1 use clippy_utils::diagnostics::span_lint_and_sugg;
2 use clippy_utils::source::snippet_with_applicability;
3 use clippy_utils::ty::is_type_lang_item;
4 use if_chain::if_chain;
5 use rustc_errors::Applicability;
7 use rustc_lint::LateContext;
9 use super::BYTES_COUNT_TO_LEN;
11 pub(super) fn check<'tcx>(
12 cx: &LateContext<'tcx>,
13 expr: &'tcx hir::Expr<'_>,
14 count_recv: &'tcx hir::Expr<'_>,
15 bytes_recv: &'tcx hir::Expr<'_>,
18 if let Some(bytes_id) = cx.typeck_results().type_dependent_def_id(count_recv.hir_id);
19 if let Some(impl_id) = cx.tcx.impl_of_method(bytes_id);
20 if cx.tcx.type_of(impl_id).is_str();
21 let ty = cx.typeck_results().expr_ty(bytes_recv).peel_refs();
22 if ty.is_str() || is_type_lang_item(cx, ty, hir::LangItem::String);
24 let mut applicability = Applicability::MachineApplicable;
29 "using long and hard to read `.bytes().count()`",
30 "consider calling `.len()` instead",
31 format!("{}.len()", snippet_with_applicability(cx, bytes_recv.span, "..", &mut applicability)),