From cbfe1f5f587c314ad64c57a7c7d2b38cdb3d3b7e Mon Sep 17 00:00:00 2001 From: Samuel Tardieu Date: Thu, 3 Apr 2025 00:02:44 +0200 Subject: [PATCH] Restrict the cases where `ptr_eq` triggers `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. --- clippy_lints/src/ptr.rs | 22 ++++++++++++-------- tests/ui/ptr_eq.fixed | 26 +++++++++++++----------- tests/ui/ptr_eq.rs | 16 ++++++++------- tests/ui/ptr_eq.stderr | 38 ++++------------------------------- tests/ui/ptr_eq_no_std.fixed | 20 +++++++++--------- tests/ui/ptr_eq_no_std.rs | 12 ++++++----- tests/ui/ptr_eq_no_std.stderr | 26 +----------------------- 7 files changed, 60 insertions(+), 100 deletions(-) diff --git a/clippy_lints/src/ptr.rs b/clippy_lints/src/ptr.rs index 5fb4d3a837b1..b76e54c382db 100644 --- a/clippy_lints/src/ptr.rs +++ b/clippy_lints/src/ptr.rs @@ -715,9 +715,9 @@ fn check_ptr_eq<'tcx>( } // Remove one level of usize conversion if any - let (left, right) = match (expr_as_cast_to_usize(cx, left), expr_as_cast_to_usize(cx, right)) { - (Some(lhs), Some(rhs)) => (lhs, rhs), - _ => (left, right), + let (left, right, usize_peeled) = match (expr_as_cast_to_usize(cx, left), expr_as_cast_to_usize(cx, right)) { + (Some(lhs), Some(rhs)) => (lhs, rhs, true), + _ => (left, right, false), }; // This lint concerns raw pointers @@ -726,7 +726,12 @@ fn check_ptr_eq<'tcx>( return; } - let (left_var, right_var) = (peel_raw_casts(cx, left, left_ty), peel_raw_casts(cx, right, right_ty)); + let ((left_var, left_casts_peeled), (right_var, right_casts_peeled)) = + (peel_raw_casts(cx, left, left_ty), peel_raw_casts(cx, right, right_ty)); + + if !(usize_peeled || left_casts_peeled || right_casts_peeled) { + return; + } let mut app = Applicability::MachineApplicable; let left_snip = Sugg::hir_with_context(cx, left_var, expr.span.ctxt(), "_", &mut app); @@ -759,8 +764,9 @@ fn expr_as_cast_to_usize<'tcx>(cx: &LateContext<'tcx>, cast_expr: &'tcx Expr<'_> } } -// Peel raw casts if the remaining expression can be coerced to it -fn peel_raw_casts<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expr_ty: Ty<'tcx>) -> &'tcx Expr<'tcx> { +// Peel raw casts if the remaining expression can be coerced to it, and whether casts have been +// peeled or not. +fn peel_raw_casts<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expr_ty: Ty<'tcx>) -> (&'tcx Expr<'tcx>, bool) { if !expr.span.from_expansion() && let ExprKind::Cast(inner, _) = expr.kind && let ty::RawPtr(target_ty, _) = expr_ty.kind() @@ -768,8 +774,8 @@ fn peel_raw_casts<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expr_ty: && let ty::RawPtr(inner_target_ty, _) | ty::Ref(_, inner_target_ty, _) = inner_ty.kind() && target_ty == inner_target_ty { - peel_raw_casts(cx, inner, inner_ty) + (peel_raw_casts(cx, inner, inner_ty).0, true) } else { - expr + (expr, false) } } diff --git a/tests/ui/ptr_eq.fixed b/tests/ui/ptr_eq.fixed index 484ff3073239..f0150e6784b4 100644 --- a/tests/ui/ptr_eq.fixed +++ b/tests/ui/ptr_eq.fixed @@ -23,23 +23,25 @@ fn main() { //~^ ptr_eq let _ = std::ptr::eq(a, b); //~^ ptr_eq - let _ = std::ptr::eq(a.as_ptr(), b as *const _); - //~^ ptr_eq - let _ = std::ptr::eq(a.as_ptr(), b.as_ptr()); - //~^ ptr_eq - // Do not lint + // Do not lint: the rhs conversion is needed + let _ = a.as_ptr() == b as *const _; + // Do not lint: we have two raw pointers already + let _ = a.as_ptr() == b.as_ptr(); + + // Do not lint let _ = mac!(a, b); let _ = another_mac!