rust/clippy_lints/src/casts/ptr_cast_constness.rs
2023-11-16 19:13:24 +01:00

50 lines
1.5 KiB
Rust

use clippy_config::msrvs::{self, Msrv};
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::sugg::Sugg;
use rustc_errors::Applicability;
use rustc_hir::{Expr, Mutability};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty, TypeAndMut};
use super::PTR_CAST_CONSTNESS;
pub(super) fn check<'tcx>(
cx: &LateContext<'_>,
expr: &Expr<'_>,
cast_expr: &Expr<'_>,
cast_from: Ty<'tcx>,
cast_to: Ty<'tcx>,
msrv: &Msrv,
) {
if msrv.meets(msrvs::POINTER_CAST_CONSTNESS)
&& let ty::RawPtr(TypeAndMut {
mutbl: from_mutbl,
ty: from_ty,
}) = cast_from.kind()
&& let ty::RawPtr(TypeAndMut {
mutbl: to_mutbl,
ty: to_ty,
}) = cast_to.kind()
&& matches!(
(from_mutbl, to_mutbl),
(Mutability::Not, Mutability::Mut) | (Mutability::Mut, Mutability::Not)
)
&& from_ty == to_ty
{
let sugg = Sugg::hir(cx, cast_expr, "_");
let constness = match *to_mutbl {
Mutability::Not => "const",
Mutability::Mut => "mut",
};
span_lint_and_sugg(
cx,
PTR_CAST_CONSTNESS,
expr.span,
"`as` casting between raw pointers while changing only its constness",
&format!("try `pointer::cast_{constness}`, a safer alternative"),
format!("{}.cast_{constness}()", sugg.maybe_par()),
Applicability::MachineApplicable,
);
}
}