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Auto merge of #11998 - cocodery:fix/issue11762, r=llogiq

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Check whether out of bound when access a known length array with a constant index

fixes [Issue#11762](https://github.com/rust-lang/rust-clippy/issues/11762)

Issue#11762 points that `Array references with known length are not flagged when indexed out of bounds`.

To fix this problem, it is needed to add check for `Expr::Index`. We expand this issue include reference and direct accessing a array.

When we access a array with a constant index `off`, and already know the length `size`, if `off >= size`, these code will throw an error, instead rustc's lint checking them or runtime panic happening.

changelog: [`out_of_bound_indexing`]: Add check for illegal accessing known length array with a constant index
This commit is contained in:
bors 2023-12-22 17:01:17 +00:00
commit e0b25c5a64
10 changed files with 103 additions and 46 deletions
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18
clippy_lints/src/indexing_slicing.rs
View file

@ -170,7 +170,23 @@ impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
return;
}
// Index is a constant uint.
if constant(cx, cx.typeck_results(), index).is_some() {
if let Some(constant) = constant(cx, cx.typeck_results(), index) {
// only `usize` index is legal in rust array index
// leave other type to rustc
if let Constant::Int(off) = constant
&& let ty::Uint(utype) = cx.typeck_results().expr_ty(index).kind()
&& *utype == ty::UintTy::Usize
&& let ty::Array(_, s) = ty.kind()
&& let Some(size) = s.try_eval_target_usize(cx.tcx, cx.param_env)
{
// get constant offset and check whether it is in bounds
let off = usize::try_from(off).unwrap();
let size = usize::try_from(size).unwrap();
if off >= size {
span_lint(cx, OUT_OF_BOUNDS_INDEXING, expr.span, "index is out of bounds");
}
}
// Let rustc's `const_err` lint handle constant `usize` indexing on arrays.
return;
}

3
tests/ui-toml/suppress_lint_in_const/test.rs
View file

@ -7,7 +7,8 @@
unconditional_panic,
clippy::no_effect,
clippy::unnecessary_operation,
clippy::useless_vec
clippy::useless_vec,
clippy::out_of_bounds_indexing
)]
const ARR: [i32; 2] = [1, 2];

18
tests/ui-toml/suppress_lint_in_const/test.stderr
View file

@ -1,17 +1,17 @@
error[E0080]: evaluation of `main::{constant#3}` failed
--> $DIR/test.rs:37:14
--> $DIR/test.rs:38:14
|
LL | const { &ARR[idx4()] }; // Ok, should not produce stderr, since `suppress-restriction-lint-in-const` is set true.
| ^^^^^^^^^^^ index out of bounds: the length is 2 but the index is 4
note: erroneous constant encountered
--> $DIR/test.rs:37:5
--> $DIR/test.rs:38:5
|
LL | const { &ARR[idx4()] }; // Ok, should not produce stderr, since `suppress-restriction-lint-in-const` is set true.
| ^^^^^^^^^^^^^^^^^^^^^^
error: indexing may panic
--> $DIR/test.rs:28:5
--> $DIR/test.rs:29:5
|
LL | x[index];
| ^^^^^^^^
@ -21,7 +21,7 @@ LL | x[index];
= help: to override `-D warnings` add `#[allow(clippy::indexing_slicing)]`
error: indexing may panic
--> $DIR/test.rs:46:5
--> $DIR/test.rs:47:5
|
LL | v[0];
| ^^^^
@ -29,7 +29,7 @@ LL | v[0];
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
--> $DIR/test.rs:47:5
--> $DIR/test.rs:48:5
|
LL | v[10];
| ^^^^^
@ -37,7 +37,7 @@ LL | v[10];
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
--> $DIR/test.rs:48:5
--> $DIR/test.rs:49:5
|
LL | v[1 << 3];
| ^^^^^^^^^
@ -45,7 +45,7 @@ LL | v[1 << 3];
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
--> $DIR/test.rs:54:5
--> $DIR/test.rs:55:5
|
LL | v[N];
| ^^^^
@ -53,7 +53,7 @@ LL | v[N];
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: indexing may panic
--> $DIR/test.rs:55:5
--> $DIR/test.rs:56:5
|
LL | v[M];
| ^^^^
@ -61,7 +61,7 @@ LL | v[M];
= help: consider using `.get(n)` or `.get_mut(n)` instead
error[E0080]: evaluation of constant value failed
--> $DIR/test.rs:15:24
--> $DIR/test.rs:16:24
|
LL | const REF_ERR: &i32 = &ARR[idx4()]; // Ok, let rustc handle const contexts.
| ^^^^^^^^^^^ index out of bounds: the length is 2 but the index is 4

