| use clippy_utils::diagnostics::span_lint_and_sugg; |
| use clippy_utils::source::snippet_with_applicability; |
| use clippy_utils::ty::is_type_lang_item; |
| use rustc_errors::Applicability; |
| use rustc_hir::{Expr, LangItem}; |
| use rustc_lint::LateContext; |
| |
| use crate::methods::method_call; |
| |
| use super::BYTES_NTH; |
| |
| pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, recv: &'tcx Expr<'tcx>, n_arg: &'tcx Expr<'tcx>) { |
| let ty = cx.typeck_results().expr_ty(recv).peel_refs(); |
| let caller_type = if ty.is_str() { |
| "str" |
| } else if is_type_lang_item(cx, ty, LangItem::String) { |
| "String" |
| } else { |
| return; |
| }; |
| |
| let mut applicability = Applicability::MachineApplicable; |
| let receiver = snippet_with_applicability(cx, recv.span, "..", &mut applicability); |
| let n = snippet_with_applicability(cx, n_arg.span, "..", &mut applicability); |
| |
| if let Some(parent) = clippy_utils::get_parent_expr(cx, expr) |
| && let Some((name, _, _, _, _)) = method_call(parent) |
| && name == "unwrap" |
| { |
| span_lint_and_sugg( |
| cx, |
| BYTES_NTH, |
| parent.span, |
| &format!("called `.bytes().nth().unwrap()` on a `{caller_type}`"), |
| "try", |
| format!("{receiver}.as_bytes()[{n}]",), |
| applicability, |
| ); |
| } else { |
| span_lint_and_sugg( |
| cx, |
| BYTES_NTH, |
| expr.span, |
| &format!("called `.bytes().nth()` on a `{caller_type}`"), |
| "try", |
| format!("{receiver}.as_bytes().get({n}).copied()"), |
| applicability, |
| ); |
| }; |
| } |