rust/clippy_lints/src/methods/iter_count.rs

49 lines
1.6 KiB
Rust

use super::utils::derefs_to_slice;
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::ITER_COUNT;
pub(crate) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, recv: &'tcx Expr<'tcx>, iter_method: &str) {
let ty = cx.typeck_results().expr_ty(recv);
let caller_type = if derefs_to_slice(cx, recv, ty).is_some() {
"slice"
} else if is_type_diagnostic_item(cx, ty, sym::Vec) {
"Vec"
} else if is_type_diagnostic_item(cx, ty, sym::VecDeque) {
"VecDeque"
} else if is_type_diagnostic_item(cx, ty, sym::HashSet) {
"HashSet"
} else if is_type_diagnostic_item(cx, ty, sym::HashMap) {
"HashMap"
} else if is_type_diagnostic_item(cx, ty, sym::BTreeMap) {
"BTreeMap"
} else if is_type_diagnostic_item(cx, ty, sym::BTreeSet) {
"BTreeSet"
} else if is_type_diagnostic_item(cx, ty, sym::LinkedList) {
"LinkedList"
} else if is_type_diagnostic_item(cx, ty, sym::BinaryHeap) {
"BinaryHeap"
} else {
return;
};
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
ITER_COUNT,
expr.span,
format!("called `.{iter_method}().count()` on a `{caller_type}`"),
"try",
format!(
"{}.len()",
snippet_with_applicability(cx, recv.span, "..", &mut applicability),
),
applicability,
);
}