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::{
   5     consts::constant_full_int, consts::FullInt, diagnostics::span_lint_and_sugg, meets_msrv, msrvs,
   6     source::snippet_with_applicability,
   7 };
   8 use rustc_errors::Applicability;
   9 use rustc_hir::Expr;
  10 use rustc_lint::LateContext;
  11 use rustc_semver::RustcVersion;
  12
  13 pub(super) fn check<'tcx>(
  14     cx: &LateContext<'tcx>,
  15     expr: &'tcx Expr<'_>,
  16     self_arg: &'tcx Expr<'_>,
  17     radix: &'tcx Expr<'_>,
  18     msrv: Option<&RustcVersion>,
  19 ) {
  20     if !meets_msrv(msrv, &msrvs::IS_ASCII_DIGIT) {
  21         return;
  22     }
  23
  24     if !cx.typeck_results().expr_ty_adjusted(self_arg).peel_refs().is_char() {
  25         return;
  26     }
  27
  28     if let Some(radix_val) = constant_full_int(cx, cx.typeck_results(), radix) {
  29         let (num, replacement) = match radix_val {
  30             FullInt::S(10) | FullInt::U(10) => (10, "is_ascii_digit"),
  31             FullInt::S(16) | FullInt::U(16) => (16, "is_ascii_hexdigit"),
  32             _ => return,
  33         };
  34         let mut applicability = Applicability::MachineApplicable;
  35
  36         span_lint_and_sugg(
  37             cx,
  38             IS_DIGIT_ASCII_RADIX,
  39             expr.span,
  40             &format!("use of `char::is_digit` with literal radix of {}", num),
  41             "try",
  42             format!(
  43                 "{}.{}()",
  44                 snippet_with_applicability(cx, self_arg.span, "..", &mut applicability),
  45                 replacement
  46             ),
  47             applicability,
  48         );
  49     }
  50 }