Upgrade Rust toolchain to 2025-11-19 (#4482)

Relevant upstream PR:
- rust-lang/rust#148151 (Replace OffsetOf by an
actual sum of calls to intrinsic.)

Resolves: #4481

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 and MIT licenses.

Author: tautschnig

kani-compiler/src/codegen_cprover_gotoc/codegen/rvalue.rs

@@ -19,7 +19,7 @@ use cbmc::goto_program::{
 use cbmc::{InternString, InternedString, btree_string_map};
 use num::bigint::BigInt;
 use rustc_abi::{FieldsShape, TagEncoding, Variants};
-use rustc_middle::ty::{TyCtxt, TypingEnv, VtblEntry};
+use rustc_middle::ty::{TyCtxt, VtblEntry};
 use rustc_public::abi::{Primitive, Scalar, ValueAbi};
 use rustc_public::mir::mono::Instance;
 use rustc_public::mir::{
@@ -824,27 +824,7 @@ impl GotocCtx<'_, '_> {
             Rvalue::CheckedBinaryOp(op, e1, e2) => {
                 self.codegen_rvalue_checked_binary_op(op, e1, e2, res_ty)
             }
-            Rvalue::NullaryOp(k, t) => {
-                let layout = self.layout_of_stable(*t);
-                match k {
-                    NullOp::OffsetOf(fields) => Expr::int_constant(
-                        self.tcx
-                            .offset_of_subfield(
-                                TypingEnv::fully_monomorphized(),
-                                layout,
-                                fields.iter().map(|(var_idx, field_idx)| {
-                                    (
-                                        rustc_internal::internal(self.tcx, var_idx),
-                                        (*field_idx).into(),
-                                    )
-                                }),
-                            )
-                            .bytes(),
-                        Type::size_t(),
-                    ),
-                    NullOp::RuntimeChecks(_) => Expr::c_false(),
-                }
-            }
+            Rvalue::NullaryOp(NullOp::RuntimeChecks(_)) => Expr::c_false(),
             Rvalue::ShallowInitBox(operand, content_ty) => {
                 // The behaviour of ShallowInitBox is simply transmuting *mut u8 to Box<T>.
                 // See https://github.com/rust-lang/compiler-team/issues/460 for more details.

kani-compiler/src/kani_middle/analysis.rs

@@ -168,7 +168,7 @@ impl From<&Rvalue> for Key {
             Rvalue::Cast(_, _, _) => Key("Cast"),
             Rvalue::BinaryOp(..) => Key("BinaryOp"),
             Rvalue::CheckedBinaryOp(..) => Key("CheckedBinaryOp"),
-            Rvalue::NullaryOp(_, _) => Key("NullaryOp"),
+            Rvalue::NullaryOp(_) => Key("NullaryOp"),
             Rvalue::UnaryOp(_, _) => Key("UnaryOp"),
             Rvalue::Discriminant(_) => Key("Discriminant"),
             Rvalue::Aggregate(_, _) => Key("Aggregate"),

kani-compiler/src/kani_middle/transform/check_values.rs

@@ -699,7 +699,7 @@ impl MirVisitor for CheckValueVisitor<'_, '_> {
             | Rvalue::Ref(_, _, _)
             | Rvalue::Repeat(_, _)
             | Rvalue::ThreadLocalRef(_)
-            | Rvalue::NullaryOp(_, _)
+            | Rvalue::NullaryOp(_)
             | Rvalue::UnaryOp(_, _)
             | Rvalue::Use(_) => {}
         }

kani-compiler/src/kani_middle/transform/internal_mir.rs

@@ -191,24 +191,10 @@ impl RustcInternalMir for BorrowKind {
 }
 
 impl RustcInternalMir for NullOp {
-    type T<'tcx> = rustc_middle::mir::NullOp<'tcx>;
+    type T<'tcx> = rustc_middle::mir::NullOp;
 
-    fn internal_mir<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
+    fn internal_mir<'tcx>(&self, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
-            NullOp::OffsetOf(offsets) => rustc_middle::mir::NullOp::OffsetOf(
-                tcx.mk_offset_of(
-                    offsets
-                        .iter()
-                        .map(|(variant_idx, field_idx)| {
-                            (
-                                internal(tcx, variant_idx),
-                                rustc_abi::FieldIdx::from_usize(*field_idx),
-                            )
-                        })
-                        .collect::<Vec<_>>()
-                        .as_slice(),
-                ),
-            ),
             NullOp::RuntimeChecks(RuntimeChecks::UbChecks) => {
                 rustc_middle::mir::NullOp::RuntimeChecks(rustc_middle::mir::RuntimeChecks::UbChecks)
             }
@@ -278,8 +264,8 @@ impl RustcInternalMir for Rvalue {
             Rvalue::ThreadLocalRef(crate_item) => {
                 rustc_middle::mir::Rvalue::ThreadLocalRef(internal(tcx, crate_item.0))
             }
-            Rvalue::NullaryOp(null_op, ty) => {
-                rustc_middle::mir::Rvalue::NullaryOp(null_op.internal_mir(tcx), internal(tcx, ty))
+            Rvalue::NullaryOp(null_op) => {
+                rustc_middle::mir::Rvalue::NullaryOp(null_op.internal_mir(tcx))
             }
             Rvalue::UnaryOp(un_op, operand) => {
                 rustc_middle::mir::Rvalue::UnaryOp(internal(tcx, un_op), operand.internal_mir(tcx))

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2025-11-18"
+channel = "nightly-2025-11-19"
 components = ["llvm-tools", "rustc-dev", "rust-src", "rustfmt"]