From 8b642a1883c489c74befca5b75514767a1f80314 Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Sat, 17 Aug 2024 14:49:35 +0200 Subject: [PATCH] make writes_through_immutable_pointer a hard error --- .../rustc_const_eval/src/const_eval/error.rs | 8 ++- .../src/const_eval/machine.rs | 9 ++-- compiler/rustc_const_eval/src/errors.rs | 7 --- compiler/rustc_lint/src/lib.rs | 3 +- compiler/rustc_lint_defs/src/builtin.rs | 35 ------------ .../const-eval/ub-write-through-immutable.rs | 9 ++-- .../ub-write-through-immutable.stderr | 54 +++---------------- 7 files changed, 23 insertions(+), 102 deletions(-) diff --git a/compiler/rustc_const_eval/src/const_eval/error.rs b/compiler/rustc_const_eval/src/const_eval/error.rs index 00bbd9337f7..25b32785b7d 100644 --- a/compiler/rustc_const_eval/src/const_eval/error.rs +++ b/compiler/rustc_const_eval/src/const_eval/error.rs @@ -22,6 +22,7 @@ pub enum ConstEvalErrKind { RecursiveStatic, AssertFailure(AssertKind), Panic { msg: Symbol, line: u32, col: u32, file: Symbol }, + WriteThroughImmutablePointer, } impl MachineStopType for ConstEvalErrKind { @@ -35,12 +36,16 @@ impl MachineStopType for ConstEvalErrKind { Panic { .. } => const_eval_panic, RecursiveStatic => const_eval_recursive_static, AssertFailure(x) => x.diagnostic_message(), + WriteThroughImmutablePointer => const_eval_write_through_immutable_pointer, } } fn add_args(self: Box, adder: &mut dyn FnMut(DiagArgName, DiagArgValue)) { use ConstEvalErrKind::*; match *self { - RecursiveStatic | ConstAccessesMutGlobal | ModifiedGlobal => {} + RecursiveStatic + | ConstAccessesMutGlobal + | ModifiedGlobal + | WriteThroughImmutablePointer => {} AssertFailure(kind) => kind.add_args(adder), Panic { msg, line, col, file } => { adder("msg".into(), msg.into_diag_arg()); @@ -159,6 +164,7 @@ where /// Emit a lint from a const-eval situation, with a backtrace. // Even if this is unused, please don't remove it -- chances are we will need to emit a lint during const-eval again in the future! +#[allow(unused)] pub(super) fn lint<'tcx, L>( tcx: TyCtxtAt<'tcx>, machine: &CompileTimeMachine<'tcx>, diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs index a075bdc1911..f010e5cfbb7 100644 --- a/compiler/rustc_const_eval/src/const_eval/machine.rs +++ b/compiler/rustc_const_eval/src/const_eval/machine.rs @@ -12,7 +12,6 @@ use rustc_middle::query::TyCtxtAt; use rustc_middle::ty::layout::{FnAbiOf, TyAndLayout}; use rustc_middle::ty::{self, TyCtxt}; use rustc_middle::{bug, mir}; -use rustc_session::lint::builtin::WRITES_THROUGH_IMMUTABLE_POINTER; use rustc_span::symbol::{sym, Symbol}; use rustc_span::Span; use rustc_target::abi::{Align, Size}; @@ -729,8 +728,8 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> { } fn before_memory_write( - tcx: TyCtxtAt<'tcx>, - machine: &mut Self, + _tcx: TyCtxtAt<'tcx>, + _machine: &mut Self, _alloc_extra: &mut Self::AllocExtra, (_alloc_id, immutable): (AllocId, bool), range: AllocRange, @@ -741,9 +740,7 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> { } // Reject writes through immutable pointers. if immutable { - super::lint(tcx, machine, WRITES_THROUGH_IMMUTABLE_POINTER, |frames| { - crate::errors::WriteThroughImmutablePointer { frames } - }); + return Err(ConstEvalErrKind::WriteThroughImmutablePointer.into()); } // Everything else is fine. Ok(()) diff --git a/compiler/rustc_const_eval/src/errors.rs b/compiler/rustc_const_eval/src/errors.rs index 7afb92c08ec..ec344543c5c 100644 --- a/compiler/rustc_const_eval/src/errors.rs +++ b/compiler/rustc_const_eval/src/errors.rs @@ -407,13 +407,6 @@ pub struct ConstEvalError { pub frame_notes: Vec, } -#[derive(LintDiagnostic)] -#[diag(const_eval_write_through_immutable_pointer)] -pub struct WriteThroughImmutablePointer { - #[subdiagnostic] - pub frames: Vec, -} - #[derive(Diagnostic)] #[diag(const_eval_nullary_intrinsic_fail)] pub struct NullaryIntrinsicError { diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs index 4f3933d461b..547f7eb8e2a 100644 --- a/compiler/rustc_lint/src/lib.rs +++ b/compiler/rustc_lint/src/lib.rs @@ -569,7 +569,8 @@ fn register_builtins(store: &mut LintStore) { "byte_slice_in_packed_struct_with_derive", "converted into hard error, see issue #107457 \ for more information", - ) + ); + store.register_removed("writes_through_immutable_pointer", "converted into hard error"); } fn register_internals(store: &mut LintStore) { diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs index c731b03a875..3c0181a5e6e 100644 --- a/compiler/rustc_lint_defs/src/builtin.rs +++ b/compiler/rustc_lint_defs/src/builtin.rs @@ -142,7 +142,6 @@ declare_lint_pass! { USELESS_DEPRECATED, WARNINGS, WASM_C_ABI, - WRITES_THROUGH_IMMUTABLE_POINTER, // tidy-alphabetical-end ] } @@ -4696,40 +4695,6 @@ declare_lint! { }; } -declare_lint! { - /// The `writes_through_immutable_pointer` lint detects