panic when an interpreter error gets unintentionally discarded

12 files changed, 262 insertions, 147 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index 32f90254a94..05264d32c6b 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -13,9 +13,9 @@ use rustc_target::abi::{Abi, Align, HasDataLayout, Size};
 use tracing::{instrument, trace};
 
 use super::{
-    AllocRef, AllocRefMut, CheckAlignMsg, CtfeProvenance, ImmTy, Immediate, InterpCx, InterpResult,
-    Machine, MemoryKind, Misalignment, OffsetMode, OpTy, Operand, Pointer, Projectable, Provenance,
-    Scalar, alloc_range, mir_assign_valid_types,
+    AllocRef, AllocRefMut, CheckAlignMsg, CtfeProvenance, DiscardInterpError, ImmTy, Immediate,
+    InterpCx, InterpResult, Machine, MemoryKind, Misalignment, OffsetMode, OpTy, Operand, Pointer,
+    Projectable, Provenance, Scalar, alloc_range, mir_assign_valid_types,
 };
 
 #[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
@@ -490,9 +490,16 @@ where
         // If an access is both OOB and misaligned, we want to see the bounds error.
         // However we have to call `check_misalign` first to make the borrow checker happy.
         let misalign_err = self.check_misalign(mplace.mplace.misaligned, CheckAlignMsg::BasedOn);
-        let a = self.get_ptr_alloc_mut(mplace.ptr(), size)?;
-        misalign_err?;
-        Ok(a)
+        match self.get_ptr_alloc_mut(mplace.ptr(), size) {
+            Ok(a) => {
+                misalign_err?;
+                Ok(a)
+            }
+            Err(e) => {
+                misalign_err.discard_interp_err();
+                Err(e)
+            }
+        }
     }
 
     /// Turn a local in the current frame into a place.
diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index 203cceccd9d..3c9fdd73100 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -17,8 +17,8 @@ use rustc_hir as hir;
 use rustc_middle::bug;
 use rustc_middle::mir::interpret::ValidationErrorKind::{self, *};
 use rustc_middle::mir::interpret::{
-    ExpectedKind, InterpError, InvalidMetaKind, Misalignment, PointerKind, Provenance,
-    UnsupportedOpInfo, ValidationErrorInfo, alloc_range,
+    ExpectedKind, InterpError, InterpErrorInfo, InvalidMetaKind, Misalignment, PointerKind,
+    Provenance, UnsupportedOpInfo, ValidationErrorInfo, alloc_range,
 };
 use rustc_middle::ty::layout::{LayoutCx, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{self, Ty};
@@ -95,16 +95,19 @@ macro_rules! try_validation {
             Ok(x) => x,
             // We catch the error and turn it into a validation failure. We are okay with
             // allocation here as this can only slow down builds that fail anyway.
-            Err(e) => match e.kind() {
-                $(
-                    $($p)|+ =>
-                       throw_validation_failure!(
-                            $where,
-                            $kind
-                        )
-                ),+,
-                #[allow(unreachable_patterns)]
-                _ => Err::<!, _>(e)?,
+            Err(e) => {
+                let (kind, backtrace) = e.into_parts();
+                match kind {
+                    $(
+                        $($p)|+ => {
+                            throw_validation_failure!(
+                                $where,
+                                $kind
+                            )
+                        }
+                    ),+,
+                    _ => Err::<!, _>(InterpErrorInfo::from_parts(kind, backtrace))?,
+                }
             }
         }
     }};
@@ -510,7 +513,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
             Ub(DanglingIntPointer { addr: i, .. }) => DanglingPtrNoProvenance {
                 ptr_kind,
                 // FIXME this says "null pointer" when null but we need translate
-                pointer: format!("{}", Pointer::<Option<AllocId>>::from_addr_invalid(*i))
+                pointer: format!("{}", Pointer::<Option<AllocId>>::from_addr_invalid(i))
             },
             Ub(PointerOutOfBounds { .. }) => DanglingPtrOutOfBounds {
                 ptr_kind
@@ -1231,7 +1234,8 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValueVisitor<'tcx, M> for ValidityVisitor<'rt,
                     Err(err) => {
                         // For some errors we might be able to provide extra information.
                         // (This custom logic does not fit the `try_validation!` macro.)
-                        match err.kind() {
+                        let (kind, backtrace) = err.into_parts();
+                        match kind {
                             Ub(InvalidUninitBytes(Some((_alloc_id, access)))) | Unsup(ReadPointerAsInt(Some((_alloc_id, access)))) => {
                                 // Some byte was uninitialized, determine which
                                 // element that byte belongs to so we can
@@ -1242,7 +1246,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValueVisitor<'tcx, M> for ValidityVisitor<'rt,
                                 .unwrap();
                                 self.path.push(PathElem::ArrayElem(i));
 
-                                if matches!(err.kind(), Ub(InvalidUninitBytes(_))) {
+                                if matches!(kind, Ub(InvalidUninitBytes(_))) {
                                     throw_validation_failure!(self.path, Uninit { expected })
                                 } else {
                                     throw_validation_failure!(self.path, PointerAsInt { expected })
@@ -1250,7 +1254,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValueVisitor<'tcx, M> for ValidityVisitor<'rt,
                             }
 
                             // Propagate upwards (that will also check for unexpected errors).
-                            _ => return Err(err),
+                            _ => return Err(InterpErrorInfo::from_parts(kind, backtrace)),
                         }
                     }
                 }
@@ -1282,7 +1286,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValueVisitor<'tcx, M> for ValidityVisitor<'rt,
                     // It's not great to catch errors here, since we can't give a very good path,
                     // but it's better than ICEing.
                     Ub(InvalidVTableTrait { vtable_dyn_type, expected_dyn_type }) => {
-                        InvalidMetaWrongTrait { vtable_dyn_type, expected_dyn_type: *expected_dyn_type }
+                        InvalidMetaWrongTrait { vtable_dyn_type, expected_dyn_type }
                     },
                 );
             }
diff --git a/compiler/rustc_const_eval/src/util/check_validity_requirement.rs b/compiler/rustc_const_eval/src/util/check_validity_requirement.rs
index 19393188c9a..421648d9e7b 100644
--- a/compiler/rustc_const_eval/src/util/check_validity_requirement.rs
+++ b/compiler/rustc_const_eval/src/util/check_validity_requirement.rs
@@ -1,4 +1,5 @@
 use rustc_middle::bug;
+use rustc_middle::mir::interpret::DiscardInterpError;
 use rustc_middle::ty::layout::{
     HasTyCtxt, LayoutCx, LayoutError, LayoutOf, TyAndLayout, ValidityRequirement,
 };
@@ -75,7 +76,8 @@ fn check_validity_requirement_strict<'tcx>(
             /*recursive*/ false,
             /*reset_provenance_and_padding*/ false,
         )
-        .is_ok())
+        .discard_interp_err()
+        .is_some())
 }
 
