From 8b642a1883c489c74befca5b75514767a1f80314 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 17 Aug 2024 14:49:35 +0200
Subject: make writes_through_immutable_pointer a hard error

---
 compiler/rustc_const_eval/src/const_eval/error.rs   | 8 +++++++-
 compiler/rustc_const_eval/src/const_eval/machine.rs | 9 +++------
 2 files changed, 10 insertions(+), 7 deletions(-)

(limited to 'compiler/rustc_const_eval/src/const_eval')

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<ConstInt>),
     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<Self>, 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(())
-- 
cgit 1.4.1-3-g733a5