impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+ if cx.tcx.hir().is_inside_const_context(expr.hir_id) {
+ return;
+ }
+
if let ExprKind::Index(array, index) = &expr.kind {
let ty = cx.typeck_results().expr_ty(array).peel_refs();
if let Some(range) = higher::Range::hir(index) {
} else {
// Catchall non-range index, i.e., [n] or [n << m]
if let ty::Array(..) = ty.kind() {
+ // Index is a const block.
+ if let ExprKind::ConstBlock(..) = index.kind {
+ return;
+ }
// Index is a constant uint.
if let Some(..) = constant(cx, cx.typeck_results(), index) {
// Let rustc's `const_err` lint handle constant `usize` indexing on arrays.
+#![feature(inline_const)]
#![warn(clippy::indexing_slicing)]
// We also check the out_of_bounds_indexing lint here, because it lints similar things and
// we want to avoid false positives.
#![warn(clippy::out_of_bounds_indexing)]
-#![allow(clippy::no_effect, clippy::unnecessary_operation)]
+#![allow(const_err, clippy::no_effect, clippy::unnecessary_operation)]
+
+const ARR: [i32; 2] = [1, 2];
+const REF: &i32 = &ARR[idx()]; // Ok, should not produce stderr.
+const REF_ERR: &i32 = &ARR[idx4()]; // Ok, let rustc handle const contexts.
+
+const fn idx() -> usize {
+ 1
+}
+const fn idx4() -> usize {
+ 4
+}
fn main() {
let x = [1, 2, 3, 4];
let index: usize = 1;
x[index];
- x[4]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
- x[1 << 3]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
+ x[4]; // Ok, let rustc's `unconditional_panic` lint handle `usize` indexing on arrays.
+ x[1 << 3]; // Ok, let rustc's `unconditional_panic` lint handle `usize` indexing on arrays.
x[0]; // Ok, should not produce stderr.
x[3]; // Ok, should not produce stderr.
+ x[const { idx() }]; // Ok, should not produce stderr.
+ x[const { idx4() }]; // Ok, let rustc's `unconditional_panic` lint handle `usize` indexing on arrays.
+ const { &ARR[idx()] }; // Ok, should not produce stderr.
+ const { &ARR[idx4()] }; // Ok, let rustc handle const contexts.
let y = &x;
y[0]; // Ok, referencing shouldn't affect this lint. See the issue 6021
const N: usize = 15; // Out of bounds
const M: usize = 3; // In bounds
- x[N]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
+ x[N]; // Ok, let rustc's `unconditional_panic` lint handle `usize` indexing on arrays.
x[M]; // Ok, should not produce stderr.
v[N];
v[M];
+error[E0080]: evaluation of `main::{constant#3}::<&i32>` failed
+ --> $DIR/indexing_slicing_index.rs:31:14
+ |
+LL | const { &ARR[idx4()] }; // Ok, let rustc handle const contexts.
+ | ^^^^^^^^^^^ index out of bounds: the length is 2 but the index is 4
+
+error[E0080]: erroneous constant used
+ --> $DIR/indexing_slicing_index.rs:31:5
+ |
+LL | const { &ARR[idx4()] }; // Ok, let rustc handle const contexts.
+ | ^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
+
error: indexing may panic
- --> $DIR/indexing_slicing_index.rs:10:5
+ --> $DIR/indexing_slicing_index.rs:22:5
|
LL | x[index];
| ^^^^^^^^
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
- --> $DIR/indexing_slicing_index.rs:22:5
+ --> $DIR/indexing_slicing_index.rs:38:5
|
LL | v[0];
| ^^^^
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
- --> $DIR/indexing_slicing_index.rs:23:5
+ --> $DIR/indexing_slicing_index.rs:39:5
|
LL | v[10];
| ^^^^^
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
- --> $DIR/indexing_slicing_index.rs:24:5
+ --> $DIR/indexing_slicing_index.rs:40:5
|
LL | v[1 << 3];
| ^^^^^^^^^
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
- --> $DIR/indexing_slicing_index.rs:30:5
+ --> $DIR/indexing_slicing_index.rs:46:5
|
LL | v[N];
| ^^^^
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
- --> $DIR/indexing_slicing_index.rs:31:5
+ --> $DIR/indexing_slicing_index.rs:47:5
|
LL | v[M];
| ^^^^
|
= help: consider using `.get(n)` or `.get_mut(n)` instead
-error: aborting due to 6 previous errors
+error: aborting due to 8 previous errors
+For more information about this error, try `rustc --explain E0080`.