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|
use clippy_utils::msrvs::{self, Msrv};
use clippy_utils::{diagnostics::span_lint_and_sugg, higher, in_constant, macros::root_macro_call, source::snippet};
use rustc_ast::ast::RangeLimits;
use rustc_ast::LitKind::{Byte, Char};
use rustc_errors::Applicability;
use rustc_hir::{BorrowKind, Expr, ExprKind, PatKind, RangeEnd};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::{def_id::DefId, sym, Span};
declare_clippy_lint! {
/// ### What it does
/// Suggests to use dedicated built-in methods,
/// `is_ascii_(lowercase|uppercase|digit)` for checking on corresponding ascii range
///
/// ### Why is this bad?
/// Using the built-in functions is more readable and makes it
/// clear that it's not a specific subset of characters, but all
/// ASCII (lowercase|uppercase|digit) characters.
/// ### Example
/// ```rust
/// fn main() {
/// assert!(matches!('x', 'a'..='z'));
/// assert!(matches!(b'X', b'A'..=b'Z'));
/// assert!(matches!('2', '0'..='9'));
/// assert!(matches!('x', 'A'..='Z' | 'a'..='z'));
///
/// ('0'..='9').contains(&'0');
/// ('a'..='z').contains(&'a');
/// ('A'..='Z').contains(&'A');
/// }
/// ```
/// Use instead:
/// ```rust
/// fn main() {
/// assert!('x'.is_ascii_lowercase());
/// assert!(b'X'.is_ascii_uppercase());
/// assert!('2'.is_ascii_digit());
/// assert!('x'.is_ascii_alphabetic());
///
/// '0'.is_ascii_digit();
/// 'a'.is_ascii_lowercase();
/// 'A'.is_ascii_uppercase();
/// }
/// ```
#[clippy::version = "1.66.0"]
pub MANUAL_IS_ASCII_CHECK,
style,
"use dedicated method to check ascii range"
}
impl_lint_pass!(ManualIsAsciiCheck => [MANUAL_IS_ASCII_CHECK]);
pub struct ManualIsAsciiCheck {
msrv: Msrv,
}
impl ManualIsAsciiCheck {
#[must_use]
pub fn new(msrv: Msrv) -> Self {
Self { msrv }
}
}
#[derive(Debug, PartialEq)]
enum CharRange {
/// 'a'..='z' | b'a'..=b'z'
LowerChar,
/// 'A'..='Z' | b'A'..=b'Z'
UpperChar,
/// AsciiLower | AsciiUpper
FullChar,
/// '0..=9'
Digit,
Otherwise,
}
impl<'tcx> LateLintPass<'tcx> for ManualIsAsciiCheck {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if !self.msrv.meets(msrvs::IS_ASCII_DIGIT) {
return;
}
if in_constant(cx, expr.hir_id) && !self.msrv.meets(msrvs::IS_ASCII_DIGIT_CONST) {
return;
}
if let Some(macro_call) = root_macro_call(expr.span)
&& is_matches_macro(cx, macro_call.def_id) {
if let ExprKind::Match(recv, [arm, ..], _) = expr.kind {
let range = check_pat(&arm.pat.kind);
check_is_ascii(cx, macro_call.span, recv, &range);
}
} else if let ExprKind::MethodCall(path, receiver, [arg], ..) = expr.kind
&& path.ident.name == sym!(contains)
&& let Some(higher::Range { start: Some(start), end: Some(end), limits: RangeLimits::Closed })
= higher::Range::hir(receiver) {
let range = check_range(start, end);
if let ExprKind::AddrOf(BorrowKind::Ref, _, e) = arg.kind {
check_is_ascii(cx, expr.span, e, &range);
} else {
check_is_ascii(cx, expr.span, arg, &range);
}
}
}
extract_msrv_attr!(LateContext);
}
fn check_is_ascii(cx: &LateContext<'_>, span: Span, recv: &Expr<'_>, range: &CharRange) {
if let Some(sugg) = match range {
CharRange::UpperChar => Some("is_ascii_uppercase"),
CharRange::LowerChar => Some("is_ascii_lowercase"),
CharRange::FullChar => Some("is_ascii_alphabetic"),
CharRange::Digit => Some("is_ascii_digit"),
CharRange::Otherwise => None,
} {
let default_snip = "..";
// `snippet_with_applicability` may set applicability to `MaybeIncorrect` for
// macro span, so we check applicability manually by comparing `recv` is not default.
let recv = snippet(cx, recv.span, default_snip);
let applicability = if recv == default_snip {
Applicability::HasPlaceholders
} else {
Applicability::MachineApplicable
};
span_lint_and_sugg(
cx,
MANUAL_IS_ASCII_CHECK,
span,
"manual check for common ascii range",
"try",
format!("{recv}.{sugg}()"),
applicability,
);
}
}
fn check_pat(pat_kind: &PatKind<'_>) -> CharRange {
match pat_kind {
PatKind::Or(pats) => {
let ranges = pats.iter().map(|p| check_pat(&p.kind)).collect::<Vec<_>>();
if ranges.len() == 2 && ranges.contains(&CharRange::UpperChar) && ranges.contains(&CharRange::LowerChar) {
CharRange::FullChar
} else {
CharRange::Otherwise
}
},
PatKind::Range(Some(start), Some(end), kind) if *kind == RangeEnd::Included => check_range(start, end),
_ => CharRange::Otherwise,
}
}
fn check_range(start: &Expr<'_>, end: &Expr<'_>) -> CharRange {
if let ExprKind::Lit(start_lit) = &start.kind
&& let ExprKind::Lit(end_lit) = &end.kind {
match (&start_lit.node, &end_lit.node) {
(Char('a'), Char('z')) | (Byte(b'a'), Byte(b'z')) => CharRange::LowerChar,
(Char('A'), Char('Z')) | (Byte(b'A'), Byte(b'Z')) => CharRange::UpperChar,
(Char('0'), Char('9')) | (Byte(b'0'), Byte(b'9')) => CharRange::Digit,
_ => CharRange::Otherwise,
}
} else {
CharRange::Otherwise
}
}
fn is_matches_macro(cx: &LateContext<'_>, macro_def_id: DefId) -> bool {
if let Some(name) = cx.tcx.get_diagnostic_name(macro_def_id) {
return sym::matches_macro == name;
}
false
}
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