diff options
| -rw-r--r-- | compiler/rustc_lint/src/reference_casting.rs | 112 | ||||
| -rw-r--r-- | tests/ui/lint/reference_casting.rs | 6 | ||||
| -rw-r--r-- | tests/ui/lint/reference_casting.stderr | 74 |
3 files changed, 87 insertions, 105 deletions
diff --git a/compiler/rustc_lint/src/reference_casting.rs b/compiler/rustc_lint/src/reference_casting.rs index 717d44cea33..39def599be8 100644 --- a/compiler/rustc_lint/src/reference_casting.rs +++ b/compiler/rustc_lint/src/reference_casting.rs @@ -104,99 +104,51 @@ fn is_operation_we_care_about<'tcx>( deref_assign_or_addr_of(e).or_else(|| ptr_write(cx, e)) } -fn is_cast_from_const_to_mut<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) -> bool { - let e = e.peel_blocks(); +fn is_cast_from_const_to_mut<'tcx>(cx: &LateContext<'tcx>, orig_expr: &'tcx Expr<'tcx>) -> bool { + let mut need_check_freeze = false; + let mut e = orig_expr; - fn from_casts<'tcx>( - cx: &LateContext<'tcx>, - e: &'tcx Expr<'tcx>, - need_check_freeze: &mut bool, - ) -> Option<&'tcx Expr<'tcx>> { - // <expr> as *mut ... - let mut e = if let ExprKind::Cast(e, t) = e.kind - && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Mut, .. }) = cx.typeck_results().node_type(t.hir_id).kind() { - e - // <expr>.cast_mut() + let end_ty = cx.typeck_results().node_type(orig_expr.hir_id); + + // Bail out early if the end type is **not** a mutable pointer. + if !matches!(end_ty.kind(), ty::RawPtr(TypeAndMut { ty: _, mutbl: Mutability::Mut })) { + return false; + } + + loop { + e = e.peel_blocks(); + // <expr> as ... + e = if let ExprKind::Cast(expr, _) = e.kind { + expr + // <expr>.cast(), <expr>.cast_mut() or <expr>.cast_const() } else if let ExprKind::MethodCall(_, expr, [], _) = e.kind && let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id) - && cx.tcx.is_diagnostic_item(sym::ptr_cast_mut, def_id) { + && matches!( + cx.tcx.get_diagnostic_name(def_id), + Some(sym::ptr_cast | sym::const_ptr_cast | sym::ptr_cast_mut | sym::ptr_cast_const) + ) + { expr - // UnsafeCell::raw_get(<expr>) + // ptr::from_ref(<expr>), UnsafeCell::raw_get(<expr>) or mem::transmute<_, _>(<expr>) } else if let ExprKind::Call(path, [arg]) = e.kind && let ExprKind::Path(ref qpath) = path.kind && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() - && cx.tcx.is_diagnostic_item(sym::unsafe_cell_raw_get, def_id) + && matches!( + cx.tcx.get_diagnostic_name(def_id), + Some(sym::ptr_from_ref | sym::unsafe_cell_raw_get | sym::transmute) + ) { - *need_check_freeze = true; + if cx.tcx.is_diagnostic_item(sym::unsafe_cell_raw_get, def_id) { + need_check_freeze = true; + } arg } else { - return None; + break; }; - - let mut had_at_least_one_cast = false; - loop { - e = e.peel_blocks(); - // <expr> as *mut/const ... or <expr> as <uint> - e = if let ExprKind::Cast(expr, t) = e.kind - && matches!(cx.typeck_results().node_type(t.hir_id).kind(), ty::RawPtr(_) | ty::Uint(_)) { - had_at_least_one_cast = true; - expr - // <expr>.cast(), <expr>.cast_mut() or <expr>.cast_const() - } else if let ExprKind::MethodCall(_, expr, [], _) = e.kind - && let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id) - && matches!( - cx.tcx.get_diagnostic_name(def_id), - Some(sym::ptr_cast | sym::const_ptr_cast | sym::ptr_cast_mut | sym::ptr_cast_const) - ) - { - had_at_least_one_cast = true; - expr - // ptr::from_ref(<expr>) or UnsafeCell::raw_get(<expr>) - } else if let ExprKind::Call(path, [arg]) = e.kind - && let ExprKind::Path(ref qpath) = path.kind - && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() - && matches!( - cx.tcx.get_diagnostic_name(def_id), - Some(sym::ptr_from_ref | sym::unsafe_cell_raw_get) - ) - { - if cx.tcx.is_diagnostic_item(sym::unsafe_cell_raw_get, def_id) { - *need_check_freeze = true; - } - return Some(arg); - } else if had_at_least_one_cast { - return Some(e); - } else { - return None; - }; - } } - fn from_transmute<'tcx>( - cx: &LateContext<'tcx>, - e: &'tcx Expr<'tcx>, - ) -> Option<&'tcx Expr<'tcx>> { - // mem::transmute::<_, *mut _>(<expr>) - if let ExprKind::Call(path, [arg]) = e.kind - && let ExprKind::Path(ref qpath) = path.kind - && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() - && cx.tcx.is_diagnostic_item(sym::transmute, def_id) - && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Mut, .. }) = cx.typeck_results().node_type(e.hir_id).kind() { - Some(arg) - } else { - None - } - } - - let mut need_check_freeze = false; - let Some(e) = from_casts(cx, e, &mut need_check_freeze).or_else(|| from_transmute(cx, e)) - else { - return false; - }; - - let e = e.peel_blocks(); - let node_type = cx.typeck_results().node_type(e.hir_id); - if let ty::Ref(_, inner_ty, Mutability::Not) = node_type.kind() { + let start_ty = cx.typeck_results().node_type(e.hir_id); + if let ty::Ref(_, inner_ty, Mutability::Not) = start_ty.kind() { // If an UnsafeCell