 /// Implements the 'lax' (default) version of the [`check_validity_requirement`] checks; see that
diff --git a/compiler/rustc_middle/src/mir/interpret/error.rs b/compiler/rustc_middle/src/mir/interpret/error.rs
index 46646e759d5..06fdb9e1ecd 100644
--- a/compiler/rustc_middle/src/mir/interpret/error.rs
+++ b/compiler/rustc_middle/src/mir/interpret/error.rs
@@ -1,7 +1,7 @@
 use std::any::Any;
 use std::backtrace::Backtrace;
 use std::borrow::Cow;
-use std::fmt;
+use std::{fmt, mem};
 
 use either::Either;
 use rustc_ast_ir::Mutability;
@@ -104,13 +104,57 @@ rustc_data_structures::static_assert_size!(InterpErrorInfo<'_>, 8);
 /// These should always be constructed by calling `.into()` on
 /// an `InterpError`. In `rustc_mir::interpret`, we have `throw_err_*`
 /// macros for this.
+///
+/// Interpreter errors must *not* be silently discarded (that will lead to a panic). Instead,
+/// explicitly call `discard_interp_err` if this is really the right thing to do. Note that if
+/// this happens during const-eval or in Miri, it could lead to a UB error being lost!
 #[derive(Debug)]
 pub struct InterpErrorInfo<'tcx>(Box<InterpErrorInfoInner<'tcx>>);
 
+/// Calling `.ok()` on an `InterpResult` leads to a panic because of the guard.
+/// To still let people opt-in to discarding interpreter errors, we have this extension trait.
+pub trait DiscardInterpError {
+    type Output;
+
+    fn discard_interp_err(self) -> Option<Self::Output>;
+}
+
+impl<'tcx, T> DiscardInterpError for InterpResult<'tcx, T> {
+    type Output = T;
+
+    fn discard_interp_err(self) -> Option<Self::Output> {
+        match self {
+            Ok(v) => Some(v),
+            Err(e) => {
+                // Disarm the guard.
+                mem::forget(e.0.guard);
+                None
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+struct Guard;
+
+impl Drop for Guard {
+    fn drop(&mut self) {
+        // We silence the guard if we are already panicking, to avoid double-panics.
+        if !std::thread::panicking() {
+            panic!(
+                "an interpreter error got improperly discarded; use `discard_interp_err()` instead of `ok()` if this is intentional"
+            );
+        }
+    }
+}
+
 #[derive(Debug)]
 struct InterpErrorInfoInner<'tcx> {
     kind: InterpError<'tcx>,
     backtrace: InterpErrorBacktrace,
+    /// This makes us panic on drop. This is used to catch
+    /// accidentally discarding an interpreter error.
+    guard: Guard,
 }
 
 #[derive(Debug)]
@@ -151,15 +195,25 @@ impl InterpErrorBacktrace {
 
 impl<'tcx> InterpErrorInfo<'tcx> {
     pub fn into_parts(self) -> (InterpError<'tcx>, InterpErrorBacktrace) {
-        let InterpErrorInfo(box InterpErrorInfoInner { kind, backtrace }) = self;
+        let InterpErrorInfo(box InterpErrorInfoInner { kind, backtrace, guard }) = self;
+        mem::forget(guard); // The error got explicitly discarded right here.
         (kind, backtrace)
     }
 
     pub fn into_kind(self) -> InterpError<'tcx> {
-        let InterpErrorInfo(box InterpErrorInfoInner { kind, .. }) = self;
+        let InterpErrorInfo(box InterpErrorInfoInner { kind, guard, .. }) = self;
+        mem::forget(guard); // The error got explicitly discarded right here.
         kind
     }
 
+    pub fn discard_interp_err(self) {
+        mem::forget(self.0.guard); // The error got explicitly discarded right here.
+    }
+
+    pub fn from_parts(kind: InterpError<'tcx>, backtrace: InterpErrorBacktrace) -> Self {
+        Self(Box::new(InterpErrorInfoInner { kind, backtrace, guard: Guard }))
+    }
+
     #[inline]
     pub fn kind(&self) -> &InterpError<'tcx> {
         &self.0.kind
@@ -191,6 +245,7 @@ impl<'tcx> From<InterpError<'tcx>> for InterpErrorInfo<'tcx> {
         InterpErrorInfo(Box::new(InterpErrorInfoInner {
             kind,
             backtrace: InterpErrorBacktrace::new(),
+            guard: Guard,
         }))
     }
 }
diff --git a/compiler/rustc_middle/src/mir/interpret/mod.rs b/compiler/rustc_middle/src/mir/interpret/mod.rs
index d7809cc4343..8ce6f9d2300 100644
--- a/compiler/rustc_middle/src/mir/interpret/mod.rs
+++ b/compiler/rustc_middle/src/mir/interpret/mod.rs
@@ -34,12 +34,12 @@ pub use self::allocation::{
     InitChunkIter, alloc_range,
 };
 pub use self::error::{
-    BadBytesAccess, CheckAlignMsg, CheckInAllocMsg, ErrorHandled, EvalStaticInitializerRawResult,
-    EvalToAllocationRawResult, EvalToConstValueResult, EvalToValTreeResult, ExpectedKind,
-    InterpError, InterpErrorInfo, InterpResult, InvalidMetaKind, InvalidProgramInfo,
-    MachineStopType, Misalignment, PointerKind, ReportedErrorInfo, ResourceExhaustionInfo,
-    ScalarSizeMismatch, UndefinedBehaviorInfo, UnsupportedOpInfo, ValidationErrorInfo,
-    ValidationErrorKind,
+    BadBytesAccess, CheckAlignMsg, CheckInAllocMsg, DiscardInterpError, ErrorHandled,
+    EvalStaticInitializerRawResult, EvalToAllocationRawResult, EvalToConstValueResult,
+    EvalToValTreeResult, ExpectedKind, InterpError, InterpErrorInfo, InterpResult, InvalidMetaKind,
+    InvalidProgramInfo, MachineStopType, Misalignment, PointerKind, ReportedErrorInfo,
+    ResourceExhaustionInfo, ScalarSizeMismatch, UndefinedBehaviorInfo, UnsupportedOpInfo,
+    ValidationErrorInfo, ValidationErrorKind,
 };
 pub use self::pointer::{CtfeProvenance, Pointer, PointerArithmetic, Provenance};
 pub use self::value::Scalar;
diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index 88dc8e74a8c..905143b2efb 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -3,7 +3,9 @@
 //! Currently, this pass only propagates scalar values.
 
