1 use clippy_utils::consts::{constant, Constant};
2 use clippy_utils::diagnostics::span_lint_and_sugg;
3 use clippy_utils::is_trait_method;
4 use clippy_utils::source::snippet_with_applicability;
5 use if_chain::if_chain;
6 use rustc_errors::Applicability;
8 use rustc_lint::LateContext;
11 use super::ITER_NTH_ZERO;
13 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
15 if is_trait_method(cx, expr, sym::Iterator);
16 if let Some((Constant::Int(0), _)) = constant(cx, cx.typeck_results(), arg);
18 let mut applicability = Applicability::MachineApplicable;
23 "called `.nth(0)` on a `std::iter::Iterator`, when `.next()` is equivalent",
24 "try calling `.next()` instead of `.nth(0)`",
25 format!("{}.next()", snippet_with_applicability(cx, recv.span, "..", &mut applicability)),