(a, b); let a = &mut [1, 2, 3]; let b = &mut [1, 2, 3]; - let _ = std::ptr::eq(a.as_mut_ptr(), b as *mut [i32] as *mut _); - //~^ ptr_eq - let _ = std::ptr::eq(a.as_mut_ptr(), b.as_mut_ptr()); - //~^ ptr_eq + // Do not lint: the rhs conversion is needed + let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _; + + // Do not lint: we have two raw pointers already + let _ = a.as_mut_ptr() == b.as_mut_ptr(); let _ = a == b; let _ = core::ptr::eq(a, b); @@ -51,9 +53,9 @@ fn main() { let _ = !std::ptr::eq(x, y); //~^ ptr_eq - #[allow(clippy::eq_op)] - let _issue14337 = std::ptr::eq(main as *const (), main as *const ()); - //~^ ptr_eq + #[expect(clippy::eq_op)] + // Do not lint: casts are needed to not change type + let _issue14337 = main as *const () == main as *const (); // Do not peel the content of macros let _ = std::ptr::eq(mac!(cast a), mac!(cast b)); diff --git a/tests/ui/ptr_eq.rs b/tests/ui/ptr_eq.rs index f28707cc3e92..3fb89257cf1b 100644 --- a/tests/ui/ptr_eq.rs +++ b/tests/ui/ptr_eq.rs @@ -23,23 +23,25 @@ fn main() { //~^ ptr_eq let _ = a as *const _ == b as *const _; //~^ ptr_eq + + // Do not lint: the rhs conversion is needed let _ = a.as_ptr() == b as *const _; - //~^ ptr_eq + + // Do not lint: we have two raw pointers already let _ = a.as_ptr() == b.as_ptr(); - //~^ ptr_eq // Do not lint - let _ = mac!(a, b); let _ = another_mac!(a, b); let a = &mut [1, 2, 3]; let b = &mut [1, 2, 3]; + // Do not lint: the rhs conversion is needed let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _; - //~^ ptr_eq + + // Do not lint: we have two raw pointers already let _ = a.as_mut_ptr() == b.as_mut_ptr(); - //~^ ptr_eq let _ = a == b; let _ = core::ptr::eq(a, b); @@ -51,9 +53,9 @@ fn main() { let _ = x as *const u32 != y as *mut u32 as *const u32; //~^ ptr_eq - #[allow(clippy::eq_op)] + #[expect(clippy::eq_op)] + // Do not lint: casts are needed to not change type let _issue14337 = main as *const () == main as *const (); - //~^ ptr_eq // Do not peel the content of macros let _ = mac!(cast a) as *const _ == mac!(cast b) as *const _; diff --git a/tests/ui/ptr_eq.stderr b/tests/ui/ptr_eq.stderr index 906831b9e031..f613e164b879 100644 --- a/tests/ui/ptr_eq.stderr +++ b/tests/ui/ptr_eq.stderr @@ -14,52 +14,22 @@ LL | let _ = a as *const _ == b as *const _; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a, b)` error: use `std::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq.rs:26:13 - | -LL | let _ = a.as_ptr() == b as *const _; - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a.as_ptr(), b as *const _)` - -error: use `std::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq.rs:28:13 - | -LL | let _ = a.as_ptr() == b.as_ptr(); - | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a.as_ptr(), b.as_ptr())` - -error: use `std::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq.rs:39:13 - | -LL | let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _; - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a.as_mut_ptr(), b as *mut [i32] as *mut _)` - -error: use `std::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq.rs:41:13 - | -LL | let _ = a.as_mut_ptr() == b.as_mut_ptr(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a.as_mut_ptr(), b.as_mut_ptr())` - -error: use `std::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq.rs:48:13 + --> tests/ui/ptr_eq.rs:50:13 | LL | let _ = x as *const u32 == y as *mut u32 as *const u32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(x, y)` error: use `std::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq.rs:51:13 + --> tests/ui/ptr_eq.rs:53:13 | LL | let _ = x as *const u32 != y as *mut u32 as *const u32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `!std::ptr::eq(x, y)` error: use `std::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq.rs:55:23 - | -LL | let _issue14337 = main as *const () == main as *const (); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(main as *const (), main as *const ())` - -error: use `std::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq.rs:59:13 + --> tests/ui/ptr_eq.rs:61:13 | LL | let _ = mac!