 use rustc_const_eval::const_eval::{DummyMachine, throw_machine_stop_str};
-use rustc_const_eval::interpret::{ImmTy, Immediate, InterpCx, OpTy, PlaceTy, Projectable};
+use rustc_const_eval::interpret::{
+    DiscardInterpError, ImmTy, Immediate, InterpCx, OpTy, PlaceTy, Projectable,
+};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::DefKind;
 use rustc_middle::bug;
@@ -364,8 +366,10 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
                 }
             }
             Operand::Constant(box constant) => {
-                if let Ok(constant) =
-                    self.ecx.eval_mir_constant(&constant.const_, constant.span, None)
+                if let Some(constant) = self
+                    .ecx
+                    .eval_mir_constant(&constant.const_, constant.span, None)
+                    .discard_interp_err()
                 {
                     self.assign_constant(state, place, constant, &[]);
                 }
@@ -387,7 +391,7 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
         for &(mut proj_elem) in projection {
             if let PlaceElem::Index(index) = proj_elem {
                 if let FlatSet::Elem(index) = state.get(index.into(), &self.map)
-                    && let Ok(offset) = index.to_target_usize(&self.tcx)
+                    && let Some(offset) = index.to_target_usize(&self.tcx).discard_interp_err()
                     && let Some(min_length) = offset.checked_add(1)
                 {
                     proj_elem = PlaceElem::ConstantIndex { offset, min_length, from_end: false };
@@ -395,35 +399,40 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
                     return;
                 }
             }
-            operand = if let Ok(operand) = self.ecx.project(&operand, proj_elem) {
-                operand
-            } else {
-                return;
-            }
+            operand =
+                if let Some(operand) = self.ecx.project(&operand, proj_elem).discard_interp_err() {
+                    operand
+                } else {
+                    return;
+                }
         }
 
         self.map.for_each_projection_value(
             place,
             operand,
             &mut |elem, op| match elem {
-                TrackElem::Field(idx) => self.ecx.project_field(op, idx.as_usize()).ok(),
-                TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).ok(),
+                TrackElem::Field(idx) => {
+                    self.ecx.project_field(op, idx.as_usize()).discard_interp_err()
+                }
+                TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).discard_interp_err(),
                 TrackElem::Discriminant => {
-                    let variant = self.ecx.read_discriminant(op).ok()?;
-                    let discr_value =
-                        self.ecx.discriminant_for_variant(op.layout.ty, variant).ok()?;
+                    let variant = self.ecx.read_discriminant(op).discard_interp_err()?;
+                    let discr_value = self
+                        .ecx
+                        .discriminant_for_variant(op.layout.ty, variant)
+                        .discard_interp_err()?;
                     Some(discr_value.into())
                 }
                 TrackElem::DerefLen => {
-                    let op: OpTy<'_> = self.ecx.deref_pointer(op).ok()?.into();
-                    let len_usize = op.len(&self.ecx).ok()?;
+                    let op: OpTy<'_> = self.ecx.deref_pointer(op).discard_interp_err()?.into();
+                    let len_usize = op.len(&self.ecx).discard_interp_err()?;
                     let layout =
                         self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).unwrap();
                     Some(ImmTy::from_uint(len_usize, layout).into())
                 }
             },
             &mut |place, op| {
-                if let Ok(imm) = self.ecx.read_immediate_raw(op)
+                if let Some(imm) = self.ecx.read_immediate_raw(op).discard_interp_err()
                     && let Some(imm) = imm.right()
                 {
                     let elem = self.wrap_immediate(*imm);
@@ -447,11 +456,11 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
             (FlatSet::Bottom, _) | (_, FlatSet::Bottom) => (FlatSet::Bottom, FlatSet::Bottom),
             // Both sides are known, do the actual computation.
             (FlatSet::Elem(left), FlatSet::Elem(right)) => {
-                match self.ecx.binary_op(op, &left, &right) {
+                match self.ecx.binary_op(op, &left, &right).discard_interp_err() {
                     // Ideally this would return an Immediate, since it's sometimes
                     // a pair and sometimes not. But as a hack we always return a pair
                     // and just make the 2nd component `Bottom` when it does not exist.
-                    Ok(val) => {
+                    Some(val) => {
                         if matches!(val.layout.abi, Abi::ScalarPair(..)) {
                             let (val, overflow) = val.to_scalar_pair();
                             (FlatSet::Elem(val), FlatSet::Elem(overflow))
@@ -470,7 +479,7 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
                 }
 
                 let arg_scalar = const_arg.to_scalar();
-                let Ok(arg_value) = arg_scalar.to_bits(layout.size) else {
+                let Some(arg_value) = arg_scalar.to_bits(layout.size).discard_interp_err() else {
                     return (FlatSet::Top, FlatSet::Top);
                 };
 
@@ -518,8 +527,10 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
             return None;
         }
         let enum_ty_layout = self.tcx.layout_of(self.param_env.and(enum_ty)).ok()?;
-        let discr_value =
-            self.ecx.discriminant_for_variant(enum_ty_layout.ty, variant_index).ok()?;
+        let discr_value = self
+            .ecx
+            .discriminant_for_variant(enum_ty_layout.ty, variant_index)
+            .discard_interp_err()?;
         Some(discr_value.to_scalar())
     }
 
