diff --git a/compiler/rustc_codegen_cranelift/src/constant.rs b/compiler/rustc_codegen_cranelift/src/constant.rs
index cf68a3857c58..65f7ee6999a7 100644
--- a/compiler/rustc_codegen_cranelift/src/constant.rs
+++ b/compiler/rustc_codegen_cranelift/src/constant.rs
@@ -126,7 +126,8 @@ pub(crate) fn codegen_const_value<'tcx>(
                 }
             }
             Scalar::Ptr(ptr, _size) => {
-                let (alloc_id, offset) = ptr.into_parts(); // we know the `offset` is relative
+                let (prov, offset) = ptr.into_parts(); // we know the `offset` is relative
+                let alloc_id = prov.alloc_id();
                 let base_addr = match fx.tcx.global_alloc(alloc_id) {
                     GlobalAlloc::Memory(alloc) => {
                         let data_id = data_id_for_alloc_id(
@@ -374,7 +375,8 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut Constant
         let bytes = alloc.inspect_with_uninit_and_ptr_outside_interpreter(0..alloc.len()).to_vec();
         data.define(bytes.into_boxed_slice());
 
-        for &(offset, alloc_id) in alloc.provenance().ptrs().iter() {
+        for &(offset, prov) in alloc.provenance().ptrs().iter() {
+            let alloc_id = prov.alloc_id();
             let addend = {
                 let endianness = tcx.data_layout.endian;
                 let offset = offset.bytes() as usize;
diff --git a/compiler/rustc_codegen_gcc/src/common.rs b/compiler/rustc_codegen_gcc/src/common.rs
index 93fe27e547ae..b7ddc410315c 100644
--- a/compiler/rustc_codegen_gcc/src/common.rs
+++ b/compiler/rustc_codegen_gcc/src/common.rs
@@ -199,7 +199,8 @@ fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, ty: Type<'gcc>) ->
                 }
             }
             Scalar::Ptr(ptr, _size) => {
-                let (alloc_id, offset) = ptr.into_parts();
+                let (prov, offset) = ptr.into_parts(); // we know the `offset` is relative
+                let alloc_id = prov.alloc_id();
                 let base_addr =
                     match self.tcx.global_alloc(alloc_id) {
                         GlobalAlloc::Memory(alloc) => {
diff --git a/compiler/rustc_codegen_gcc/src/consts.rs b/compiler/rustc_codegen_gcc/src/consts.rs
index d8a1fd315c0a..f06416b9bb5f 100644
--- a/compiler/rustc_codegen_gcc/src/consts.rs
+++ b/compiler/rustc_codegen_gcc/src/consts.rs
@@ -285,7 +285,8 @@ pub fn const_alloc_to_gcc<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, alloc: ConstAl
     let pointer_size = dl.pointer_size.bytes() as usize;
 
     let mut next_offset = 0;
-    for &(offset, alloc_id) in alloc.provenance().ptrs().iter() {
+    for &(offset, prov) in alloc.provenance().ptrs().iter() {
+        let alloc_id = prov.alloc_id();
         let offset = offset.bytes();
         assert_eq!(offset as usize as u64, offset);
         let offset = offset as usize;
@@ -313,7 +314,7 @@ pub fn const_alloc_to_gcc<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, alloc: ConstAl
 
         llvals.push(cx.scalar_to_backend(
             InterpScalar::from_pointer(
-                interpret::Pointer::new(alloc_id, Size::from_bytes(ptr_offset)),
+                interpret::Pointer::new(prov, Size::from_bytes(ptr_offset)),
                 &cx.tcx,
             ),
             abi::Scalar::Initialized { value: Primitive::Pointer(address_space), valid_range: WrappingRange::full(dl.pointer_size) },
diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs
index d1b643f49677..8173e41aff45 100644
--- a/compiler/rustc_codegen_llvm/src/common.rs
+++ b/compiler/rustc_codegen_llvm/src/common.rs
@@ -246,8 +246,8 @@ fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, llty: &'ll Type) ->
                 }
             }
             Scalar::Ptr(ptr, _size) => {
-                let (alloc_id, offset) = ptr.into_parts();
-                let (base_addr, base_addr_space) = match self.tcx.global_alloc(alloc_id) {
+                let (prov, offset) = ptr.into_parts();
+                let (base_addr, base_addr_space) = match self.tcx.global_alloc(prov.alloc_id()) {
                     GlobalAlloc::Memory(alloc) => {
                         let init = const_alloc_to_llvm(self, alloc);
                         let alloc = alloc.inner();
diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs
index b6bc5395bf6b..21ff267ca674 100644
--- a/compiler/rustc_codegen_llvm/src/consts.rs
+++ b/compiler/rustc_codegen_llvm/src/consts.rs
@@ -72,7 +72,7 @@ fn append_chunks_of_init_and_uninit_bytes<'ll, 'a, 'b>(
     }
 