(cast a) as *const _ == mac!(cast b) as *const _; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(mac!(cast a), mac!(cast b))` -error: aborting due to 10 previous errors +error: aborting due to 5 previous errors diff --git a/tests/ui/ptr_eq_no_std.fixed b/tests/ui/ptr_eq_no_std.fixed index d8ee4ea88f84..48cbad62e1a3 100644 --- a/tests/ui/ptr_eq_no_std.fixed +++ b/tests/ui/ptr_eq_no_std.fixed @@ -32,23 +32,25 @@ fn main() { //~^ ptr_eq let _ = core::ptr::eq(a, b); //~^ ptr_eq - let _ = core::ptr::eq(a.as_ptr(), b as *const _); - //~^ ptr_eq - let _ = core::ptr::eq(a.as_ptr(), b.as_ptr()); - //~^ ptr_eq - // Do not lint + // Do not lint: the rhs conversion is needed + let _ = a.as_ptr() == b as *const _; + + // Do not lint: we have two raw pointers already + let _ = a.as_ptr() == b.as_ptr(); + // Do not lint let _ = mac!(a, b); let _ = another_mac!(a, b); let a = &mut [1, 2, 3]; let b = &mut [1, 2, 3]; - let _ = core::ptr::eq(a.as_mut_ptr(), b as *mut [i32] as *mut _); - //~^ ptr_eq - let _ = core::ptr::eq(a.as_mut_ptr(), b.as_mut_ptr()); - //~^ ptr_eq + // Do not lint: the rhs conversion is needed + let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _; + + // Do not lint: we have two raw pointers already + let _ = a.as_mut_ptr() == b.as_mut_ptr(); let _ = a == b; let _ = core::ptr::eq(a, b); diff --git a/tests/ui/ptr_eq_no_std.rs b/tests/ui/ptr_eq_no_std.rs index a236314c29b7..3827178640ee 100644 --- a/tests/ui/ptr_eq_no_std.rs +++ b/tests/ui/ptr_eq_no_std.rs @@ -32,23 +32,25 @@ fn main() { //~^ ptr_eq let _ = a as *const _ == b as *const _; //~^ ptr_eq + + // Do not lint: the rhs conversion is needed let _ = a.as_ptr() == b as *const _; - //~^ ptr_eq + + // Do not lint: we have two raw pointers already let _ = a.as_ptr() == b.as_ptr(); - //~^ ptr_eq // Do not lint - let _ = mac!(a, b); let _ = another_mac!(a, b); let a = &mut [1, 2, 3]; let b = &mut [1, 2, 3]; + // Do not lint: the rhs conversion is needed let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _; - //~^ ptr_eq + + // Do not lint: we have two raw pointers already let _ = a.as_mut_ptr() == b.as_mut_ptr(); - //~^ ptr_eq let _ = a == b; let _ = core::ptr::eq(a, b); diff --git a/tests/ui/ptr_eq_no_std.stderr b/tests/ui/ptr_eq_no_std.stderr index 5b8135dc8e8b..8c7b1ff76661 100644 --- a/tests/ui/ptr_eq_no_std.stderr +++ b/tests/ui/ptr_eq_no_std.stderr @@ -13,29 +13,5 @@ error: use `core::ptr::eq` when comparing raw pointers LL | let _ = a as *const _ == b as *const _; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a, b)` -error: use `core::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq_no_std.rs:35:13 - | -LL | let _ = a.as_ptr() == b as *const _; - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a.as_ptr(), b as *const _)` - -error: use `core::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq_no_std.rs:37:13 - | -LL | let _ = a.as_ptr() == b.as_ptr(); - | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a.as_ptr(), b.as_ptr())` - -error: use `core::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq_no_std.rs:48:13 - | -LL | let _ = a.as_mut_ptr() == b as *mut [i32] as *mut _; - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a.as_mut_ptr(), b as *mut [i32] as *mut _)` - -error: use `core::ptr::eq` when comparing raw pointers - --> tests/ui/ptr_eq_no_std.rs:50:13 - | -LL | let _ = a.as_mut_ptr() == b.as_mut_ptr(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(a.as_mut_ptr(), b.as_mut_ptr())` - -error: aborting due to 6 previous errors +error: aborting due to 2 previous errors