2
tests/ui/crashes/ice-5497.rs
View file

@ -1,4 +1,6 @@
// reduced from rustc issue-69020-assoc-const-arith-overflow.rs
#![allow(clippy::out_of_bounds_indexing)]
pub fn main() {}
pub trait Foo {

2
tests/ui/crashes/ice-5497.stderr
View file

@ -1,5 +1,5 @@
error: this operation will panic at runtime
--> $DIR/ice-5497.rs:9:22
--> $DIR/ice-5497.rs:11:22
|
LL | const OOB: i32 = [1][1] + T::OOB;
| ^^^^^^ index out of bounds: the length is 1 but the index is 1

3
tests/ui/get_unwrap.fixed
View file

@ -2,7 +2,8 @@
unused_mut,
clippy::from_iter_instead_of_collect,
clippy::get_first,
clippy::useless_vec
clippy::useless_vec,
clippy::out_of_bounds_indexing
)]
#![warn(clippy::unwrap_used)]
#![deny(clippy::get_unwrap)]

3
tests/ui/get_unwrap.rs
View file

@ -2,7 +2,8 @@
unused_mut,
clippy::from_iter_instead_of_collect,
clippy::get_first,
clippy::useless_vec
clippy::useless_vec,
clippy::out_of_bounds_indexing
)]
#![warn(clippy::unwrap_used)]
#![deny(clippy::get_unwrap)]