@@ -573,7 +584,7 @@ impl<'a, 'tcx> Collector<'a, 'tcx> {
         map: &Map<'tcx>,
     ) -> Option<Const<'tcx>> {
         let ty = place.ty(self.local_decls, self.patch.tcx).ty;
-        let layout = ecx.layout_of(ty).ok()?;
+        let layout = ecx.layout_of(ty).discard_interp_err()?;
 
         if layout.is_zst() {
             return Some(Const::zero_sized(ty));
@@ -595,7 +606,7 @@ impl<'a, 'tcx> Collector<'a, 'tcx> {
                 .intern_with_temp_alloc(layout, |ecx, dest| {
                     try_write_constant(ecx, dest, place, ty, state, map)
                 })
-                .ok()?;
+                .discard_interp_err()?;
             return Some(Const::Val(ConstValue::Indirect { alloc_id, offset: Size::ZERO }, ty));
         }
 
@@ -830,7 +841,7 @@ impl<'tcx> MutVisitor<'tcx> for Patch<'tcx> {
         if let PlaceElem::Index(local) = elem {
             let offset = self.before_effect.get(&(location, local.into()))?;
             let offset = offset.try_to_scalar()?;
-            let offset = offset.to_target_usize(&self.tcx).ok()?;
+            let offset = offset.to_target_usize(&self.tcx).discard_interp_err()?;
             let min_length = offset.checked_add(1)?;
             Some(PlaceElem::ConstantIndex { offset, min_length, from_end: false })
         } else {
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs
index f735d08fca5..4dbcc6af9bd 100644
--- a/compiler/rustc_mir_transform/src/gvn.rs
+++ b/compiler/rustc_mir_transform/src/gvn.rs
@@ -87,8 +87,8 @@ use std::borrow::Cow;
 use either::Either;
 use rustc_const_eval::const_eval::DummyMachine;
 use rustc_const_eval::interpret::{
-    ImmTy, Immediate, InterpCx, MemPlaceMeta, MemoryKind, OpTy, Projectable, Scalar,
-    intern_const_alloc_for_constprop,
+    DiscardInterpError, ImmTy, Immediate, InterpCx, MemPlaceMeta, MemoryKind, OpTy, Projectable,
+    Scalar, intern_const_alloc_for_constprop,
 };
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::graph::dominators::Dominators;
@@ -393,7 +393,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             Repeat(..) => return None,
 
             Constant { ref value, disambiguator: _ } => {
-                self.ecx.eval_mir_constant(value, DUMMY_SP, None).ok()?
+                self.ecx.eval_mir_constant(value, DUMMY_SP, None).discard_interp_err()?
             }
             Aggregate(kind, variant, ref fields) => {
                 let fields = fields
@@ -414,34 +414,39 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                     AggregateTy::RawPtr { output_pointer_ty, .. } => output_pointer_ty,
                 };
                 let variant = if ty.is_enum() { Some(variant) } else { None };
-                let ty = self.ecx.layout_of(ty).ok()?;
+                let ty = self.ecx.layout_of(ty).discard_interp_err()?;
                 if ty.is_zst() {
                     ImmTy::uninit(ty).into()
                 } else if matches!(kind, AggregateTy::RawPtr { .. }) {
                     // Pointers don't have fields, so don't `project_field` them.
-                    let data = self.ecx.read_pointer(fields[0]).ok()?;
+                    let data = self.ecx.read_pointer(fields[0]).discard_interp_err()?;
                     let meta = if fields[1].layout.is_zst() {
                         MemPlaceMeta::None
                     } else {
-                        MemPlaceMeta::Meta(self.ecx.read_scalar(fields[1]).ok()?)
+                        MemPlaceMeta::Meta(self.ecx.read_scalar(fields[1]).discard_interp_err()?)
                     };
                     let ptr_imm = Immediate::new_pointer_with_meta(data, meta, &self.ecx);
                     ImmTy::from_immediate(ptr_imm, ty).into()
                 } else if matches!(ty.abi, Abi::Scalar(..) | Abi::ScalarPair(..)) {
-                    let dest = self.ecx.allocate(ty, MemoryKind::Stack).ok()?;
+                    let dest = self.ecx.allocate(ty, MemoryKind::Stack).discard_interp_err()?;
                     let variant_dest = if let Some(variant) = variant {
-                        self.ecx.project_downcast(&dest, variant).ok()?
+                        self.ecx.project_downcast(&dest, variant).discard_interp_err()?
                     } else {
                         dest.clone()
                     };
                     for (field_index, op) in fields.into_iter().enumerate() {
-                        let field_dest = self.ecx.project_field(&variant_dest, field_index).ok()?;
-                        self.ecx.copy_op(op, &field_dest).ok()?;
+                        let field_dest = self
+                            .ecx
+                            .project_field(&variant_dest, field_index)
+                            .discard_interp_err()?;
+                        self.ecx.copy_op(op, &field_dest).discard_interp_err()?;
                     }
-                    self.ecx.write_discriminant(variant.unwrap_or(FIRST_VARIANT), &dest).ok()?;
+                    self.ecx
+                        .write_discriminant(variant.unwrap_or(FIRST_VARIANT), &dest)
+                        .discard_interp_err()?;
                     self.ecx
                         .alloc_mark_immutable(dest.ptr().provenance.unwrap().alloc_id())
-                        .ok()?;
+                        .discard_interp_err()?;
                     dest.into()
                 } else {
                     return None;
@@ -467,7 +472,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                     // This should have been replaced by a `ConstantIndex` earlier.
                     ProjectionElem::Index(_) => return None,
                 };
-                self.ecx.project(value, elem).ok()?
+                self.ecx.project(value, elem).discard_interp_err()?
             }
             Address { place, kind, provenance: _ } => {
                 if !place.is_indirect_first_projection() {
@@ -475,14 +480,14 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                 }
                 let local = self.locals[place.local]?;
                 let pointer = self.evaluated[local].as_ref()?;
-                let mut mplace = self.ecx.deref_pointer(pointer).ok()?;
+                let mut mplace = self.ecx.deref_pointer(pointer).discard_interp_err()?;
                 for proj in place.projection.iter().skip(1) {
                     // We have no call stack to associate a local with a value, so we cannot
                     // interpret indexing.
                     if matches!(proj, ProjectionElem::Index(_)) {
                         return None;
                     }
-                    mplace = self.ecx.project(&mplace, proj).ok()?;
+                    mplace = self.ecx.project(&mplace, proj).discard_interp_err()?;
                 }
                 let pointer = mplace.to_ref(&self.ecx);
                 let ty = match kind {
@@ -494,26 +499,28 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                     ),
                     AddressKind::Address(mutbl) => Ty::new_ptr(self.tcx, mplace.layout.ty, mutbl),
                 };
-                let layout = self.ecx.layout_of(ty).ok()?;
+                let layout = self.ecx.layout_of(ty).discard_interp_err()?;
                 ImmTy::from_immediate(pointer, layout).into()
             }
 
