make InterpResult a dedicated type to avoid accidentally discarding the error

4 files changed, 127 insertions, 152 deletions

diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index 905143b2efb..002216f50f2 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -4,7 +4,7 @@
 
 use rustc_const_eval::const_eval::{DummyMachine, throw_machine_stop_str};
 use rustc_const_eval::interpret::{
-    DiscardInterpError, ImmTy, Immediate, InterpCx, OpTy, PlaceTy, Projectable,
+    ImmTy, Immediate, InterpCx, OpTy, PlaceTy, Projectable, interp_ok,
 };
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::DefKind;
@@ -238,6 +238,7 @@ impl<'tcx> ValueAnalysis<'tcx> for ConstAnalysis<'_, 'tcx> {
                     FlatSet::Elem(op) => self
                         .ecx
                         .int_to_int_or_float(&op, layout)
+                        .discard_err()
                         .map_or(FlatSet::Top, |result| self.wrap_immediate(*result)),
                     FlatSet::Bottom => FlatSet::Bottom,
                     FlatSet::Top => FlatSet::Top,
@@ -251,6 +252,7 @@ impl<'tcx> ValueAnalysis<'tcx> for ConstAnalysis<'_, 'tcx> {
                     FlatSet::Elem(op) => self
                         .ecx
                         .float_to_float_or_int(&op, layout)
+                        .discard_err()
                         .map_or(FlatSet::Top, |result| self.wrap_immediate(*result)),
                     FlatSet::Bottom => FlatSet::Bottom,
                     FlatSet::Top => FlatSet::Top,
@@ -273,6 +275,7 @@ impl<'tcx> ValueAnalysis<'tcx> for ConstAnalysis<'_, 'tcx> {
                 FlatSet::Elem(value) => self
                     .ecx
                     .unary_op(*op, &value)
+                    .discard_err()
                     .map_or(FlatSet::Top, |val| self.wrap_immediate(*val)),
                 FlatSet::Bottom => FlatSet::Bottom,
                 FlatSet::Top => FlatSet::Top,
@@ -366,10 +369,8 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
                 }
             }
             Operand::Constant(box constant) => {
-                if let Some(constant) = self
-                    .ecx
-                    .eval_mir_constant(&constant.const_, constant.span, None)
-                    .discard_interp_err()
+                if let Some(constant) =
+                    self.ecx.eval_mir_constant(&constant.const_, constant.span, None).discard_err()
                 {
                     self.assign_constant(state, place, constant, &[]);
                 }
@@ -391,7 +392,7 @@ 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 Some(offset) = index.to_target_usize(&self.tcx).discard_interp_err()
+                    && let Some(offset) = index.to_target_usize(&self.tcx).discard_err()
                     && let Some(min_length) = offset.checked_add(1)
                 {
                     proj_elem = PlaceElem::ConstantIndex { offset, min_length, from_end: false };
@@ -399,40 +400,35 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
                     return;
                 }
             }
-            operand =
-                if let Some(operand) = self.ecx.project(&operand, proj_elem).discard_interp_err() {
-                    operand
-                } else {
-                    return;
-                }
+            operand = if let Some(operand) = self.ecx.project(&operand, proj_elem).discard_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()).discard_interp_err()
-                }
-                TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).discard_interp_err(),
+                TrackElem::Field(idx) => self.ecx.project_field(op, idx.as_usize()).discard_err(),
+                TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).discard_err(),
                 TrackElem::Discriminant => {
-                    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()?;
+                    let variant = self.ecx.read_discriminant(op).discard_err()?;
+                    let discr_value =
+                        self.ecx.discriminant_for_variant(op.layout.ty, variant).discard_err()?;
                     Some(discr_value.into())
                 }
                 TrackElem::DerefLen => {
-                    let op: OpTy<'_> = self.ecx.deref_pointer(op).discard_interp_err()?.into();
-                    let len_usize = op.len(&self.ecx).discard_interp_err()?;
+                    let op: OpTy<'_> = self.ecx.deref_pointer(op).discard_err()?.into();
+                    let len_usize = op.len(&self.ecx).discard_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 Some(imm) = self.ecx.read_immediate_raw(op).discard_interp_err()
+                if let Some(imm) = self.ecx.read_immediate_raw(op).discard_err()
                     && let Some(imm) = imm.right()
                 {
                     let elem = self.wrap_immediate(*imm);
@@ -456,7 +452,7 @@ 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).discard_interp_err() {
+                match self.ecx.binary_op(op, &left, &right).discard_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.
@@ -479,7 +475,7 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
                 }
 
                 let arg_scalar = const_arg.to_scalar();
-                let Some(arg_value) = arg_scalar.to_bits(layout.size).discard_interp_err() else {
+                let Some(arg_value) = arg_scalar.to_bits(layout.size).discard_err() else {
                     return (FlatSet::Top, FlatSet::Top);
                 };
 