     let mut next_offset = 0;
-    for &(offset, alloc_id) in alloc.provenance().ptrs().iter() {
+    for &(offset, prov) in alloc.provenance().ptrs().iter() {
         let offset = offset.bytes();
         assert_eq!(offset as usize as u64, offset);
         let offset = offset as usize;
@@ -92,13 +92,10 @@ fn append_chunks_of_init_and_uninit_bytes<'ll, 'a, 'b>(
         .expect("const_alloc_to_llvm: could not read relocation pointer")
             as u64;
 
-        let address_space = cx.tcx.global_alloc(alloc_id).address_space(cx);
+        let address_space = cx.tcx.global_alloc(prov.alloc_id()).address_space(cx);
 
         llvals.push(cx.scalar_to_backend(
-            InterpScalar::from_pointer(
-                Pointer::new(alloc_id, Size::from_bytes(ptr_offset)),
-                &cx.tcx,
-            ),
+            InterpScalar::from_pointer(Pointer::new(prov, Size::from_bytes(ptr_offset)), &cx.tcx),
             Scalar::Initialized {
                 value: Primitive::Pointer(address_space),
                 valid_range: WrappingRange::full(dl.pointer_size),
diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs
index 0ab2b7ecd9c8..79205bf9e6a5 100644
--- a/compiler/rustc_codegen_ssa/src/mir/operand.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs
@@ -105,7 +105,7 @@ pub fn from_const<Bx: BuilderMethods<'a, 'tcx, Value = V>>(
                     bug!("from_const: invalid ScalarPair layout: {:#?}", layout);
                 };
                 let a = Scalar::from_pointer(
-                    Pointer::new(bx.tcx().reserve_and_set_memory_alloc(data), Size::ZERO),
+                    Pointer::new(bx.tcx().reserve_and_set_memory_alloc(data).into(), Size::ZERO),
                     &bx.tcx(),
                 );
                 let a_llval = bx.scalar_to_backend(
diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
index edfece07d190..9ca5ce40e768 100644
--- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
+++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
@@ -155,8 +155,8 @@ pub(super) fn op_to_const<'tcx>(
     match immediate {
         Left(ref mplace) => {
             // We know `offset` is relative to the allocation, so we can use `into_parts`.
-            let (alloc_id, offset) = mplace.ptr().into_parts();
-            let alloc_id = alloc_id.expect("cannot have `fake` place fot non-ZST type");
+            let (prov, offset) = mplace.ptr().into_parts();
+            let alloc_id = prov.expect("cannot have `fake` place for non-ZST type").alloc_id();
             ConstValue::Indirect { alloc_id, offset }
         }
         // see comment on `let force_as_immediate` above
@@ -178,8 +178,8 @@ pub(super) fn op_to_const<'tcx>(
                 );
                 let msg = "`op_to_const` on an immediate scalar pair must only be used on slice references to the beginning of an actual allocation";
                 // We know `offset` is relative to the allocation, so we can use `into_parts`.
-                let (alloc_id, offset) = a.to_pointer(ecx).expect(msg).into_parts();
-                let alloc_id = alloc_id.expect(msg);
+                let (prov, offset) = a.to_pointer(ecx).expect(msg).into_parts();
+                let alloc_id = prov.expect(msg).alloc_id();
                 let data = ecx.tcx.global_alloc(alloc_id).unwrap_memory();
                 assert!(offset == abi::Size::ZERO, "{}", msg);
                 let meta = b.to_target_usize(ecx).expect(msg);
@@ -353,7 +353,7 @@ pub fn eval_in_interpreter<'mir, 'tcx>(
             let validation =
                 const_validate_mplace(&ecx, &mplace, is_static, cid.promoted.is_some());
 