62
tests/ui/get_unwrap.stderr
View file

@ -1,17 +1,17 @@
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:36:17
--> $DIR/get_unwrap.rs:37:17
|
LL | let _ = boxed_slice.get(1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&boxed_slice[1]`
|
note: the lint level is defined here
--> $DIR/get_unwrap.rs:8:9
--> $DIR/get_unwrap.rs:9:9
|
LL | #![deny(clippy::get_unwrap)]
| ^^^^^^^^^^^^^^^^^^
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:36:17
--> $DIR/get_unwrap.rs:37:17
|
LL | let _ = boxed_slice.get(1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -22,13 +22,13 @@ LL | let _ = boxed_slice.get(1).unwrap();
= help: to override `-D warnings` add `#[allow(clippy::unwrap_used)]`
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:37:17
--> $DIR/get_unwrap.rs:38:17
|
LL | let _ = some_slice.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&some_slice[0]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:37:17
--> $DIR/get_unwrap.rs:38:17
|
LL | let _ = some_slice.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -37,13 +37,13 @@ LL | let _ = some_slice.get(0).unwrap();
= help: consider using `expect()` to provide a better panic message
error: called `.get().unwrap()` on a Vec. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:38:17
--> $DIR/get_unwrap.rs:39:17
|
LL | let _ = some_vec.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&some_vec[0]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:38:17
--> $DIR/get_unwrap.rs:39:17
|
LL | let _ = some_vec.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
@ -52,13 +52,13 @@ LL | let _ = some_vec.get(0).unwrap();
= help: consider using `expect()` to provide a better panic message
error: called `.get().unwrap()` on a VecDeque. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:39:17
--> $DIR/get_unwrap.rs:40:17
|
LL | let _ = some_vecdeque.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&some_vecdeque[0]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:39:17
--> $DIR/get_unwrap.rs:40:17
|
LL | let _ = some_vecdeque.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -67,13 +67,13 @@ LL | let _ = some_vecdeque.get(0).unwrap();
= help: consider using `expect()` to provide a better panic message
error: called `.get().unwrap()` on a HashMap. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:40:17
--> $DIR/get_unwrap.rs:41:17
|
LL | let _ = some_hashmap.get(&1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&some_hashmap[&1]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:40:17
--> $DIR/get_unwrap.rs:41:17
|
LL | let _ = some_hashmap.get(&1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -82,13 +82,13 @@ LL | let _ = some_hashmap.get(&1).unwrap();
= help: consider using `expect()` to provide a better panic message
error: called `.get().unwrap()` on a BTreeMap. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:41:17
--> $DIR/get_unwrap.rs:42:17
|
LL | let _ = some_btreemap.get(&1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&some_btreemap[&1]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:41:17
--> $DIR/get_unwrap.rs:42:17
|
LL | let _ = some_btreemap.get(&1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -97,13 +97,13 @@ LL | let _ = some_btreemap.get(&1).unwrap();
= help: consider using `expect()` to provide a better panic message
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:45:21
--> $DIR/get_unwrap.rs:46:21
|
LL | let _: u8 = *boxed_slice.get(1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `boxed_slice[1]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:45:22
--> $DIR/get_unwrap.rs:46:22
|
LL | let _: u8 = *boxed_slice.get(1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -112,13 +112,13 @@ LL | let _: u8 = *boxed_slice.get(1).unwrap();
= help: consider using `expect()` to provide a better panic message
error: called `.get_mut().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:50:9
--> $DIR/get_unwrap.rs:51:9
|
LL | *boxed_slice.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `boxed_slice[0]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:50:10
--> $DIR/get_unwrap.rs:51:10
|
LL | *boxed_slice.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -127,13 +127,13 @@ LL | *boxed_slice.get_mut(0).unwrap() = 1;
= help: consider using `expect()` to provide a better panic message
error: called `.get_mut().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:51:9
--> $DIR/get_unwrap.rs:52:9
|
LL | *some_slice.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `some_slice[0]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:51:10
--> $DIR/get_unwrap.rs:52:10
|
LL | *some_slice.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -142,13 +142,13 @@ LL | *some_slice.get_mut(0).unwrap() = 1;
= help: consider using `expect()` to provide a better panic message
error: called `.get_mut().unwrap()` on a Vec. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:52:9
--> $DIR/get_unwrap.rs:53:9
|
LL | *some_vec.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `some_vec[0]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:52:10
--> $DIR/get_unwrap.rs:53:10
|
LL | *some_vec.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -157,13 +157,13 @@ LL | *some_vec.get_mut(0).unwrap() = 1;
= help: consider using `expect()` to provide a better panic message
error: called `.get_mut().unwrap()` on a VecDeque. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:53:9
--> $DIR/get_unwrap.rs:54:9
|
LL | *some_vecdeque.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `some_vecdeque[0]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:53:10
--> $DIR/get_unwrap.rs:54:10
|
LL | *some_vecdeque.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -172,13 +172,13 @@ LL | *some_vecdeque.get_mut(0).unwrap() = 1;
= help: consider using `expect()` to provide a better panic message
error: called `.get().unwrap()` on a Vec. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:65:17
--> $DIR/get_unwrap.rs:66:17
|
LL | let _ = some_vec.get(0..1).unwrap().to_vec();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `some_vec[0..1]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:65:17
--> $DIR/get_unwrap.rs:66:17
|
LL | let _ = some_vec.get(0..1).unwrap().to_vec();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -187,13 +187,13 @@ LL | let _ = some_vec.get(0..1).unwrap().to_vec();
= help: consider using `expect()` to provide a better panic message
error: called `.get_mut().unwrap()` on a Vec. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:66:17
--> $DIR/get_unwrap.rs:67:17
|
LL | let _ = some_vec.get_mut(0..1).unwrap().to_vec();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `some_vec[0..1]`
error: used `unwrap()` on an `Option` value
--> $DIR/get_unwrap.rs:66:17
--> $DIR/get_unwrap.rs:67:17
|
LL | let _ = some_vec.get_mut(0..1).unwrap().to_vec();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -202,25 +202,25 @@ LL | let _ = some_vec.get_mut(0..1).unwrap().to_vec();
= help: consider using `expect()` to provide a better panic message
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:76:24
--> $DIR/get_unwrap.rs:77:24
|
LL | let _x: &i32 = f.get(1 + 2).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^ help: try: `&f[1 + 2]`
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:79:18
--> $DIR/get_unwrap.rs:80:18
|
LL | let _x = f.get(1 + 2).unwrap().to_string();
| ^^^^^^^^^^^^^^^^^^^^^ help: try: `f[1 + 2]`
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:82:18
--> $DIR/get_unwrap.rs:83:18
|
LL | let _x = f.get(1 + 2).unwrap().abs();
| ^^^^^^^^^^^^^^^^^^^^^ help: try: `f[1 + 2]`
error: called `.get_mut().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:99:33
--> $DIR/get_unwrap.rs:100:33
|
LL | let b = rest.get_mut(linidx(j, k) - linidx(i, k) - 1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&mut rest[linidx(j, k) - linidx(i, k) - 1]`