@@ -527,10 +523,8 @@ 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)
-            .discard_interp_err()?;
+        let discr_value =
+            self.ecx.discriminant_for_variant(enum_ty_layout.ty, variant_index).discard_err()?;
         Some(discr_value.to_scalar())
     }
 
@@ -584,7 +578,7 @@ 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).discard_interp_err()?;
+        let layout = ecx.layout_of(ty).ok()?;
 
         if layout.is_zst() {
             return Some(Const::zero_sized(ty));
@@ -606,7 +600,7 @@ impl<'a, 'tcx> Collector<'a, 'tcx> {
                 .intern_with_temp_alloc(layout, |ecx, dest| {
                     try_write_constant(ecx, dest, place, ty, state, map)
                 })
-                .discard_interp_err()?;
+                .discard_err()?;
             return Some(Const::Val(ConstValue::Indirect { alloc_id, offset: Size::ZERO }, ty));
         }
 
@@ -643,7 +637,7 @@ fn try_write_constant<'tcx>(
 
     // Fast path for ZSTs.
     if layout.is_zst() {
-        return Ok(());
+        return interp_ok(());
     }
 
     // Fast path for scalars.
@@ -728,7 +722,7 @@ fn try_write_constant<'tcx>(
         ty::Error(_) | ty::Infer(..) | ty::CoroutineWitness(..) => bug!(),
     }
 
-    Ok(())
+    interp_ok(())
 }
 
 impl<'mir, 'tcx>
@@ -841,7 +835,7 @@ 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).discard_interp_err()?;
+            let offset = offset.to_target_usize(&self.tcx).discard_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 4dbcc6af9bd..50c9702cb9b 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::{
-    DiscardInterpError, ImmTy, Immediate, InterpCx, MemPlaceMeta, MemoryKind, OpTy, Projectable,
-    Scalar, intern_const_alloc_for_constprop,
+    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).discard_interp_err()?
+                self.ecx.eval_mir_constant(value, DUMMY_SP, None).discard_err()?
             }
             Aggregate(kind, variant, ref fields) => {
                 let fields = fields
@@ -414,39 +414,37 @@ 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).discard_interp_err()?;
+                let ty = self.ecx.layout_of(ty).ok()?;
                 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]).discard_interp_err()?;
+                    let data = self.ecx.read_pointer(fields[0]).discard_err()?;
                     let meta = if fields[1].layout.is_zst() {
                         MemPlaceMeta::None
                     } else {
-                        MemPlaceMeta::Meta(self.ecx.read_scalar(fields[1]).discard_interp_err()?)
+                        MemPlaceMeta::Meta(self.ecx.read_scalar(fields[1]).discard_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).discard_interp_err()?;
+                    let dest = self.ecx.allocate(ty, MemoryKind::Stack).discard_err()?;
                     let variant_dest = if let Some(variant) = variant {
-                        self.ecx.project_downcast(&dest, variant).discard_interp_err()?
+                        self.ecx.project_downcast(&dest, variant).discard_err()?
                     } else {
                         dest.clone()
                     };
                     for (field_index, op) in fields.into_iter().enumerate() {
-                        let field_dest = self
-                            .ecx
-                            .project_field(&variant_dest, field_index)
-                            .discard_interp_err()?;
-                        self.ecx.copy_op(op, &field_dest).discard_interp_err()?;
+                        let field_dest =
+                            self.ecx.project_field(&variant_dest, field_index).discard_err()?;
+                        self.ecx.copy_op(op, &field_dest).discard_err()?;
                     }
                     self.ecx
                         .write_discriminant(variant.unwrap_or(FIRST_VARIANT), &dest)
-                        .discard_interp_err()?;
+                        .discard_err()?;
                     self.ecx
                         .alloc_mark_immutable(dest.ptr().provenance.unwrap().alloc_id())
-                        .discard_interp_err()?;
+                        .discard_err()?;
                     dest.into()
                 } else {
                     return None;
@@ -472,7 +470,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                     // This should have been replaced by a `ConstantIndex` earlier.
                     ProjectionElem::Index(_) => return None,
                 };
-                self.ecx.project(value, elem).discard_interp_err()?
+                self.ecx.project(value, elem).discard_err()?
             }
             Address { place, kind, provenance: _ } => {
                 if !place.is_indirect_first_projection() {
@@ -480,14 +478,14 @@ 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).discard_interp_err()?;
+                let mut mplace = self.ecx.deref_pointer(pointer).discard_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).discard_interp_err()?;
+                    mplace = self.ecx.project(&mplace, proj).discard_err()?;
                 }
                 let pointer = mplace.to_ref(&self.ecx);
                 let ty = match kind {
@@ -499,28 +497,26 @@ 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).discard_interp_err()?;
+                let layout = self.ecx.layout_of(ty).ok()?;
                 ImmTy::from_immediate(pointer, layout).into()
             }
 
