Restrict the cases where ptr_eq triggers (#14526)
`ptr_eq` was recently enhanced to lint on more cases of raw pointers comparison: - lint on all raw pointer comparison, by proposing to use `[core|std]::ptr::eq(lhs, rhs)` instead of `lhs == rhs`; - removing one symetric `as usize` on each size if needed - peeling any level of `as *[const|mut] _` if the remaining expression can still be coerced into the original one (i.e., is a ref or raw pointer to the same type as before) The current change restricts the lint to the cases where at least one level of symetric `as usize`, or any conversion to a raw pointer, could be removed. For example, a direct comparaison of two raw pointers will not trigger the lint anymore. changelog: [`ptr_eq`]: do not lint when comparing two raw pointers directly with no casts involved Fixes rust-lang/rust-clippy#14525
This commit is contained in:
Alex Macleod
Pietro Albini
parent
6e8f95f7ce
commit
287610b489
7 changed files with 60 additions and 100 deletions
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@ -786,9 +786,9 @@ fn check_ptr_eq<'tcx>(
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}
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// Remove one level of usize conversion if any
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let (left, right) = match (expr_as_cast_to_usize(cx, left), expr_as_cast_to_usize(cx, right)) {
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(Some(lhs), Some(rhs)) => (lhs, rhs),
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_ => (left, right),
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let (left, right, usize_peeled) = match (expr_as_cast_to_usize(cx, left), expr_as_cast_to_usize(cx, right)) {
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(Some(lhs), Some(rhs)) => (lhs, rhs, true),
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_ => (left, right, false),
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};
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// This lint concerns raw pointers
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@ -797,7 +797,12 @@ fn check_ptr_eq<'tcx>(
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return;
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}
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let (left_var, right_var) = (peel_raw_casts(cx, left, left_ty), peel_raw_casts(cx, right, right_ty));
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let ((left_var, left_casts_peeled), (right_var, right_casts_peeled)) =
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(peel_raw_casts(cx, left, left_ty), peel_raw_casts(cx, right, right_ty));
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if !(usize_peeled || left_casts_peeled || right_casts_peeled) {
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return;
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}
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let mut app = Applicability::MachineApplicable;
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let left_snip = Sugg::hir_with_context(cx, left_var, expr.span.ctxt(), "_", &mut app);
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@ -830,8 +835,9 @@ fn expr_as_cast_to_usize<'tcx>(cx: &LateContext<'tcx>, cast_expr: &'tcx Expr<'_>
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}
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}
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// Peel raw casts if the remaining expression can be coerced to it
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fn peel_raw_casts<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expr_ty: Ty<'tcx>) -> &'tcx Expr<'tcx> {
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// Peel raw casts if the remaining expression can be coerced to it, and whether casts have been
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// peeled or not.
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fn peel_raw_casts<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expr_ty: Ty<'tcx>) -> (&'tcx Expr<'tcx>, bool) {
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if !expr.span.from_expansion()
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&& let ExprKind::Cast(inner, _) = expr.kind
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&& let ty::RawPtr(target_ty, _) = expr_ty.kind()
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@ -839,8 +845,8 @@ fn peel_raw_casts<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expr_ty:
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&& let ty::RawPtr(inner_target_ty, _) | ty::Ref(_, inner_target_ty, _) = inner_ty.kind()
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&& target_ty == inner_target_ty
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{
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peel_raw_casts(cx, inner, inner_ty)
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(peel_raw_casts(cx, inner, inner_ty).0, true)
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} else {
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expr
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(expr, false)
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}
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}
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@ -23,23 +23,25 @@ fn main() {
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//~^ ptr_eq
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let _ = std::ptr::eq(a, b);
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//~^ ptr_eq
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let _ = std::ptr::eq(a.as_ptr(), b as *const _);
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//~^ ptr_eq
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let _ = std::ptr::eq(a.as_ptr(), b.as_ptr());
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//~^ ptr_eq
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// Do not lint: the rhs conversion is needed
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let _ = a.as_ptr() == b as *const _;
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// Do not lint: we have two raw pointers already
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let _ = a.as_ptr() == b.as_ptr();
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// Do not lint
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let _ = mac!(a, b);
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let _ = another_mac!(a, b);
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let a = &mut [1, 2, 3];
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let b = &mut [1, 2, 3];
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let _ = std::ptr::eq(a.as_mut_ptr(), b as *mut [i32] as *mut _);
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//~^ ptr_eq
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let _ = std::ptr::eq(a.as_mut_ptr(), b.as_mut_ptr());
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//~^ ptr_eq
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// Do not lint: the rhs conversion is needed
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let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _;
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// Do not lint: we have two raw pointers already
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let _ = a.as_mut_ptr() == b.as_mut_ptr();
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let _ = a == b;
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let _ = core::ptr::eq(a, b);
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@ -51,9 +53,9 @@ fn main() {
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let _ = !std::ptr::eq(x, y);
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//~^ ptr_eq
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#[allow(clippy::eq_op)]
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let _issue14337 = std::ptr::eq(main as *const (), main as *const ());
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//~^ ptr_eq
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#[expect(clippy::eq_op)]
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// Do not lint: casts are needed to not change type
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let _issue14337 = main as *const () == main as *const ();
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// Do not peel the content of macros
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let _ = std::ptr::eq(mac!(cast a), mac!(cast b));
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@ -23,23 +23,25 @@ fn main() {
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//~^ ptr_eq
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let _ = a as *const _ == b as *const _;
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//~^ ptr_eq
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// Do not lint: the rhs conversion is needed
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let _ = a.as_ptr() == b as *const _;
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//~^ ptr_eq
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// Do not lint: we have two raw pointers already
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let _ = a.as_ptr() == b.as_ptr();
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//~^ ptr_eq
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// Do not lint
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let _ = mac!(a, b);
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let _ = another_mac!(a, b);
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let a = &mut [1, 2, 3];
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let b = &mut [1, 2, 3];
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// Do not lint: the rhs conversion is needed
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let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _;
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//~^ ptr_eq
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// Do not lint: we have two raw pointers already
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let _ = a.as_mut_ptr() == b.as_mut_ptr();
