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use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::ty::is_type_lang_item;
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::BYTES_COUNT_TO_LEN;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
count_recv: &'tcx hir::Expr<'_>,
bytes_recv: &'tcx hir::Expr<'_>,
) {
if_chain! {
if let Some(bytes_id) = cx.typeck_results().type_dependent_def_id(count_recv.hir_id);
if let Some(impl_id) = cx.tcx.impl_of_method(bytes_id);
if cx.tcx.type_of(impl_id).subst_identity().is_str();
let ty = cx.typeck_results().expr_ty(bytes_recv).peel_refs();
if ty.is_str() || is_type_lang_item(cx, ty, hir::LangItem::String);
then {
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
BYTES_COUNT_TO_LEN,
expr.span,
"using long and hard to read `.bytes().count()`",
"consider calling `.len()` instead",
format!("{}.len()", snippet_with_applicability(cx, bytes_recv.span, "..", &mut applicability)),
applicability
);
}
};
}
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