             Discriminant(base) => {
                 let base = self.evaluated[base].as_ref()?;
-                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()?;
+                let variant = self.ecx.read_discriminant(base).discard_err()?;
+                let discr_value =
+                    self.ecx.discriminant_for_variant(base.layout.ty, variant).discard_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).discard_interp_err()?;
+                let len = slice.len(&self.ecx).discard_err()?;
                 let imm = ImmTy::from_uint(len, usize_layout);
                 imm.into()
             }
             NullaryOp(null_op, ty) => {
-                let layout = self.ecx.layout_of(ty).discard_interp_err()?;
+                let layout = self.ecx.layout_of(ty).ok()?;
                 if let NullOp::SizeOf | NullOp::AlignOf = null_op
                     && layout.is_unsized()
                 {
@@ -542,36 +538,36 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             }
             UnaryOp(un_op, operand) => {
                 let operand = self.evaluated[operand].as_ref()?;
-                let operand = self.ecx.read_immediate(operand).discard_interp_err()?;
-                let val = self.ecx.unary_op(un_op, &operand).discard_interp_err()?;
+                let operand = self.ecx.read_immediate(operand).discard_err()?;
+                let val = self.ecx.unary_op(un_op, &operand).discard_err()?;
                 val.into()
             }
             BinaryOp(bin_op, lhs, rhs) => {
                 let lhs = self.evaluated[lhs].as_ref()?;
-                let lhs = self.ecx.read_immediate(lhs).discard_interp_err()?;
+                let lhs = self.ecx.read_immediate(lhs).discard_err()?;
                 let rhs = self.evaluated[rhs].as_ref()?;
-                let rhs = self.ecx.read_immediate(rhs).discard_interp_err()?;
-                let val = self.ecx.binary_op(bin_op, &lhs, &rhs).discard_interp_err()?;
+                let rhs = self.ecx.read_immediate(rhs).discard_err()?;
+                let val = self.ecx.binary_op(bin_op, &lhs, &rhs).discard_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).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()?;
+                    let value = self.ecx.read_immediate(value).discard_err()?;
+                    let to = self.ecx.layout_of(to).ok()?;
+                    let res = self.ecx.int_to_int_or_float(&value, to).discard_err()?;
                     res.into()
                 }
                 CastKind::FloatToFloat | CastKind::FloatToInt => {
                     let value = self.evaluated[value].as_ref()?;
-                    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()?;
+                    let value = self.ecx.read_immediate(value).discard_err()?;
+                    let to = self.ecx.layout_of(to).ok()?;
+                    let res = self.ecx.float_to_float_or_int(&value, to).discard_err()?;
                     res.into()
                 }
                 CastKind::Transmute => {
                     let value = self.evaluated[value].as_ref()?;
-                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let to = self.ecx.layout_of(to).ok()?;
                     // `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() {
@@ -581,29 +577,29 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                             _ => return None,
                         }
                     }
-                    value.offset(Size::ZERO, to, &self.ecx).discard_interp_err()?
+                    value.offset(Size::ZERO, to, &self.ecx).discard_err()?
                 }
                 CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize, _) => {
                     let src = self.evaluated[value].as_ref()?;
-                    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()?;
+                    let to = self.ecx.layout_of(to).ok()?;
+                    let dest = self.ecx.allocate(to, MemoryKind::Stack).discard_err()?;
+                    self.ecx.unsize_into(src, to, &dest.clone().into()).discard_err()?;
                     self.ecx
                         .alloc_mark_immutable(dest.ptr().provenance.unwrap().alloc_id())
-                        .discard_interp_err()?;
+                        .discard_err()?;
                     dest.into()
                 }
                 CastKind::FnPtrToPtr | CastKind::PtrToPtr => {
                     let src = self.evaluated[value].as_ref()?;
-                    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()?;
+                    let src = self.ecx.read_immediate(src).discard_err()?;
+                    let to = self.ecx.layout_of(to).ok()?;
+                    let ret = self.ecx.ptr_to_ptr(&src, to).discard_err()?;
                     ret.into()
                 }
                 CastKind::PointerCoercion(ty::adjustment::PointerCoercion::UnsafeFnPointer, _) => {
                     let src = self.evaluated[value].as_ref()?;
-                    let src = self.ecx.read_immediate(src).discard_interp_err()?;
-                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let src = self.ecx.read_immediate(src).discard_err()?;
+                    let to = self.ecx.layout_of(to).ok()?;
                     ImmTy::from_immediate(*src, to).into()
                 }
                 _ => return None,
@@ -715,7 +711,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                 && let Some(idx) = self.locals[idx_local]
             {
                 if let Some(offset) = self.evaluated[idx].as_ref()
-                    && let Some(offset) = self.ecx.read_target_usize(offset).discard_interp_err()
+                    && let Some(offset) = self.ecx.read_target_usize(offset).discard_err()
                     && let Some(min_length) = offset.checked_add(1)
                 {
                     projection.to_mut()[i] =
@@ -875,7 +871,7 @@ 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).discard_interp_err()?;
+            let discr = self.ecx.discriminant_for_variant(enum_ty, variant).discard_err()?;
             return Some(self.insert_scalar(discr.to_scalar(), discr.layout.ty));
         }
 
