rust/clippy_lints/src/methods/bytes_nth.rs
2021-10-02 19:38:19 -05:00

35 lines
1.1 KiB
Rust

use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::ty::is_type_diagnostic_item;
use rustc_errors::Applicability;
use rustc_hir::Expr;
use rustc_lint::LateContext;
use rustc_span::sym;
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_diagnostic_item(cx, ty, sym::String) {
"String"
} else {
return;
};
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
BYTES_NTH,
expr.span,
&format!("called `.byte().nth()` on a `{}`", caller_type),
"try",
format!(
"{}.as_bytes().get({})",
snippet_with_applicability(cx, recv.span, "..", &mut applicability),
snippet_with_applicability(cx, n_arg.span, "..", &mut applicability)
),
applicability,
);
}