rust/clippy_lints/src/methods/into_iter_on_ref.rs
2024-09-24 11:58:04 +02:00

49 lines
1.5 KiB
Rust

use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::is_trait_method;
use clippy_utils::ty::has_iter_method;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty};
use rustc_span::Span;
use rustc_span::symbol::{Symbol, sym};
use super::INTO_ITER_ON_REF;
pub(super) fn check(
cx: &LateContext<'_>,
expr: &hir::Expr<'_>,
method_span: Span,
method_name: Symbol,
receiver: &hir::Expr<'_>,
) {
let self_ty = cx.typeck_results().expr_ty_adjusted(receiver);
if let ty::Ref(..) = self_ty.kind()
&& method_name == sym::into_iter
&& is_trait_method(cx, expr, sym::IntoIterator)
&& let Some((kind, method_name)) = ty_has_iter_method(cx, self_ty)
{
span_lint_and_sugg(
cx,
INTO_ITER_ON_REF,
method_span,
format!("this `.into_iter()` call is equivalent to `.{method_name}()` and will not consume the `{kind}`",),
"call directly",
method_name.to_string(),
Applicability::MachineApplicable,
);
}
}
fn ty_has_iter_method(cx: &LateContext<'_>, self_ref_ty: Ty<'_>) -> Option<(Symbol, &'static str)> {
has_iter_method(cx, self_ref_ty).map(|ty_name| {
let ty::Ref(_, _, mutbl) = self_ref_ty.kind() else {
unreachable!()
};
let method_name = match mutbl {
hir::Mutability::Not => "iter",
hir::Mutability::Mut => "iter_mut",
};
(ty_name, method_name)
})
}