@@ -1225,13 +1221,13 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             return None;
         }
 
-        let layout = self.ecx.layout_of(lhs_ty).discard_interp_err()?;
+        let layout = self.ecx.layout_of(lhs_ty).ok()?;
 
         let as_bits = |value| {
             let constant = self.evaluated[value].as_ref()?;
             if layout.abi.is_scalar() {
-                let scalar = self.ecx.read_scalar(constant).discard_interp_err()?;
-                scalar.to_bits(constant.layout.size).discard_interp_err()
+                let scalar = self.ecx.read_scalar(constant).discard_err()?;
+                scalar.to_bits(constant.layout.size).discard_err()
             } else {
                 // `constant` is a wide pointer. Do not evaluate to bits.
                 None
@@ -1491,7 +1487,7 @@ 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 Some(scalar) = ecx.read_scalar(op).discard_interp_err()
+        && let Some(scalar) = ecx.read_scalar(op).discard_err()
     {
         if !scalar.try_to_scalar_int().is_ok() {
             // Check that we do not leak a pointer.
@@ -1505,12 +1501,12 @@ 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).discard_interp_err()??;
+        let (size, _align) = ecx.size_and_align_of_mplace(&mplace).discard_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).discard_interp_err()??;
+        let alloc_ref = ecx.get_ptr_alloc(mplace.ptr(), size).discard_err()??;
         if alloc_ref.has_provenance() {
             return None;
         }
@@ -1518,7 +1514,7 @@ 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).discard_interp_err()?;
+        intern_const_alloc_for_constprop(ecx, alloc_id).discard_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.
@@ -1533,9 +1529,8 @@ 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))
-        .discard_interp_err()?;
+    let alloc_id =
+        ecx.intern_with_temp_alloc(op.layout, |ecx, dest| ecx.copy_op(op, dest)).discard_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 e69a7e552f6..1844b97887a 100644
--- a/compiler/rustc_mir_transform/src/jump_threading.rs
+++ b/compiler/rustc_mir_transform/src/jump_threading.rs
@@ -37,9 +37,7 @@
 
 use rustc_arena::DroplessArena;
 use rustc_const_eval::const_eval::DummyMachine;
-use rustc_const_eval::interpret::{
-    DiscardInterpError, ImmTy, Immediate, InterpCx, OpTy, Projectable,
-};
+use rustc_const_eval::interpret::{ImmTy, Immediate, InterpCx, OpTy, Projectable};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_index::IndexVec;
 use rustc_index::bit_set::BitSet;
@@ -202,7 +200,7 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
         debug!(?discr, ?bb);
 
         let discr_ty = discr.ty(self.body, self.tcx).ty;
-        let Some(discr_layout) = self.ecx.layout_of(discr_ty).discard_interp_err() else {
+        let Ok(discr_layout) = self.ecx.layout_of(discr_ty) else {
             return;
         };
 