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//~^ ptr_eq
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let _ = a == b;
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let _ = core::ptr::eq(a, b);
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@ -51,9 +53,9 @@ fn main() {
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let _ = x as *const u32 != y as *mut u32 as *const u32;
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//~^ ptr_eq
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#[allow(clippy::eq_op)]
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#[expect(clippy::eq_op)]
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// Do not lint: casts are needed to not change type
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let _issue14337 = main as *const () == main as *const ();
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//~^ ptr_eq
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// Do not peel the content of macros
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let _ = mac!(cast a) as *const _ == mac!(cast b) as *const _;
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@ -14,52 +14,22 @@ LL | let _ = a as *const _ == b as *const _;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a, b)`
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error: use `std::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq.rs:26:13
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LL | let _ = a.as_ptr() == b as *const _;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a.as_ptr(), b as *const _)`
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error: use `std::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq.rs:28:13
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LL | let _ = a.as_ptr() == b.as_ptr();
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a.as_ptr(), b.as_ptr())`
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error: use `std::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq.rs:39:13
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LL | let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a.as_mut_ptr(), b as *mut [i32] as *mut _)`
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error: use `std::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq.rs:41:13
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LL | let _ = a.as_mut_ptr() == b.as_mut_ptr();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a.as_mut_ptr(), b.as_mut_ptr())`
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error: use `std::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq.rs:48:13
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--> tests/ui/ptr_eq.rs:50:13
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LL | let _ = x as *const u32 == y as *mut u32 as *const u32;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(x, y)`
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error: use `std::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq.rs:51:13
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--> tests/ui/ptr_eq.rs:53:13
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LL | let _ = x as *const u32 != y as *mut u32 as *const u32;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `!std::ptr::eq(x, y)`
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error: use `std::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq.rs:55:23
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LL | let _issue14337 = main as *const () == main as *const ();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(main as *const (), main as *const ())`
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error: use `std::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq.rs:59:13
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--> tests/ui/ptr_eq.rs:61:13
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LL | let _ = mac!(cast a) as *const _ == mac!(cast b) as *const _;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(mac!(cast a), mac!(cast b))`
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error: aborting due to 10 previous errors
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error: aborting due to 5 previous errors
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@ -32,23 +32,25 @@ fn main() {
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//~^ ptr_eq
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let _ = core::ptr::eq(a, b);
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//~^ ptr_eq
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let _ = core::ptr::eq(a.as_ptr(), b as *const _);
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//~^ ptr_eq
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let _ = core::ptr::eq(a.as_ptr(), b.as_ptr());
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//~^ ptr_eq
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// Do not lint: the rhs conversion is needed
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let _ = a.as_ptr() == b as *const _;
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// Do not lint: we have two raw pointers already
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let _ = a.as_ptr() == b.as_ptr();
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// Do not lint
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let _ = mac!(a, b);
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let _ = another_mac!(a, b);
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let a = &mut [1, 2, 3];
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let b = &mut [1, 2, 3];
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let _ = core::ptr::eq(a.as_mut_ptr(), b as *mut [i32] as *mut _);
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//~^ ptr_eq
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let _ = core::ptr::eq(a.as_mut_ptr(), b.as_mut_ptr());
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//~^ ptr_eq
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// Do not lint: the rhs conversion is needed
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let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _;
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// Do not lint: we have two raw pointers already
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let _ = a.as_mut_ptr() == b.as_mut_ptr();
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let _ = a == b;
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let _ = core::ptr::eq(a, b);
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@ -32,23 +32,25 @@ fn main() {
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//~^ ptr_eq
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let _ = a as *const _ == b as *const _;
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//~^ ptr_eq
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// Do not lint: the rhs conversion is needed
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let _ = a.as_ptr() == b as *const _;
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//~^ ptr_eq
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// Do not lint: we have two raw pointers already
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let _ = a.as_ptr() == b.as_ptr();
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//~^ ptr_eq
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// Do not lint
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let _ = mac!(a, b);
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let _ = another_mac!(a, b);
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let a = &mut [1, 2, 3];
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let b = &mut [1, 2, 3];
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// Do not lint: the rhs conversion is needed
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let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _;
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//~^ ptr_eq
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// Do not lint: we have two raw pointers already
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let _ = a.as_mut_ptr() == b.as_mut_ptr();
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//~^ ptr_eq
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let _ = a == b;
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let _ = core::ptr::eq(a, b);
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@ -13,29 +13,5 @@ error: use `core::ptr::eq` when comparing raw pointers
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LL | let _ = a as *const _ == b as *const _;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a, b)`
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error: use `core::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq_no_std.rs:35:13
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LL | let _ = a.as_ptr() == b as *const _;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a.as_ptr(), b as *const _)`
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error: use `core::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq_no_std.rs:37:13
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LL | let _ = a.as_ptr() == b.as_ptr();
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a.as_ptr(), b.as_ptr())`
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error: use `core::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq_no_std.rs:48:13
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LL | let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a.as_mut_ptr(), b as *mut [i32] as *mut _)`
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error: use `core::ptr::eq` when comparing raw pointers
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--> tests/ui/ptr_eq_no_std.rs:50:13
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LL | let _ = a.as_mut_ptr() == b.as_mut_ptr();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a.as_mut_ptr(), b.as_mut_ptr())`
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error: aborting due to 6 previous errors
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error: aborting due to 2 previous errors
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