diff --git a/rust-version b/rust-version
index cada8fabde57..cb81868b2aec 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-4f49627c6fe2a32d1fed6310466bb0e1c535c0c0
+ddabe0775c5f5b551d5eb54e3c4366fb8bec0c92
diff --git a/src/machine.rs b/src/machine.rs
index 7cde8a8df681..3ca07db921a9 100644
--- a/src/machine.rs
+++ b/src/machine.rs
@@ -7,7 +7,6 @@ use std::fmt;
 use std::num::NonZeroU64;
 use std::time::Instant;
 
-use log::trace;
 use rand::rngs::StdRng;
 use rand::SeedableRng;
 
@@ -503,35 +502,6 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         ecx.binary_ptr_op(bin_op, left, right)
     }
 
-    fn box_alloc(
-        ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        dest: &PlaceTy<'tcx, Tag>,
-    ) -> InterpResult<'tcx> {
-        trace!("box_alloc for {:?}", dest.layout.ty);
-        let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
-        // First argument: `size`.
-        // (`0` is allowed here -- this is expected to be handled by the lang item).
-        let size = Scalar::from_machine_usize(layout.size.bytes(), ecx);
-
-        // Second argument: `align`.
-        let align = Scalar::from_machine_usize(layout.align.abi.bytes(), ecx);
-
-        // Call the `exchange_malloc` lang item.
-        let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
-        let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
-        ecx.call_function(
-            malloc,
-            Abi::Rust,
-            &[size.into(), align.into()],
-            Some(dest),
-            // Don't do anything when we are done. The `statement()` function will increment
-            // the old stack frame's stmt counter to the next statement, which means that when
-            // `exchange_malloc` returns, we go on evaluating exactly where we want to be.
-            StackPopCleanup::None { cleanup: true },
-        )?;
-        Ok(())
-    }
-
     fn thread_local_static_base_pointer(
         ecx: &mut InterpCx<'mir, 'tcx, Self>,
         def_id: DefId,