if meets_msrv(self.msrv, msrvs::RANGE_INCLUSIVE) {
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"..="
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} else {
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"..."
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};
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check_range(cx, p.span, start, end, Some((kind.span, sugg)));
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}
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}
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extract_msrv_attr!(EarlyContext);
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}
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fn check_range(cx: &EarlyContext<'_>, span: Span, start: &Expr, end: &Expr, sugg: Option<(Span, &str)>) {
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if let ExprKind::Lit(start_lit) = &start.peel_parens().kind
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&& let ExprKind::Lit(end_lit) = &end.peel_parens().kind
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&& matches!(
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(&start_lit.kind, &end_lit.kind),
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(LitKind::Byte(b'a') | LitKind::Char('a'), LitKind::Byte(b'z') | LitKind::Char('z'))
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| (LitKind::Byte(b'A') | LitKind::Char('A'), LitKind::Byte(b'Z') | LitKind::Char('Z'))
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)
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&& !in_external_macro(cx.sess(), span)
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{
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span_lint_and_then(
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cx,
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ALMOST_COMPLETE_LETTER_RANGE,
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span,
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"almost complete ascii letter range",
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|diag| {
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if let Some((span, sugg)) = sugg {
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diag.span_suggestion(
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span,
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"use an inclusive range",
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sugg,
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Applicability::MaybeIncorrect,
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);
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}
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}
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);
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}
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}
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