@@ -392,28 +390,24 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
             lhs,
             constant,
             &mut |elem, op| match elem {
-                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::Field(idx) => self.ecx.project_field(op, idx.as_usize()).discard_err(),
+                TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).discard_err(),
                 TrackElem::Discriminant => {
-                    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()?;
+                    let variant = self.ecx.read_discriminant(op).discard_err()?;
+                    let discr_value =
+                        self.ecx.discriminant_for_variant(op.layout.ty, variant).discard_err()?;
                     Some(discr_value.into())
                 }
                 TrackElem::DerefLen => {
-                    let op: OpTy<'_> = self.ecx.deref_pointer(op).discard_interp_err()?.into();
-                    let len_usize = op.len(&self.ecx).discard_interp_err()?;
+                    let op: OpTy<'_> = self.ecx.deref_pointer(op).discard_err()?.into();
+                    let len_usize = op.len(&self.ecx).discard_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 Some(imm) = self.ecx.read_immediate_raw(op).discard_interp_err()
+                    && let Some(imm) = self.ecx.read_immediate_raw(op).discard_err()
                     && let Some(imm) = imm.right()
                     && let Immediate::Scalar(Scalar::Int(int)) = *imm
                 {
@@ -437,10 +431,8 @@ 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 Some(constant) = self
-                    .ecx
-                    .eval_mir_constant(&constant.const_, constant.span, None)
-                    .discard_interp_err()
+                let Some(constant) =
+                    self.ecx.eval_mir_constant(&constant.const_, constant.span, None).discard_err()
                 else {
                     return;
                 };
@@ -482,7 +474,7 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
                             && let Some(discr_value) = self
                                 .ecx
                                 .discriminant_for_variant(agg_ty, *variant_index)
-                                .discard_interp_err()
+                                .discard_err()
                         {
                             self.process_immediate(bb, discr_target, discr_value, state);
                         }
@@ -567,7 +559,7 @@ 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 Some(enum_layout) = self.ecx.layout_of(enum_ty).discard_interp_err() else {
+                let Ok(enum_layout) = self.ecx.layout_of(enum_ty) else {
                     return;
                 };
                 let writes_discriminant = match enum_layout.variants {
@@ -582,10 +574,8 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
                     } => *variant_index != untagged_variant,
                 };
                 if writes_discriminant {
-                    let Some(discr) = self
-                        .ecx
-                        .discriminant_for_variant(enum_ty, *variant_index)
-                        .discard_interp_err()
+                    let Some(discr) =
+                        self.ecx.discriminant_for_variant(enum_ty, *variant_index).discard_err()
                     else {
                         return;
                     };
@@ -662,7 +652,7 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
 
         let Some(discr) = discr.place() else { return };
         let discr_ty = discr.ty(self.body, self.tcx).ty;
-        let Some(discr_layout) = self.ecx.layout_of(discr_ty).discard_interp_err() else {
+        let Ok(discr_layout) = self.ecx.layout_of(discr_ty) else {
             return;
         };
         let Some(conditions) = state.try_get(discr.as_ref(), &self.map) else { return };
diff --git a/compiler/rustc_mir_transform/src/known_panics_lint.rs b/compiler/rustc_mir_transform/src/known_panics_lint.rs
index b165ea53440..ccc029b1e28 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::{
-    DiscardInterpError, ImmTy, InterpCx, InterpResult, Projectable, Scalar, format_interp_error,
+    ImmTy, InterpCx, InterpResult, Projectable, Scalar, format_interp_error, interp_ok,
 };
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::HirId;
@@ -101,8 +101,7 @@ 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).discard_interp_err()?.try_into().ok()?;
+                    let idx = prop.ecx.read_target_usize(idx).discard_err()?.try_into().ok()?;
                     if idx <= FieldIdx::MAX_AS_U32 {
                         fields.get(FieldIdx::from_u32(idx)).unwrap_or(&Value::Uninit)
                     } else {
@@ -232,22 +231,20 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
     where
         F: FnOnce(&mut Self) -> InterpResult<'tcx, T>,
     {
-        match f(self) {
-            Ok(val) => Some(val),
-            Err(error) => {
-                trace!("InterpCx operation failed: {:?}", error);
+        f(self)
+            .map_err(|err| {
+                trace!("InterpCx operation failed: {:?}", err);
                 // Some errors shouldn't come up because creating them causes
                 // an allocation, which we should avoid. When that happens,
                 // dedicated error variants should be introduced instead.
                 assert!(
-                    !error.kind().formatted_string(),
+                    !err.kind().formatted_string(),
                     "known panics lint encountered formatting error: {}",
-                    format_interp_error(self.ecx.tcx.dcx(), error),
+                    format_interp_error(self.ecx.tcx.dcx(), err),
                 );
-                error.discard_interp_err();
-                None
-            }
-        }
+                err
+            })
+            .discard_err()
     }
 