             Discriminant(base) => {
                 let base = self.evaluated[base].as_ref()?;
-                let variant = self.ecx.read_discriminant(base).ok()?;
-                let discr_value =
-                    self.ecx.discriminant_for_variant(base.layout.ty, variant).ok()?;
+                let variant = self.ecx.read_discriminant(base).discard_interp_err()?;
+                let discr_value = self
+                    .ecx
+                    .discriminant_for_variant(base.layout.ty, variant)
+                    .discard_interp_err()?;
                 discr_value.into()
             }
             Len(slice) => {
                 let slice = self.evaluated[slice].as_ref()?;
                 let usize_layout = self.ecx.layout_of(self.tcx.types.usize).unwrap();
-                let len = slice.len(&self.ecx).ok()?;
+                let len = slice.len(&self.ecx).discard_interp_err()?;
                 let imm = ImmTy::from_uint(len, usize_layout);
                 imm.into()
             }
             NullaryOp(null_op, ty) => {
-                let layout = self.ecx.layout_of(ty).ok()?;
+                let layout = self.ecx.layout_of(ty).discard_interp_err()?;
                 if let NullOp::SizeOf | NullOp::AlignOf = null_op
                     && layout.is_unsized()
                 {
@@ -535,36 +542,36 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             }
             UnaryOp(un_op, operand) => {
                 let operand = self.evaluated[operand].as_ref()?;
-                let operand = self.ecx.read_immediate(operand).ok()?;
-                let val = self.ecx.unary_op(un_op, &operand).ok()?;
+                let operand = self.ecx.read_immediate(operand).discard_interp_err()?;
+                let val = self.ecx.unary_op(un_op, &operand).discard_interp_err()?;
                 val.into()
             }
             BinaryOp(bin_op, lhs, rhs) => {
                 let lhs = self.evaluated[lhs].as_ref()?;
-                let lhs = self.ecx.read_immediate(lhs).ok()?;
+                let lhs = self.ecx.read_immediate(lhs).discard_interp_err()?;
                 let rhs = self.evaluated[rhs].as_ref()?;
-                let rhs = self.ecx.read_immediate(rhs).ok()?;
-                let val = self.ecx.binary_op(bin_op, &lhs, &rhs).ok()?;
+                let rhs = self.ecx.read_immediate(rhs).discard_interp_err()?;
+                let val = self.ecx.binary_op(bin_op, &lhs, &rhs).discard_interp_err()?;
                 val.into()
             }
             Cast { kind, value, from: _, to } => match kind {
                 CastKind::IntToInt | CastKind::IntToFloat => {
                     let value = self.evaluated[value].as_ref()?;
-                    let value = self.ecx.read_immediate(value).ok()?;
-                    let to = self.ecx.layout_of(to).ok()?;
-                    let res = self.ecx.int_to_int_or_float(&value, to).ok()?;
+                    let value = self.ecx.read_immediate(value).discard_interp_err()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let res = self.ecx.int_to_int_or_float(&value, to).discard_interp_err()?;
                     res.into()
                 }
                 CastKind::FloatToFloat | CastKind::FloatToInt => {
                     let value = self.evaluated[value].as_ref()?;
-                    let value = self.ecx.read_immediate(value).ok()?;
-                    let to = self.ecx.layout_of(to).ok()?;
-                    let res = self.ecx.float_to_float_or_int(&value, to).ok()?;
+                    let value = self.ecx.read_immediate(value).discard_interp_err()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let res = self.ecx.float_to_float_or_int(&value, to).discard_interp_err()?;
                     res.into()
                 }
                 CastKind::Transmute => {
                     let value = self.evaluated[value].as_ref()?;
-                    let to = self.ecx.layout_of(to).ok()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
                     // `offset` for immediates only supports scalar/scalar-pair ABIs,
                     // so bail out if the target is not one.
                     if value.as_mplace_or_imm().is_right() {
@@ -574,29 +581,29 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                             _ => return None,
                         }
                     }
-                    value.offset(Size::ZERO, to, &self.ecx).ok()?
+                    value.offset(Size::ZERO, to, &self.ecx).discard_interp_err()?
                 }
                 CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize, _) => {
                     let src = self.evaluated[value].as_ref()?;
-                    let to = self.ecx.layout_of(to).ok()?;
-                    let dest = self.ecx.allocate(to, MemoryKind::Stack).ok()?;
-                    self.ecx.unsize_into(src, to, &dest.clone().into()).ok()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let dest = self.ecx.allocate(to, MemoryKind::Stack).discard_interp_err()?;
+                    self.ecx.unsize_into(src, to, &dest.clone().into()).discard_interp_err()?;
                     self.ecx
                         .alloc_mark_immutable(dest.ptr().provenance.unwrap().alloc_id())
-                        .ok()?;
+                        .discard_interp_err()?;
                     dest.into()
                 }
                 CastKind::FnPtrToPtr | CastKind::PtrToPtr => {
                     let src = self.evaluated[value].as_ref()?;
-                    let src = self.ecx.read_immediate(src).ok()?;
-                    let to = self.ecx.layout_of(to).ok()?;
-                    let ret = self.ecx.ptr_to_ptr(&src, to).ok()?;
+                    let src = self.ecx.read_immediate(src).discard_interp_err()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let ret = self.ecx.ptr_to_ptr(&src, to).discard_interp_err()?;
                     ret.into()
                 }
                 CastKind::PointerCoercion(ty::adjustment::PointerCoercion::UnsafeFnPointer, _) => {
                     let src = self.evaluated[value].as_ref()?;
-                    let src = self.ecx.read_immediate(src).ok()?;
-                    let to = self.ecx.layout_of(to).ok()?;
+                    let src = self.ecx.read_immediate(src).discard_interp_err()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
                     ImmTy::from_immediate(*src, to).into()
                 }
                 _ => return None,
@@ -708,7 +715,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                 && let Some(idx) = self.locals[idx_local]
             {
                 if let Some(offset) = self.evaluated[idx].as_ref()
-                    && let Ok(offset) = self.ecx.read_target_usize(offset)
+                    && let Some(offset) = self.ecx.read_target_usize(offset).discard_interp_err()
                     && let Some(min_length) = offset.checked_add(1)
                 {
                     projection.to_mut()[i] =
@@ -868,7 +875,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             && let DefKind::Enum = self.tcx.def_kind(enum_did)
         {
             let enum_ty = self.tcx.type_of(enum_did).instantiate(self.tcx, enum_args);
-            let discr = self.ecx.discriminant_for_variant(enum_ty, variant).ok()?;
+            let discr = self.ecx.discriminant_for_variant(enum_ty, variant).discard_interp_err()?;
             return Some(self.insert_scalar(discr.to_scalar(), discr.layout.ty));
         }
 