-            let alloc_id = mplace.ptr().provenance.unwrap();
+            let alloc_id = mplace.ptr().provenance.unwrap().alloc_id();
 
             // Validation failed, report an error.
             if let Err(error) = validation {
diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
index 2d8ca67c3a51..015e19a0fff1 100644
--- a/compiler/rustc_const_eval/src/const_eval/machine.rs
+++ b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -49,7 +49,7 @@ pub struct CompileTimeInterpreter<'mir, 'tcx> {
     pub(super) num_evaluated_steps: usize,
 
     /// The virtual call stack.
-    pub(super) stack: Vec<Frame<'mir, 'tcx, AllocId, ()>>,
+    pub(super) stack: Vec<Frame<'mir, 'tcx>>,
 
     /// We need to make sure consts never point to anything mutable, even recursively. That is
     /// relied on for pattern matching on consts with references.
@@ -638,10 +638,7 @@ fn increment_const_eval_counter(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpR
     }
 
     #[inline(always)]
-    fn expose_ptr(
-        _ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        _ptr: Pointer<AllocId>,
-    ) -> InterpResult<'tcx> {
+    fn expose_ptr(_ecx: &mut InterpCx<'mir, 'tcx, Self>, _ptr: Pointer) -> InterpResult<'tcx> {
         // This is only reachable with -Zunleash-the-miri-inside-of-you.
         throw_unsup_format!("exposing pointers is not possible at compile-time")
     }
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index c0a20e51482f..f8ed9302b866 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -7,7 +7,9 @@
 use rustc_hir::{self as hir, def_id::DefId, definitions::DefPathData};
 use rustc_index::IndexVec;
 use rustc_middle::mir;
-use rustc_middle::mir::interpret::{ErrorHandled, InvalidMetaKind, ReportedErrorInfo};
+use rustc_middle::mir::interpret::{
+    CtfeProvenance, ErrorHandled, InvalidMetaKind, ReportedErrorInfo,
+};
 use rustc_middle::query::TyCtxtAt;
 use rustc_middle::ty::layout::{
     self, FnAbiError, FnAbiOfHelpers, FnAbiRequest, LayoutError, LayoutOf, LayoutOfHelpers,
@@ -20,9 +22,9 @@
 use rustc_target::abi::{call::FnAbi, Align, HasDataLayout, Size, TargetDataLayout};
 
 use super::{
-    AllocId, GlobalId, Immediate, InterpErrorInfo, InterpResult, MPlaceTy, Machine, MemPlace,
-    MemPlaceMeta, Memory, MemoryKind, OpTy, Operand, Place, PlaceTy, Pointer, PointerArithmetic,
-    Projectable, Provenance, Scalar, StackPopJump,
+    GlobalId, Immediate, InterpErrorInfo, InterpResult, MPlaceTy, Machine, MemPlace, MemPlaceMeta,
+    Memory, MemoryKind, OpTy, Operand, Place, PlaceTy, Pointer, PointerArithmetic, Projectable,
+    Provenance, Scalar, StackPopJump,
 };
 use crate::errors;
 use crate::util;
@@ -84,7 +86,7 @@ fn drop(&mut self) {
 }
 
 /// A stack frame.
-pub struct Frame<'mir, 'tcx, Prov: Provenance = AllocId, Extra = ()> {
+pub struct Frame<'mir, 'tcx, Prov: Provenance = CtfeProvenance, Extra = ()> {
     ////////////////////////////////////////////////////////////////////////////////
     // Function and callsite information
     ////////////////////////////////////////////////////////////////////////////////
@@ -156,7 +158,7 @@ pub enum StackPopCleanup {
 