     /// Returns the value, if any, of evaluating `c`.
@@ -317,7 +314,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                     .ecx
                     .binary_op(BinOp::SubWithOverflow, &ImmTy::from_int(0, arg.layout), &arg)?
                     .to_scalar_pair();
-                Ok((arg, overflow.to_bool()?))
+                interp_ok((arg, overflow.to_bool()?))
             })?;
             if overflow {
                 self.report_assert_as_lint(
@@ -349,9 +346,9 @@ 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).discard_interp_err()?.size;
+            let left_size = self.ecx.layout_of(left_ty).ok()?.size;
             let right_size = r.layout.size;
-            let r_bits = r.to_scalar().to_bits(right_size).discard_interp_err();
+            let r_bits = r.to_scalar().to_bits(right_size).discard_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(
@@ -498,7 +495,7 @@ 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).discard_interp_err())
+                    .and_then(|op| self.ecx.read_immediate(&op).discard_err())
                     .map_or(DbgVal::Underscore, |op| DbgVal::Val(op.to_const_int()))
             };
             let msg = match msg {
@@ -542,7 +539,7 @@ 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).discard_interp_err()?;
+        let layout = self.ecx.layout_of(dest.ty(self.body, self.tcx).ty).ok()?;
         trace!(?layout);
 
         let val: Value<'_> = match *rvalue {
@@ -604,7 +601,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
 
             Len(place) => {
                 let len = match self.get_const(place)? {
-                    Value::Immediate(src) => src.len(&self.ecx).discard_interp_err()?,
+                    Value::Immediate(src) => src.len(&self.ecx).discard_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)?,
@@ -617,7 +614,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             Ref(..) | RawPtr(..) => return None,
 
             NullaryOp(ref null_op, ty) => {
-                let op_layout = self.use_ecx(|this| this.ecx.layout_of(ty))?;
+                let op_layout = self.ecx.layout_of(ty).ok()?;
                 let val = match null_op {
                     NullOp::SizeOf => op_layout.size.bytes(),
                     NullOp::AlignOf => op_layout.align.abi.bytes(),
@@ -635,21 +632,21 @@ 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).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()?;
+                    let value = self.ecx.read_immediate(&value).discard_err()?;
+                    let to = self.ecx.layout_of(to).ok()?;
+                    let res = self.ecx.int_to_int_or_float(&value, to).discard_err()?;
                     res.into()
                 }
                 CastKind::FloatToFloat | CastKind::FloatToInt => {
                     let value = self.eval_operand(value)?;
-                    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()?;
+                    let value = self.ecx.read_immediate(&value).discard_err()?;
+                    let to = self.ecx.layout_of(to).ok()?;
+                    let res = self.ecx.float_to_float_or_int(&value, to).discard_err()?;
                     res.into()
                 }
                 CastKind::Transmute => {
                     let value = self.eval_operand(value)?;
-                    let to = self.ecx.layout_of(to).discard_interp_err()?;
+                    let to = self.ecx.layout_of(to).ok()?;
                     // `offset` for immediates only supports scalar/scalar-pair ABIs,
                     // so bail out if the target is not one.
                     match (value.layout.abi, to.abi) {
@@ -658,7 +655,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                         _ => return None,
                     }
 
-                    value.offset(Size::ZERO, to, &self.ecx).discard_interp_err()?.into()
+                    value.offset(Size::ZERO, to, &self.ecx).discard_err()?.into()
                 }
                 _ => return None,
             },
@@ -783,8 +780,7 @@ 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 Some(constant) =
-                        value_const.to_bits(value_const.size()).discard_interp_err()
+                    && let Some(constant) = value_const.to_bits(value_const.size()).discard_err()
                 {
                     // We managed to evaluate the discriminant, so we know we only need to visit
                     // one target.