@@ -1218,13 +1225,13 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             return None;
         }
 
-        let layout = self.ecx.layout_of(lhs_ty).ok()?;
+        let layout = self.ecx.layout_of(lhs_ty).discard_interp_err()?;
 
         let as_bits = |value| {
             let constant = self.evaluated[value].as_ref()?;
             if layout.abi.is_scalar() {
-                let scalar = self.ecx.read_scalar(constant).ok()?;
-                scalar.to_bits(constant.layout.size).ok()
+                let scalar = self.ecx.read_scalar(constant).discard_interp_err()?;
+                scalar.to_bits(constant.layout.size).discard_interp_err()
             } else {
                 // `constant` is a wide pointer. Do not evaluate to bits.
                 None
@@ -1484,7 +1491,7 @@ fn op_to_prop_const<'tcx>(
 
     // If this constant has scalar ABI, return it as a `ConstValue::Scalar`.
     if let Abi::Scalar(abi::Scalar::Initialized { .. }) = op.layout.abi
-        && let Ok(scalar) = ecx.read_scalar(op)
+        && let Some(scalar) = ecx.read_scalar(op).discard_interp_err()
     {
         if !scalar.try_to_scalar_int().is_ok() {
             // Check that we do not leak a pointer.
@@ -1498,12 +1505,12 @@ fn op_to_prop_const<'tcx>(
     // If this constant is already represented as an `Allocation`,
     // try putting it into global memory to return it.
     if let Either::Left(mplace) = op.as_mplace_or_imm() {
-        let (size, _align) = ecx.size_and_align_of_mplace(&mplace).ok()??;
+        let (size, _align) = ecx.size_and_align_of_mplace(&mplace).discard_interp_err()??;
 
         // Do not try interning a value that contains provenance.
         // Due to https://github.com/rust-lang/rust/issues/79738, doing so could lead to bugs.
         // FIXME: remove this hack once that issue is fixed.
-        let alloc_ref = ecx.get_ptr_alloc(mplace.ptr(), size).ok()??;
+        let alloc_ref = ecx.get_ptr_alloc(mplace.ptr(), size).discard_interp_err()??;
         if alloc_ref.has_provenance() {
             return None;
         }
@@ -1511,7 +1518,7 @@ fn op_to_prop_const<'tcx>(
         let pointer = mplace.ptr().into_pointer_or_addr().ok()?;
         let (prov, offset) = pointer.into_parts();
         let alloc_id = prov.alloc_id();
-        intern_const_alloc_for_constprop(ecx, alloc_id).ok()?;
+        intern_const_alloc_for_constprop(ecx, alloc_id).discard_interp_err()?;
 
         // `alloc_id` may point to a static. Codegen will choke on an `Indirect` with anything
         // by `GlobalAlloc::Memory`, so do fall through to copying if needed.
@@ -1526,7 +1533,9 @@ fn op_to_prop_const<'tcx>(
     }
 
     // Everything failed: create a new allocation to hold the data.
-    let alloc_id = ecx.intern_with_temp_alloc(op.layout, |ecx, dest| ecx.copy_op(op, dest)).ok()?;
+    let alloc_id = ecx
+        .intern_with_temp_alloc(op.layout, |ecx, dest| ecx.copy_op(op, dest))
+        .discard_interp_err()?;
     let value = ConstValue::Indirect { alloc_id, offset: Size::ZERO };
 
     // Check that we do not leak a pointer.
diff --git a/compiler/rustc_mir_transform/src/jump_threading.rs b/compiler/rustc_mir_transform/src/jump_threading.rs
index 91fbc91e1e7..e69a7e552f6 100644
--- a/compiler/rustc_mir_transform/src/jump_threading.rs
+++ b/compiler/rustc_mir_transform/src/jump_threading.rs
@@ -37,7 +37,9 @@
 
 use rustc_arena::DroplessArena;
 use rustc_const_eval::const_eval::DummyMachine;
-use rustc_const_eval::interpret::{ImmTy, Immediate, InterpCx, OpTy, Projectable};
+use rustc_const_eval::interpret::{
+    DiscardInterpError, ImmTy, Immediate, InterpCx, OpTy, Projectable,
+};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_index::IndexVec;
 use rustc_index::bit_set::BitSet;
@@ -200,7 +202,9 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
         debug!(?discr, ?bb);
 
         let discr_ty = discr.ty(self.body, self.tcx).ty;
-        let Ok(discr_layout) = self.ecx.layout_of(discr_ty) else { return };
+        let Some(discr_layout) = self.ecx.layout_of(discr_ty).discard_interp_err() else {
+            return;
+        };
 