 /// State of a local variable including a memoized layout
 #[derive(Clone)]
-pub struct LocalState<'tcx, Prov: Provenance = AllocId> {
+pub struct LocalState<'tcx, Prov: Provenance = CtfeProvenance> {
     value: LocalValue<Prov>,
     /// Don't modify if `Some`, this is only used to prevent computing the layout twice.
     /// Avoids computing the layout of locals that are never actually initialized.
@@ -177,7 +179,7 @@ fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 /// This does not store the type of the local; the type is given by `body.local_decls` and can never
 /// change, so by not storing here we avoid having to maintain that as an invariant.
 #[derive(Copy, Clone, Debug)] // Miri debug-prints these
-pub(super) enum LocalValue<Prov: Provenance = AllocId> {
+pub(super) enum LocalValue<Prov: Provenance = CtfeProvenance> {
     /// This local is not currently alive, and cannot be used at all.
     Dead,
     /// A normal, live local.
diff --git a/compiler/rustc_const_eval/src/interpret/intern.rs b/compiler/rustc_const_eval/src/interpret/intern.rs
index 881df9b04ab2..7931789e4363 100644
--- a/compiler/rustc_const_eval/src/interpret/intern.rs
+++ b/compiler/rustc_const_eval/src/interpret/intern.rs
@@ -18,7 +18,7 @@
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
-use rustc_middle::mir::interpret::InterpResult;
+use rustc_middle::mir::interpret::{CtfeProvenance, InterpResult};
 use rustc_middle::ty::{self, layout::TyAndLayout, Ty};
 
 use rustc_ast::Mutability;
@@ -34,7 +34,7 @@ pub trait CompileTimeMachine<'mir, 'tcx: 'mir, T> = Machine<
         'mir,
         'tcx,
         MemoryKind = T,
-        Provenance = AllocId,
+        Provenance = CtfeProvenance,
         ExtraFnVal = !,
         FrameExtra = (),
         AllocExtra = (),
@@ -135,7 +135,7 @@ fn intern_shallow<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx, const_eval:
         alloc.mutability = Mutability::Not;
     };
     // link the alloc id to the actual allocation
-    leftover_allocations.extend(alloc.provenance().ptrs().iter().map(|&(_, alloc_id)| alloc_id));
+    leftover_allocations.extend(alloc.provenance().ptrs().iter().map(|&(_, prov)| prov.alloc_id()));
     let alloc = tcx.mk_const_alloc(alloc);
     tcx.set_alloc_id_memory(alloc_id, alloc);
     None
@@ -178,10 +178,10 @@ fn visit_value(&mut self, mplace: &MPlaceTy<'tcx>) -> InterpResult<'tcx> {
                 tcx.struct_tail_erasing_lifetimes(referenced_ty, self.ecx.param_env).kind()
             {
                 let ptr = mplace.meta().unwrap_meta().to_pointer(&tcx)?;
-                if let Some(alloc_id) = ptr.provenance {
+                if let Some(prov) = ptr.provenance {
                     // Explicitly choose const mode here, since vtables are immutable, even
                     // if the reference of the fat pointer is mutable.
-                    self.intern_shallow(alloc_id, InternMode::Const, None);
+                    self.intern_shallow(prov.alloc_id(), InternMode::Const, None);
                 } else {
                     // Validation will error (with a better message) on an invalid vtable pointer.
                     // Let validation show the error message, but make sure it *does* error.
@@ -191,7 +191,7 @@ fn visit_value(&mut self, mplace: &MPlaceTy<'tcx>) -> InterpResult<'tcx> {
             }
             // Check if we have encountered this pointer+layout combination before.
             // Only recurse for allocation-backed pointers.
-            if let Some(alloc_id) = mplace.ptr().provenance {
+            if let Some(prov) = mplace.ptr().provenance {
                 // Compute the mode with which we intern this. Our goal here is to make as many
                 // statics as we can immutable so they can be placed in read-only memory by LLVM.
                 let ref_mode = match self.mode {
@@ -234,7 +234,7 @@ fn visit_value(&mut self, mplace: &MPlaceTy<'tcx>) -> InterpResult<'tcx> {
                         InternMode::Const
                     }
                 };
-                match self.intern_shallow(alloc_id, ref_mode, Some(referenced_ty)) {
+                match self.intern_shallow(prov.alloc_id(), ref_mode, Some(referenced_ty)) {
                     // No need to recurse, these are interned already and statics may have
                     // cycles, so we don't want to recurse there
                     Some(IsStaticOrFn) => {}
@@ -353,7 +353,7 @@ pub fn intern_const_alloc_recursive<
         leftover_allocations,
         // The outermost allocation must exist, because we allocated it with
         // `Memory::allocate`.
-        ret.ptr().provenance.unwrap(),
+        ret.ptr().provenance.unwrap().alloc_id(),
         base_intern_mode,
         Some(ret.layout.ty),
     );
@@ -431,7 +431,8 @@ pub fn intern_const_alloc_recursive<
             }
             let alloc = tcx.mk_const_alloc(alloc);
             tcx.set_alloc_id_memory(alloc_id, alloc);
-            for &(_, alloc_id) in alloc.inner().provenance().ptrs().iter() {
+            for &(_, prov) in alloc.inner().provenance().ptrs().iter() {
+                let alloc_id = prov.alloc_id();
                 if leftover_allocations.insert(alloc_id) {
                     todo.push(alloc_id);
                 }
@@ -503,10 +504,11 @@ pub fn intern_with_temp_alloc(
         // `allocate` picks a fresh AllocId that we will associate with its data below.
         let dest = self.allocate(layout, MemoryKind::Stack)?;
         f(self, &dest.clone().into())?;
-        let mut alloc = self.memory.alloc_map.remove(&dest.ptr().provenance.unwrap()).unwrap().1;
+        let mut alloc =
+            self.memory.alloc_map.remove(&dest.ptr().provenance.unwrap().alloc_id()).unwrap().1;
         alloc.mutability = Mutability::Not;
         let alloc = self.tcx.mk_const_alloc(alloc);
-        let alloc_id = dest.ptr().provenance.unwrap(); // this was just allocated, it must have provenance
+        let alloc_id = dest.ptr().provenance.unwrap().alloc_id(); // this was just allocated, it must have provenance
         self.tcx.set_alloc_id_memory(alloc_id, alloc);
         Ok(alloc_id)
     }
diff --git a/compiler/rustc_const_eval/src/interpret/machine.rs b/compiler/rustc_const_eval/src/interpret/machine.rs
index 221ff2b60e9e..fe603e5c1fe3 100644
--- a/compiler/rustc_const_eval/src/interpret/machine.rs
+++ b/compiler/rustc_const_eval/src/interpret/machine.rs
@@ -16,8 +16,9 @@
 use rustc_target::spec::abi::Abi as CallAbi;
 