method is involved we need to additionaly check the // inner type for the presence of the Freeze trait (ie does NOT contain // an UnsafeCell), since in that case we would incorrectly lint on valid casts. diff --git a/tests/ui/lint/reference_casting.rs b/tests/ui/lint/reference_casting.rs index 18c66b2a13e..3d73c261e55 100644 --- a/tests/ui/lint/reference_casting.rs +++ b/tests/ui/lint/reference_casting.rs @@ -36,6 +36,8 @@ unsafe fn ref_to_mut() { //~^ ERROR casting `&T` to `&mut T` is undefined behavior let _num = &mut *std::mem::transmute::<_, *mut i32>(num); //~^ ERROR casting `&T` to `&mut T` is undefined behavior + let _num = &mut *(std::mem::transmute::<_, *mut i32>(num) as *mut i32); + //~^ ERROR casting `&T` to `&mut T` is undefined behavior let _num = &mut *std::cell::UnsafeCell::raw_get( //~^ ERROR casting `&T` to `&mut T` is undefined behavior num as *const i32 as *const std::cell::UnsafeCell<i32> @@ -52,6 +54,8 @@ unsafe fn ref_to_mut() { //~^ ERROR casting `&T` to `&mut T` is undefined behavior let _num = &mut *(num as *const _ as usize as *mut i32); //~^ ERROR casting `&T` to `&mut T` is undefined behavior + let _num = &mut *(std::mem::transmute::<_, *mut _>(num as *const i32) as *mut i32); + //~^ ERROR casting `&T` to `&mut T` is undefined behavior static NUM: &'static i32 = &2; let num = NUM as *const i32 as *mut i32; @@ -95,6 +99,8 @@ unsafe fn assign_to_ref() { //~^ ERROR assigning to `&T` is undefined behavior *std::mem::transmute::<_, *mut i32>(num) += 1; //~^ ERROR assigning to `&T` is undefined behavior + *(std::mem::transmute::<_, *mut i32>(num) as *mut i32) += 1; + //~^ ERROR assigning to `&T` is undefined behavior std::ptr::write( //~^ ERROR assigning to `&T` is undefined behavior std::mem::transmute::<*const i32, *mut i32>(num), diff --git a/tests/ui/lint/reference_casting.stderr b/tests/ui/lint/reference_casting.stderr index d4e56048a8a..8f89cf9805b 100644 --- a/tests/ui/lint/reference_casting.stderr +++ b/tests/ui/lint/reference_casting.stderr @@ -82,6 +82,14 @@ LL | let _num = &mut *std::mem::transmute::<_, *mut i32>(num); error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` --> $DIR/reference_casting.rs:39:16 | +LL | let _num = &mut *(std::mem::transmute::<_, *mut i32>(num) as *mut i32); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> + +error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` + --> $DIR/reference_casting.rs:41:16 + | LL | let _num = &mut *std::cell::UnsafeCell::raw_get( | ________________^ LL | | @@ -92,7 +100,7 @@ LL | | ); = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` - --> $DIR/reference_casting.rs:45:16 + --> $DIR/reference_casting.rs:47:16 | LL | let deferred = num as *const i32 as *mut i32; | ----------------------------- casting happend here @@ -102,7 +110,7 @@ LL | let _num = &mut *deferred; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` - --> $DIR/reference_casting.rs:48:16 + --> $DIR/reference_casting.rs:50:16 | LL | let deferred = (std::ptr::from_ref(num) as *const i32 as *const i32).cast_mut() as *mut i32; | ---------------------------------------------------------------------------- casting happend here @@ -112,7 +120,7 @@ LL | let _num = &mut *deferred; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` - --> $DIR/reference_casting.rs:51:16 + --> $DIR/reference_casting.rs:53:16 | LL | let deferred = (std::ptr::from_ref(num) as *const i32 as *const i32).cast_mut() as *mut i32; | ---------------------------------------------------------------------------- casting happend here @@ -123,7 +131,7 @@ LL | let _num = &mut *deferred_rebind; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` - --> $DIR/reference_casting.rs:53:16 + --> $DIR/reference_casting.rs:55:16 | LL | let _num = &mut *(num as *const _ as usize as *mut i32); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -131,7 +139,15 @@ LL | let _num = &mut *(num as *const _ as usize as *mut i32); = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` - --> $DIR/reference_casting.rs:60:16 + --> $DIR/reference_casting.rs:57:16 + | +LL | let _num = &mut *(std::mem::transmute::<_, *mut _>(num as *const i32) as *mut i32); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> + +error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` + --> $DIR/reference_casting.rs:64:16 | LL | let num = NUM as *const i32 as *mut i32; | ----------------------------- casting happend here @@ -142,7 +158,7 @@ LL | let _num = &mut *num; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` - --> $DIR/reference_casting.rs:64:9 + --> $DIR/reference_casting.rs:68:9 | LL | &mut *((this as *const _) as *mut _) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -150,7 +166,7 @@ LL | &mut *((this as *const _) as *mut _) = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` - --> $DIR/reference_casting.rs:69:18 + --> $DIR/reference_casting.rs:73:18 | LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -158,7 +174,7 @@ LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *con = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` - --> $DIR/reference_casting.rs:74:18 + --> $DIR/reference_casting.rs:78:18 | LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -166,7 +182,7 @@ LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *con = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:84:5 + --> $DIR/reference_casting.rs:88:5 | LL | *(a as *const _ as *mut _) = String::from("Replaced"); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -174,7 +190,7 @@ LL | *(a as *const _ as *mut _) = String::from("Replaced"); = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:86:5 + --> $DIR/reference_casting.rs:90:5 | LL | *(a as *const _ as *mut String) += " world"; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -182,7 +198,7 @@ LL | *(a as *const _ as *mut String) += " world"; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:88:5 + --> $DIR/reference_casting.rs:92:5 | LL | *std::ptr::from_ref(num).cast_mut() += 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -190,7 +206,7 @@ LL | *std::ptr::from_ref(num).cast_mut() += 1; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:90:5 + --> $DIR/reference_casting.rs:94:5 | LL | *std::ptr::from_ref({ num }).cast_mut() += 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -198,7 +214,7 @@ LL | *std::ptr::from_ref({ num }).cast_mut() += 1; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:92:5 + --> $DIR/reference_casting.rs:96:5 | LL | *{ std::ptr::from_ref(num) }.cast_mut() += 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -206,7 +222,7 @@ LL | *{ std::ptr::from_ref(num) }.cast_mut() += 1; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:94:5 + --> $DIR/reference_casting.rs:98:5 | LL | *(std::ptr::from_ref({ num }) as *mut i32) += 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -214,7 +230,7 @@ LL | *(std::ptr::from_ref({ num }) as *mut i32) += 1; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:96:5 + --> $DIR/reference_casting.rs:100:5 | LL | *std::mem::transmute::<_, *mut i32>(num) += 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -222,7 +238,15 @@ LL | *std::mem::transmute::<_, *mut i32>(num) += 1; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:98:5 + --> $DIR/reference_casting.rs:102:5 + | +LL | *(std::mem::transmute::<_, *mut i32>(num) as *mut i32) += 1; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> + +error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` + --> $DIR/reference_casting.rs:104:5 | LL | / std::ptr::write( LL | | @@ -234,7 +258,7 @@ LL | | ); = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:105:5 + --> $DIR/reference_casting.rs:111:5 | LL | let value = num as *const i32 as *mut i32; | ----------------------------- casting happend here @@ -244,7 +268,7 @@ LL | *value = 1; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:108:5 + --> $DIR/reference_casting.rs:114:5 | LL | let value = num as *const i32 as *mut i32; | ----------------------------- casting happend here @@ -255,7 +279,7 @@ LL | *value_rebind = 1; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:110:5 + --> $DIR/reference_casting.rs:116:5 | LL | *(num as *const i32).cast::<i32>().cast_mut() = 2; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -263,7 +287,7 @@ LL | *(num as *const i32).cast::<i32>().cast_mut() = 2; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:112:5 + --> $DIR/reference_casting.rs:118:5 | LL | *(num as *const _ as usize as *mut i32) = 2; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -271,7 +295,7 @@ LL | *(num as *const _ as usize as *mut i32) = 2; = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:114:5 + --> $DIR/reference_casting.rs:120:5 | LL | let value = num as *const i32 as *mut i32; | ----------------------------- casting happend here @@ -282,7 +306,7 @@ LL | std::ptr::write(value, 2); = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:116:5 + --> $DIR/reference_casting.rs:122:5 | LL | let value = num as *const i32 as *mut i32; | ----------------------------- casting happend here @@ -293,7 +317,7 @@ LL | std::ptr::write_unaligned(value, 2); = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:118:5 + --> $DIR/reference_casting.rs:124:5 | LL | let value = num as *const i32 as *mut i32; | ----------------------------- casting happend here @@ -304,12 +328,12 @@ LL | std::ptr::write_volatile(value, 2); = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` - --> $DIR/reference_casting.rs:122:9 + --> $DIR/reference_casting.rs:128:9 | LL | *(this as *const _ as *mut _) = a; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> -error: aborting due to 35 previous errors +error: aborting due to 38 previous errors |