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invalid_null_ptr_usage: fix false positives for std::ptr::slice_from_raw_parts functions #13452

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Merged
merged 3 commits into from
Sep 24, 2024
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invalid_null_ptr_usage: fix false positives for std::ptr::slice_from_raw_parts functions #13452

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f203e1e
Fix false positive invalid null usage warning for `ptr::slice_from_ra…
ljgermain Sep 24, 2024
11363c7
Fix failing UI test
ljgermain Sep 24, 2024
31bbe2c
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ljgermain Sep 24, 2024
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8 changes: 6 additions & 2 deletions clippy_lints/src/ptr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -271,14 +271,18 @@ fn check_invalid_ptr_usage<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
&& let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id()
&& let Some(name) = cx.tcx.get_diagnostic_name(fun_def_id)
{
// TODO: `ptr_slice_from_raw_parts` and its mutable variant should probably still be linted
// conditionally based on how the return value is used, but not universally like the other
// functions since there are valid uses for null slice pointers.
//
// See: https://github.com/rust-lang/rust-clippy/pull/13452/files#r1773772034

// `arg` positions where null would cause U.B.
let arg_indices: &[_] = match name {
sym::ptr_read
| sym::ptr_read_unaligned
| sym::ptr_read_volatile
| sym::ptr_replace
| sym::ptr_slice_from_raw_parts
| sym::ptr_slice_from_raw_parts_mut
| sym::ptr_write
| sym::ptr_write_bytes
| sym::ptr_write_unaligned
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7 changes: 2 additions & 5 deletions tests/ui/invalid_null_ptr_usage.fixed
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Expand Up @@ -24,11 +24,8 @@ fn main() {
let _a: A = std::ptr::read_volatile(core::ptr::NonNull::dangling().as_ptr());

let _a: A = std::ptr::replace(core::ptr::NonNull::dangling().as_ptr(), A);

let _slice: *const [usize] = std::ptr::slice_from_raw_parts(core::ptr::NonNull::dangling().as_ptr(), 0);
let _slice: *const [usize] = std::ptr::slice_from_raw_parts(core::ptr::NonNull::dangling().as_ptr(), 0);

let _slice: *const [usize] = std::ptr::slice_from_raw_parts_mut(core::ptr::NonNull::dangling().as_ptr(), 0);
let _slice: *const [usize] = std::ptr::slice_from_raw_parts(std::ptr::null_mut(), 0); // shouldn't lint
let _slice: *const [usize] = std::ptr::slice_from_raw_parts_mut(std::ptr::null_mut(), 0);

std::ptr::swap::<A>(core::ptr::NonNull::dangling().as_ptr(), &mut A);
std::ptr::swap::<A>(&mut A, core::ptr::NonNull::dangling().as_ptr());
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5 changes: 1 addition & 4 deletions tests/ui/invalid_null_ptr_usage.rs
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Expand Up @@ -24,10 +24,7 @@ fn main() {
let _a: A = std::ptr::read_volatile(std::ptr::null_mut());

let _a: A = std::ptr::replace(std::ptr::null_mut(), A);

let _slice: *const [usize] = std::ptr::slice_from_raw_parts(std::ptr::null(), 0);
let _slice: *const [usize] = std::ptr::slice_from_raw_parts(std::ptr::null_mut(), 0);

let _slice: *const [usize] = std::ptr::slice_from_raw_parts(std::ptr::null_mut(), 0); // shouldn't lint
let _slice: *const [usize] = std::ptr::slice_from_raw_parts_mut(std::ptr::null_mut(), 0);

std::ptr::swap::<A>(std::ptr::null_mut(), &mut A);
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36 changes: 9 additions & 27 deletions tests/ui/invalid_null_ptr_usage.stderr
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Expand Up @@ -85,70 +85,52 @@ LL | let _a: A = std::ptr::replace(std::ptr::null_mut(), A);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:28:69
|
LL | let _slice: *const [usize] = std::ptr::slice_from_raw_parts(std::ptr::null(), 0);
| ^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:29:69
|
LL | let _slice: *const [usize] = std::ptr::slice_from_raw_parts(std::ptr::null_mut(), 0);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:31:73
|
LL | let _slice: *const [usize] = std::ptr::slice_from_raw_parts_mut(std::ptr::null_mut(), 0);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:33:29
--> tests/ui/invalid_null_ptr_usage.rs:30:29
|
LL | std::ptr::swap::<A>(std::ptr::null_mut(), &mut A);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:34:37
--> tests/ui/invalid_null_ptr_usage.rs:31:37
|
LL | std::ptr::swap::<A>(&mut A, std::ptr::null_mut());
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:36:44
--> tests/ui/invalid_null_ptr_usage.rs:33:44
|
LL | std::ptr::swap_nonoverlapping::<A>(std::ptr::null_mut(), &mut A, 0);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:37:52
--> tests/ui/invalid_null_ptr_usage.rs:34:52
|
LL | std::ptr::swap_nonoverlapping::<A>(&mut A, std::ptr::null_mut(), 0);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:39:25
--> tests/ui/invalid_null_ptr_usage.rs:36:25
|
LL | std::ptr::write(std::ptr::null_mut(), A);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:41:35
--> tests/ui/invalid_null_ptr_usage.rs:38:35
|
LL | std::ptr::write_unaligned(std::ptr::null_mut(), A);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:43:34
--> tests/ui/invalid_null_ptr_usage.rs:40:34
|
LL | std::ptr::write_volatile(std::ptr::null_mut(), A);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: pointer must be non-null
--> tests/ui/invalid_null_ptr_usage.rs:45:40
--> tests/ui/invalid_null_ptr_usage.rs:42:40
|
LL | std::ptr::write_bytes::<usize>(std::ptr::null_mut(), 42, 0);
| ^^^^^^^^^^^^^^^^^^^^ help: change this to: `core::ptr::NonNull::dangling().as_ptr()`

error: aborting due to 25 previous errors
error: aborting due to 22 previous errors