 use super::{
-    AllocBytes, AllocId, AllocKind, AllocRange, Allocation, ConstAllocation, FnArg, Frame, ImmTy,
-    InterpCx, InterpResult, MPlaceTy, MemoryKind, Misalignment, OpTy, PlaceTy, Pointer, Provenance,
+    AllocBytes, AllocId, AllocKind, AllocRange, Allocation, ConstAllocation, CtfeProvenance, FnArg,
+    Frame, ImmTy, InterpCx, InterpResult, MPlaceTy, MemoryKind, Misalignment, OpTy, PlaceTy,
+    Pointer, Provenance,
 };
 
 /// Data returned by Machine::stack_pop,
@@ -513,8 +514,8 @@ fn after_local_allocated(
 /// A lot of the flexibility above is just needed for `Miri`, but all "compile-time" machines
 /// (CTFE and ConstProp) use the same instance. Here, we share that code.
 pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
-    type Provenance = AllocId;
-    type ProvenanceExtra = ();
+    type Provenance = CtfeProvenance;
+    type ProvenanceExtra = (); // FIXME extract the "immutable" bool?
 
     type ExtraFnVal = !;
 
@@ -567,14 +568,14 @@ fn extern_static_base_pointer(
         def_id: DefId,
     ) -> InterpResult<$tcx, Pointer> {
         // Use the `AllocId` associated with the `DefId`. Any actual *access* will fail.
-        Ok(Pointer::new(ecx.tcx.reserve_and_set_static_alloc(def_id), Size::ZERO))
+        Ok(Pointer::new(ecx.tcx.reserve_and_set_static_alloc(def_id).into(), Size::ZERO))
     }
 
     #[inline(always)]
     fn adjust_alloc_base_pointer(
         _ecx: &InterpCx<$mir, $tcx, Self>,
-        ptr: Pointer<AllocId>,
-    ) -> InterpResult<$tcx, Pointer<AllocId>> {
+        ptr: Pointer<CtfeProvenance>,
+    ) -> InterpResult<$tcx, Pointer<CtfeProvenance>> {
         Ok(ptr)
     }
 
