Upgrade Rust toolchain to 2025-12-31

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

@@ -1321,7 +1321,7 @@ impl GotocCtx<'_, '_> {
     ) -> Expr {
         debug!(cast=?coercion, op=?operand, ?loc, "codegen_pointer_cast");
         match coercion {
-            PointerCoercion::ReifyFnPointer => match self.operand_ty_stable(operand).kind() {
+            PointerCoercion::ReifyFnPointer(_) => match self.operand_ty_stable(operand).kind() {
                 TyKind::RigidTy(RigidTy::FnDef(def, args)) => {
                     let instance = Instance::resolve(def, &args).unwrap();
                     // We need to handle this case in a special way because `codegen_operand_stable` compiles FnDefs to dummy structs.

kani-compiler/src/kani_middle/reachability.rs

@@ -349,7 +349,7 @@ impl MirVisitor for MonoItemsFnCollector<'_, '_> {
                 }
             }
             Rvalue::Cast(
-                CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer),
+                CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer(_)),
                 ref operand,
                 _,
             ) => {

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

@@ -101,8 +101,8 @@ impl RustcInternalMir for PointerCoercion {
 
     fn internal_mir<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
-            PointerCoercion::ReifyFnPointer => {
-                rustc_middle::ty::adjustment::PointerCoercion::ReifyFnPointer
+            PointerCoercion::ReifyFnPointer(safety) => {
+                rustc_middle::ty::adjustment::PointerCoercion::ReifyFnPointer(internal(tcx, safety))
             }
             PointerCoercion::UnsafeFnPointer => {
                 rustc_middle::ty::adjustment::PointerCoercion::UnsafeFnPointer

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2025-12-05"
+channel = "nightly-2025-12-16"
 components = ["llvm-tools", "rustc-dev", "rust-src", "rustfmt"]