src/tools/clippy/clippy_lints/src/methods/is_digit_ascii_radix.rs

   1 //! Lint for `c.is_digit(10)`
   2
   3 use super::IS_DIGIT_ASCII_RADIX;
   4 use clippy_utils::msrvs::{self, Msrv};
   5 use clippy_utils::{
   6     consts::constant_full_int, consts::FullInt, diagnostics::span_lint_and_sugg, source::snippet_with_applicability,
   7 };
   8 use rustc_errors::Applicability;
   9 use rustc_hir::Expr;
  10 use rustc_lint::LateContext;
  11
  12 pub(super) fn check<'tcx>(
  13     cx: &LateContext<'tcx>,
  14     expr: &'tcx Expr<'_>,
  15     self_arg: &'tcx Expr<'_>,
  16     radix: &'tcx Expr<'_>,
  17     msrv: &Msrv,
  18 ) {
  19     if !msrv.meets(msrvs::IS_ASCII_DIGIT) {
  20         return;
  21     }
  22
  23     if !cx.typeck_results().expr_ty_adjusted(self_arg).peel_refs().is_char() {
  24         return;
  25     }
  26
  27     if let Some(radix_val) = constant_full_int(cx, cx.typeck_results(), radix) {
  28         let (num, replacement) = match radix_val {
  29             FullInt::S(10) | FullInt::U(10) => (10, "is_ascii_digit"),
  30             FullInt::S(16) | FullInt::U(16) => (16, "is_ascii_hexdigit"),
  31             _ => return,
  32         };
  33         let mut applicability = Applicability::MachineApplicable;
  34
  35         span_lint_and_sugg(
  36             cx,
  37             IS_DIGIT_ASCII_RADIX,
  38             expr.span,
  39             &format!("use of `char::is_digit` with literal radix of {num}"),
  40             "try",
  41             format!(
  42                 "{}.{replacement}()",
  43                 snippet_with_applicability(cx, self_arg.span, "..", &mut applicability)
  44             ),
  45             applicability,
  46         );
  47     }
  48 }