@@ -582,7 +583,7 @@ fn adjust_alloc_base_pointer(
     fn ptr_from_addr_cast(
         _ecx: &InterpCx<$mir, $tcx, Self>,
         addr: u64,
-    ) -> InterpResult<$tcx, Pointer<Option<AllocId>>> {
+    ) -> InterpResult<$tcx, Pointer<Option<CtfeProvenance>>> {
         // Allow these casts, but make the pointer not dereferenceable.
         // (I.e., they behave like transmutation.)
         // This is correct because no pointers can ever be exposed in compile-time evaluation.
@@ -592,10 +593,10 @@ fn ptr_from_addr_cast(
     #[inline(always)]
     fn ptr_get_alloc(
         _ecx: &InterpCx<$mir, $tcx, Self>,
-        ptr: Pointer<AllocId>,
+        ptr: Pointer<CtfeProvenance>,
     ) -> Option<(AllocId, Size, Self::ProvenanceExtra)> {
         // We know `offset` is relative to the allocation, so we can use `into_parts`.
-        let (alloc_id, offset) = ptr.into_parts();
-        Some((alloc_id, offset, ()))
+        let (prov, offset) = ptr.into_parts();
+        Some((prov.alloc_id(), offset, ()))
     }
 }
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index f865c0cc5fa6..13530e9d9c49 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -22,8 +22,8 @@
 
 use super::{
     alloc_range, AllocBytes, AllocId, AllocMap, AllocRange, Allocation, CheckAlignMsg,
-    CheckInAllocMsg, GlobalAlloc, InterpCx, InterpResult, Machine, MayLeak, Misalignment, Pointer,
-    PointerArithmetic, Provenance, Scalar,
+    CheckInAllocMsg, CtfeProvenance, GlobalAlloc, InterpCx, InterpResult, Machine, MayLeak,
+    Misalignment, Pointer, PointerArithmetic, Provenance, Scalar,
 };
 
 #[derive(Debug, PartialEq, Copy, Clone)]
@@ -159,9 +159,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     #[inline]
     pub fn global_base_pointer(
         &self,
-        ptr: Pointer<AllocId>,
+        ptr: Pointer<CtfeProvenance>,
     ) -> InterpResult<'tcx, Pointer<M::Provenance>> {
-        let alloc_id = ptr.provenance;
+        let alloc_id = ptr.provenance.alloc_id();
         // We need to handle `extern static`.
         match self.tcx.try_get_global_alloc(alloc_id) {
             Some(GlobalAlloc::Static(def_id)) if self.tcx.is_thread_local_static(def_id) => {
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index 255dd1eba97f..66cf38c09a08 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -13,9 +13,9 @@
 use rustc_target::abi::{self, Abi, HasDataLayout, Size};
 
 use super::{
-    alloc_range, from_known_layout, mir_assign_valid_types, AllocId, Frame, InterpCx, InterpResult,
-    MPlaceTy, Machine, MemPlace, MemPlaceMeta, OffsetMode, PlaceTy, Pointer, Projectable,
-    Provenance, Scalar,
+    alloc_range, from_known_layout, mir_assign_valid_types, CtfeProvenance, Frame, InterpCx,
+    InterpResult, MPlaceTy, Machine, MemPlace, MemPlaceMeta, OffsetMode, PlaceTy, Pointer,
+    Projectable, Provenance, Scalar,
 };
 
 /// An `Immediate` represents a single immediate self-contained Rust value.
@@ -26,7 +26,7 @@
 /// In particular, thanks to `ScalarPair`, arithmetic operations and casts can be entirely
 /// defined on `Immediate`, and do not have to work with a `Place`.
 #[derive(Copy, Clone, Debug)]
-pub enum Immediate<Prov: Provenance = AllocId> {
+pub enum Immediate<Prov: Provenance = CtfeProvenance> {
     /// A single scalar value (must have *initialized* `Scalar` ABI).
     Scalar(Scalar<Prov>),
     /// A pair of two scalar value (must have `ScalarPair` ABI where both fields are
@@ -98,7 +98,7 @@ pub fn to_scalar_pair(self) -> (Scalar<Prov>, Scalar<Prov>) {
 // ScalarPair needs a type to interpret, so we often have an immediate and a type together
 // as input for binary and cast operations.
 #[derive(Clone)]
-pub struct ImmTy<'tcx, Prov: Provenance = AllocId> {
+pub struct ImmTy<'tcx, Prov: Provenance = CtfeProvenance> {
     imm: Immediate<Prov>,
     pub layout: TyAndLayout<'tcx>,
 }
@@ -334,13 +334,13 @@ fn to_op<'mir, M: Machine<'mir, 'tcx, Provenance = Prov>>(
 /// or still in memory. The latter is an optimization, to delay reading that chunk of
 /// memory and to avoid having to store arbitrary-sized data here.
 #[derive(Copy, Clone, Debug)]
-pub(super) enum Operand<Prov: Provenance = AllocId> {
+pub(super) enum Operand<Prov: Provenance = CtfeProvenance> {
     Immediate(Immediate<Prov>),
     Indirect(MemPlace<Prov>),
 }
 