3
tests/ui/indexing_slicing_index.rs
View file

@ -74,4 +74,7 @@ fn main() {
//~^ ERROR: indexing may panic
v[M];
//~^ ERROR: indexing may panic
let slice = &x;
let _ = x[4];
}

35
tests/ui/indexing_slicing_index.stderr
View file

@ -38,6 +38,21 @@ LL | x[index];
|
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: index is out of bounds
--> $DIR/indexing_slicing_index.rs:32:5
|
LL | x[4];
| ^^^^
|
= note: `-D clippy::out-of-bounds-indexing` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::out_of_bounds_indexing)]`
error: index is out of bounds
--> $DIR/indexing_slicing_index.rs:34:5
|
LL | x[1 << 3];
| ^^^^^^^^^
error: indexing may panic
--> $DIR/indexing_slicing_index.rs:45:14
|
@ -56,6 +71,12 @@ LL | const { &ARR[idx4()] };
= help: consider using `.get(n)` or `.get_mut(n)` instead
= note: the suggestion might not be applicable in constant blocks
error: index is out of bounds
--> $DIR/indexing_slicing_index.rs:55:5
|
LL | y[4];
| ^^^^
error: indexing may panic
--> $DIR/indexing_slicing_index.rs:58:5
|
@ -80,6 +101,12 @@ LL | v[1 << 3];
|
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: index is out of bounds
--> $DIR/indexing_slicing_index.rs:70:5
|
LL | x[N];
| ^^^^
error: indexing may panic
--> $DIR/indexing_slicing_index.rs:73:5
|
@ -96,12 +123,18 @@ LL | v[M];
|
= help: consider using `.get(n)` or `.get_mut(n)` instead
error: index is out of bounds
--> $DIR/indexing_slicing_index.rs:79:13
|
LL | let _ = x[4];
| ^^^^
error[E0080]: evaluation of constant value failed
--> $DIR/indexing_slicing_index.rs:16:24
|
LL | const REF_ERR: &i32 = &ARR[idx4()]; // Ok, let rustc handle const contexts.
| ^^^^^^^^^^^ index out of bounds: the length is 2 but the index is 4
error: aborting due to 12 previous errors
error: aborting due to 17 previous errors
For more information about this error, try `rustc --explain E0080`.