writes through pointers derived from - /// shared references. - /// - /// ### Example - /// - /// ```rust,compile_fail - /// #![feature(const_mut_refs)] - /// const WRITE_AFTER_CAST: () = unsafe { - /// let mut x = 0; - /// let ptr = &x as *const i32 as *mut i32; - /// *ptr = 0; - /// }; - /// ``` - /// - /// {{produces}} - /// - /// ### Explanation - /// - /// Shared references are immutable (when there is no `UnsafeCell` involved), - /// and writing through them or through pointers derived from them is Undefined Behavior. - /// The compiler recently learned to detect such Undefined Behavior during compile-time - /// evaluation, and in the future this will raise a hard error. - /// - /// [future-incompatible]: ../index.md#future-incompatible-lints - pub WRITES_THROUGH_IMMUTABLE_POINTER, - Warn, - "shared references are immutable, and pointers derived from them must not be written to", - @future_incompatible = FutureIncompatibleInfo { - reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps, - reference: "issue #X ", - }; -} - declare_lint! { /// The `private_macro_use` lint detects private macros that are imported /// with `#[macro_use]`. diff --git a/tests/ui/consts/const-eval/ub-write-through-immutable.rs b/tests/ui/consts/const-eval/ub-write-through-immutable.rs index 945367f1823..9860b8fde4a 100644 --- a/tests/ui/consts/const-eval/ub-write-through-immutable.rs +++ b/tests/ui/consts/const-eval/ub-write-through-immutable.rs @@ -1,6 +1,5 @@ //! Ensure we catch UB due to writing through a shared reference. #![feature(const_mut_refs, const_refs_to_cell)] -#![deny(writes_through_immutable_pointer)] #![allow(invalid_reference_casting)] use std::mem; @@ -9,15 +8,15 @@ use std::cell::UnsafeCell; const WRITE_AFTER_CAST: () = unsafe { let mut x = 0; let ptr = &x as *const i32 as *mut i32; - *ptr = 0; //~ERROR: writes_through_immutable_pointer - //~^ previously accepted + *ptr = 0; //~ERROR: evaluation of constant value failed + //~| immutable }; const WRITE_AFTER_TRANSMUTE: () = unsafe { let mut x = 0; let ptr: *mut i32 = mem::transmute(&x); - *ptr = 0; //~ERROR: writes_through_immutable_pointer - //~^ previously accepted + *ptr = 0; //~ERROR: evaluation of constant value failed + //~| immutable }; // it's okay when there is interior mutability; diff --git a/tests/ui/consts/const-eval/ub-write-through-immutable.stderr b/tests/ui/consts/const-eval/ub-write-through-immutable.stderr index 27eb2d2c0d1..dbcd35e0b88 100644 --- a/tests/ui/consts/const-eval/ub-write-through-immutable.stderr +++ b/tests/ui/consts/const-eval/ub-write-through-immutable.stderr @@ -1,55 +1,15 @@ -error: writing through a pointer that was derived from a shared (immutable) reference - --> $DIR/ub-write-through-immutable.rs:12:5 +error[E0080]: evaluation of constant value failed + --> $DIR/ub-write-through-immutable.rs:11:5 | LL | *ptr = 0; - | ^^^^^^^^ - | - = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! - = note: for more information, see issue #X -note: the lint level is defined here - --> $DIR/ub-write-through-immutable.rs:3:9 - | -LL | #![deny(writes_through_immutable_pointer)] - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | ^^^^^^^^ writing through a pointer that was derived from a shared (immutable) reference -error: writing through a pointer that was derived from a shared (immutable) reference - --> $DIR/ub-write-through-immutable.rs:19:5 +error[E0080]: evaluation of constant value failed + --> $DIR/ub-write-through-immutable.rs:18:5 | LL | *ptr = 0; - | ^^^^^^^^ - | - = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! - = note: for more information, see issue #X + | ^^^^^^^^ writing through a pointer that was derived from a shared (immutable) reference error: aborting due to 2 previous errors -Future incompatibility report: Future breakage diagnostic: -error: writing through a pointer that was derived from a shared (immutable) reference - --> $DIR/ub-write-through-immutable.rs:12:5 - | -LL | *ptr = 0; - | ^^^^^^^^ - | - = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! - = note: for more information, see issue #X -note: the lint level is defined here - --> $DIR/ub-write-through-immutable.rs:3:9 - | -LL | #![deny(writes_through_immutable_pointer)] - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -Future breakage diagnostic: -error: writing through a pointer that was derived from a shared (immutable) reference - --> $DIR/ub-write-through-immutable.rs:19:5 - | -LL | *ptr = 0; - | ^^^^^^^^ - | - = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! - = note: for more information, see issue #X -note: the lint level is defined here - --> $DIR/ub-write-through-immutable.rs:3:9 - | -LL | #![deny(writes_through_immutable_pointer)] - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - +For more information about this error, try `rustc --explain E0080`.