clippy_lints/src/methods/bytes_nth.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use clippy_utils::source::snippet_with_applicability;
   3 use clippy_utils::ty::is_type_diagnostic_item;
   4 use rustc_errors::Applicability;
   5 use rustc_hir::Expr;
   6 use rustc_lint::LateContext;
   7 use rustc_span::sym;
   8
   9 use super::BYTES_NTH;
  10
  11 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, recv: &'tcx Expr<'tcx>, n_arg: &'tcx Expr<'tcx>) {
  12     let ty = cx.typeck_results().expr_ty(recv).peel_refs();
  13     let caller_type = if ty.is_str() {
  14         "str"
  15     } else if is_type_diagnostic_item(cx, ty, sym::String) {
  16         "String"
  17     } else {
  18         return;
  19     };
  20     let mut applicability = Applicability::MachineApplicable;
  21     span_lint_and_sugg(
  22         cx,
  23         BYTES_NTH,
  24         expr.span,
  25         &format!("called `.bytes().nth()` on a `{}`", caller_type),
  26         "try",
  27         format!(
  28             "{}.as_bytes().get({})",
  29             snippet_with_applicability(cx, recv.span, "..", &mut applicability),
  30             snippet_with_applicability(cx, n_arg.span, "..", &mut applicability)
  31         ),
  32         applicability,
  33     );
  34 }