1 use super::utils::derefs_to_slice;
2 use crate::methods::iter_nth_zero;
3 use clippy_utils::diagnostics::span_lint_and_help;
4 use clippy_utils::ty::is_type_diagnostic_item;
6 use rustc_lint::LateContext;
7 use rustc_span::symbol::sym;
11 pub(super) fn check<'tcx>(
12 cx: &LateContext<'tcx>,
14 iter_recv: &'tcx hir::Expr<'tcx>,
15 nth_recv: &hir::Expr<'_>,
16 nth_arg: &hir::Expr<'_>,
19 let mut_str = if is_mut { "_mut" } else { "" };
20 let caller_type = if derefs_to_slice(cx, iter_recv, cx.typeck_results().expr_ty(iter_recv)).is_some() {
22 } else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(iter_recv), sym::vec_type) {
24 } else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(iter_recv), sym::vecdeque_type) {
27 iter_nth_zero::check(cx, expr, nth_recv, nth_arg);
28 return; // caller is not a type that we want to lint
35 &format!("called `.iter{0}().nth()` on a {1}", mut_str, caller_type),
37 &format!("calling `.get{}()` is both faster and more readable", mut_str),