         let Some(discr) = self.map.find(discr.as_ref()) else { return };
         debug!(?discr);
@@ -388,24 +392,28 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
             lhs,
             constant,
             &mut |elem, op| match elem {
-                TrackElem::Field(idx) => self.ecx.project_field(op, idx.as_usize()).ok(),
-                TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).ok(),
+                TrackElem::Field(idx) => {
+                    self.ecx.project_field(op, idx.as_usize()).discard_interp_err()
+                }
+                TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).discard_interp_err(),
                 TrackElem::Discriminant => {
-                    let variant = self.ecx.read_discriminant(op).ok()?;
-                    let discr_value =
-                        self.ecx.discriminant_for_variant(op.layout.ty, variant).ok()?;
+                    let variant = self.ecx.read_discriminant(op).discard_interp_err()?;
+                    let discr_value = self
+                        .ecx
+                        .discriminant_for_variant(op.layout.ty, variant)
+                        .discard_interp_err()?;
                     Some(discr_value.into())
                 }
                 TrackElem::DerefLen => {
-                    let op: OpTy<'_> = self.ecx.deref_pointer(op).ok()?.into();
-                    let len_usize = op.len(&self.ecx).ok()?;
+                    let op: OpTy<'_> = self.ecx.deref_pointer(op).discard_interp_err()?.into();
+                    let len_usize = op.len(&self.ecx).discard_interp_err()?;
                     let layout = self.ecx.layout_of(self.tcx.types.usize).unwrap();
                     Some(ImmTy::from_uint(len_usize, layout).into())
                 }
             },
             &mut |place, op| {
                 if let Some(conditions) = state.try_get_idx(place, &self.map)
-                    && let Ok(imm) = self.ecx.read_immediate_raw(op)
+                    && let Some(imm) = self.ecx.read_immediate_raw(op).discard_interp_err()
                     && let Some(imm) = imm.right()
                     && let Immediate::Scalar(Scalar::Int(int)) = *imm
                 {
@@ -429,8 +437,10 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
         match rhs {
             // If we expect `lhs ?= A`, we have an opportunity if we assume `constant == A`.
             Operand::Constant(constant) => {
-                let Ok(constant) =
-                    self.ecx.eval_mir_constant(&constant.const_, constant.span, None)
+                let Some(constant) = self
+                    .ecx
+                    .eval_mir_constant(&constant.const_, constant.span, None)
+                    .discard_interp_err()
                 else {
                     return;
                 };
@@ -469,8 +479,10 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
                     AggregateKind::Adt(.., Some(_)) => return,
                     AggregateKind::Adt(_, variant_index, ..) if agg_ty.is_enum() => {
                         if let Some(discr_target) = self.map.apply(lhs, TrackElem::Discriminant)
-                            && let Ok(discr_value) =
-                                self.ecx.discriminant_for_variant(agg_ty, *variant_index)
+                            && let Some(discr_value) = self
+                                .ecx
+                                .discriminant_for_variant(agg_ty, *variant_index)
+                                .discard_interp_err()
                         {
                             self.process_immediate(bb, discr_target, discr_value, state);
                         }
@@ -555,7 +567,9 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
                 // `SetDiscriminant` may be a no-op if the assigned variant is the untagged variant
                 // of a niche encoding. If we cannot ensure that we write to the discriminant, do
                 // nothing.
-                let Ok(enum_layout) = self.ecx.layout_of(enum_ty) else { return };
+                let Some(enum_layout) = self.ecx.layout_of(enum_ty).discard_interp_err() else {
+                    return;
+                };
                 let writes_discriminant = match enum_layout.variants {
                     Variants::Single { index } => {
                         assert_eq!(index, *variant_index);
@@ -568,7 +582,10 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
                     } => *variant_index != untagged_variant,
                 };
                 if writes_discriminant {
-                    let Ok(discr) = self.ecx.discriminant_for_variant(enum_ty, *variant_index)
+                    let Some(discr) = self
+                        .ecx
+                        .discriminant_for_variant(enum_ty, *variant_index)
+                        .discard_interp_err()
                     else {
                         return;
                     };
@@ -645,7 +662,9 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
 
         let Some(discr) = discr.place() else { return };
         let discr_ty = discr.ty(self.body, self.tcx).ty;
-        let Ok(discr_layout) = self.ecx.layout_of(discr_ty) else { return };
+        let Some(discr_layout) = self.ecx.layout_of(discr_ty).discard_interp_err() else {
+            return;
+        };
         let Some(conditions) = state.try_get(discr.as_ref(), &self.map) else { return };
 
         if let Some((value, _)) = targets.iter().find(|&(_, target)| target == target_bb) {
diff --git a/compiler/rustc_mir_transform/src/known_panics_lint.rs b/compiler/rustc_mir_transform/src/known_panics_lint.rs
index 783e7aabe85..b165ea53440 100644
--- a/compiler/rustc_mir_transform/src/known_panics_lint.rs
+++ b/compiler/rustc_mir_transform/src/known_panics_lint.rs
@@ -6,7 +6,7 @@ use std::fmt::Debug;
 
 use rustc_const_eval::const_eval::DummyMachine;
 use rustc_const_eval::interpret::{
-    ImmTy, InterpCx, InterpResult, Projectable, Scalar, format_interp_error,
+    DiscardInterpError, ImmTy, InterpCx, InterpResult, Projectable, Scalar, format_interp_error,
 };
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::HirId;
@@ -101,7 +101,8 @@ impl<'tcx> Value<'tcx> {
                 }
                 (PlaceElem::Index(idx), Value::Aggregate { fields, .. }) => {
                     let idx = prop.get_const(idx.into())?.immediate()?;
-                    let idx = prop.ecx.read_target_usize(idx).ok()?.try_into().ok()?;
+                    let idx =
+                        prop.ecx.read_target_usize(idx).discard_interp_err()?.try_into().ok()?;
                     if idx <= FieldIdx::MAX_AS_U32 {
                         fields.get(FieldIdx::from_u32(idx)).unwrap_or(&Value::Uninit)
                     } else {
@@ -243,6 +244,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                     "known panics lint encountered formatting error: {}",
                     format_interp_error(self.ecx.tcx.dcx(), error),
                 );
+                error.discard_interp_err();
                 None
             }
         }
@@ -347,9 +349,9 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             // We need the type of the LHS. We cannot use `place_layout` as that is the type
             // of the result, which for checked binops is not the same!
             let left_ty = left.ty(self.local_decls(), self.tcx);
-            let left_size = self.ecx.layout_of(left_ty).ok()?.size;
+            let left_size = self.ecx.layout_of(left_ty).discard_interp_err()?.size;
             let right_size = r.layout.size;
-            let r_bits = r.to_scalar().to_bits(right_size).ok();
+            let r_bits = r.to_scalar().to_bits(right_size).discard_interp_err();
             if r_bits.is_some_and(|b| b >= left_size.bits() as u128) {
                 debug!("check_binary_op: reporting assert for {:?}", location);
                 let panic = AssertKind::Overflow(
@@ -496,7 +498,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                 // This can be `None` if the lhs wasn't const propagated and we just
                 // triggered the assert on the value of the rhs.
                 self.eval_operand(op)
-                    .and_then(|op| self.ecx.read_immediate(&op).ok())
+                    .and_then(|op| self.ecx.read_immediate(&op).discard_interp_err())
                     .map_or(DbgVal::Underscore, |op| DbgVal::Val(op.to_const_int()))
             };
             let msg = match msg {
@@ -540,7 +542,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
         use rustc_middle::mir::Rvalue::*;
-        let layout = self.ecx.layout_of(dest.ty(self.body, self.tcx).ty).ok()?;
+        let layout = self.ecx.layout_of(dest.ty(self.body, self.tcx).ty).discard_interp_err()?;
         trace!(?layout);
 
         let val: Value<'_> = match *rvalue {
@@ -602,7 +604,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
 
             Len(place) => {
                 let len = match self.get_const(place)? {
-                    Value::Immediate(src) => src.len(&self.ecx).ok()?,
+                    Value::Immediate(src) => src.len(&self.ecx).discard_interp_err()?,
                     Value::Aggregate { fields, .. } => fields.len() as u64,
                     Value::Uninit => match place.ty(self.local_decls(), self.tcx).ty.kind() {
                         ty::Array(_, n) => n.try_eval_target_usize(self.tcx, self.param_env)?,
@@ -633,21 +635,21 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             Cast(ref kind, ref value, to) => match kind {
                 CastKind::IntToInt | CastKind::IntToFloat => {
                     let value = self.eval_operand(value)?;
-                    let value = self.ecx.read_immediate(&value).ok()?;
-                    let to = self.ecx.layout_of(to).ok()?;
-                    let res = self.ecx.int_to_int_or_float(&value, to).ok()?;
+                    let value = self.ecx.read_immediate(&value).discard_interp_err()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let res = self.ecx.int_to_int_or_float(&value, to).discard_interp_err()?;
                     res.into()
                 }
                 CastKind::FloatToFloat | CastKind::FloatToInt => {
                     let value = self.eval_operand(value)?;
-                    let value = self.ecx.read_immediate(&value).ok()?;
-                    let to = self.ecx.layout_of(to).ok()?;
-                    let res = self.ecx.float_to_float_or_int(&value, to).ok()?;
+                    let value = self.ecx.read_immediate(&value).discard_interp_err()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let res = self.ecx.float_to_float_or_int(&value, to).discard_interp_err()?;
                     res.into()
                 }
                 CastKind::Transmute => {
                     let value = self.eval_operand(value)?;
-                    let to = self.ecx.layout_of(to).ok()?;
+                    let to = self.ecx.layout_of(to).discard_interp_err()?;
                     // `offset` for immediates only supports scalar/scalar-pair ABIs,
                     // so bail out if the target is not one.
                     match (value.layout.abi, to.abi) {
@@ -656,7 +658,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                         _ => return None,
                     }
 
-                    value.offset(Size::ZERO, to, &self.ecx).ok()?.into()
+                    value.offset(Size::ZERO, to, &self.ecx).discard_interp_err()?.into()
                 }
                 _ => return None,
             },
@@ -781,7 +783,8 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
             TerminatorKind::SwitchInt { ref discr, ref targets } => {
                 if let Some(ref value) = self.eval_operand(discr)
                     && let Some(value_const) = self.use_ecx(|this| this.ecx.read_scalar(value))
-                    && let Ok(constant) = value_const.to_bits(value_const.size())
+                    && let Some(constant) =
+                        value_const.to_bits(value_const.size()).discard_interp_err()
                 {
                     // We managed to evaluate the discriminant, so we know we only need to visit
                     // one target.
diff --git a/src/tools/miri/src/concurrency/data_race.rs b/src/tools/miri/src/concurrency/data_race.rs
index d1cd15aab3d..5910be22a69 100644
--- a/src/tools/miri/src/concurrency/data_race.rs
+++ b/src/tools/miri/src/concurrency/data_race.rs
@@ -641,7 +641,7 @@ pub trait EvalContextExt<'tcx>: MiriInterpCxExt<'tcx> {
         // The program didn't actually do a read, so suppress the memory access hooks.
         // This is also a very special exception where we just ignore an error -- if this read
         // was UB e.g. because the memory is uninitialized, we don't want to know!
-        let old_val = this.run_for_validation(|this| this.read_scalar(dest)).ok();
+        let old_val = this.run_for_validation(|this| this.read_scalar(dest)).discard_interp_err();
         this.allow_data_races_mut(move |this| this.write_scalar(val, dest))?;
         this.validate_atomic_store(dest, atomic)?;
         this.buffered_atomic_write(val, dest, atomic, old_val)
diff --git a/src/tools/miri/src/diagnostics.rs b/src/tools/miri/src/diagnostics.rs
index 4445550512b..ee087ece9d8 100644
--- a/src/tools/miri/src/diagnostics.rs
+++ b/src/tools/miri/src/diagnostics.rs
@@ -223,7 +223,10 @@ pub fn report_error<'tcx>(
         let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
         use TerminationInfo::*;
         let title = match info {
-            Exit { code, leak_check } => return Some((*code, *leak_check)),
+            &Exit { code, leak_check } => {
+                e.discard_interp_err();
+                return Some((code, leak_check));
+            }
             Abort(_) => Some("abnormal termination"),
             UnsupportedInIsolation(_) | Int2PtrWithStrictProvenance | UnsupportedForeignItem(_) =>
                 Some("unsupported operation"),
@@ -375,6 +378,7 @@ pub fn report_error<'tcx>(
                 InvalidProgramInfo::AlreadyReported(_)
             ) => {
                 // This got already reported. No point in reporting it again.
+                e.discard_interp_err();
                 return None;
             }
             _ =>
diff --git a/src/tools/miri/src/intrinsics/simd.rs b/src/tools/miri/src/intrinsics/simd.rs
index 802a70e5a54..7f43c61cd66 100644
--- a/src/tools/miri/src/intrinsics/simd.rs
+++ b/src/tools/miri/src/intrinsics/simd.rs
@@ -247,7 +247,8 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                             // This does NaN adjustments.
                             let val = this.binary_op(mir_op, &left, &right).map_err(|err| {
                                 match err.kind() {
-                                    InterpError::UndefinedBehavior(UndefinedBehaviorInfo::ShiftOverflow { shift_amount, .. }) => {
+                                    &InterpError::UndefinedBehavior(UndefinedBehaviorInfo::ShiftOverflow { shift_amount, .. }) => {
+                                        err.discard_interp_err();
                                         // This resets the interpreter backtrace, but it's not worth avoiding that.
                                         let shift_amount = match shift_amount {
                                             Either::Left(v) => v.to_string(),