 #[derive(Clone)]
-pub struct OpTy<'tcx, Prov: Provenance = AllocId> {
+pub struct OpTy<'tcx, Prov: Provenance = CtfeProvenance> {
     op: Operand<Prov>, // Keep this private; it helps enforce invariants.
     pub layout: TyAndLayout<'tcx>,
 }
@@ -750,17 +750,19 @@ pub(crate) fn const_val_to_op(
         let layout = from_known_layout(self.tcx, self.param_env, layout, || self.layout_of(ty))?;
         let imm = match val_val {
             mir::ConstValue::Indirect { alloc_id, offset } => {
-                // We rely on mutability being set correctly in that allocation to prevent writes
-                // where none should happen.
-                let ptr = self.global_base_pointer(Pointer::new(alloc_id, offset))?;
+                // This is const data, no mutation allowed.
+                let ptr = self.global_base_pointer(Pointer::new(
+                    CtfeProvenance::from(alloc_id).as_immutable(),
+                    offset,
+                ))?;
                 return Ok(self.ptr_to_mplace(ptr.into(), layout).into());
             }
             mir::ConstValue::Scalar(x) => adjust_scalar(x)?.into(),
             mir::ConstValue::ZeroSized => Immediate::Uninit,
             mir::ConstValue::Slice { data, meta } => {
-                // We rely on mutability being set correctly in `data` to prevent writes
-                // where none should happen.
-                let ptr = Pointer::new(self.tcx.reserve_and_set_memory_alloc(data), Size::ZERO);
+                // This is const data, no mutation allowed.
+                let alloc_id = self.tcx.reserve_and_set_memory_alloc(data);
+                let ptr = Pointer::new(CtfeProvenance::from(alloc_id).as_immutable(), Size::ZERO);
                 Immediate::new_slice(self.global_base_pointer(ptr)?.into(), meta, self)
             }
         };
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index 04f0cdb326e2..148228f07963 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -14,14 +14,14 @@
 use rustc_target::abi::{Abi, Align, HasDataLayout, Size};
 
 use super::{
-    alloc_range, mir_assign_valid_types, AllocId, AllocRef, AllocRefMut, CheckAlignMsg, ImmTy,
-    Immediate, InterpCx, InterpResult, Machine, MemoryKind, Misalignment, OffsetMode, OpTy,
+    alloc_range, mir_assign_valid_types, AllocRef, AllocRefMut, CheckAlignMsg, CtfeProvenance,
+    ImmTy, Immediate, InterpCx, InterpResult, Machine, MemoryKind, Misalignment, OffsetMode, OpTy,
     Operand, Pointer, PointerArithmetic, Projectable, Provenance, Readable, Scalar,
 };
 
 #[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
 /// Information required for the sound usage of a `MemPlace`.
-pub enum MemPlaceMeta<Prov: Provenance = AllocId> {
+pub enum MemPlaceMeta<Prov: Provenance = CtfeProvenance> {
     /// The unsized payload (e.g. length for slices or vtable pointer for trait objects).
     Meta(Scalar<Prov>),
     /// `Sized` types or unsized `extern type`
@@ -49,7 +49,7 @@ pub fn has_meta(self) -> bool {
 }
 
 #[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
-pub(super) struct MemPlace<Prov: Provenance = AllocId> {
+pub(super) struct MemPlace<Prov: Provenance = CtfeProvenance> {
     /// The pointer can be a pure integer, with the `None` provenance.
     pub ptr: Pointer<Option<Prov>>,
     /// Metadata for unsized places. Interpretation is up to the type.
@@ -100,7 +100,7 @@ fn offset_with_meta_<'mir, 'tcx, M: Machine<'mir, 'tcx, Provenance = Prov>>(
 
 /// A MemPlace with its layout. Constructing it is only possible in this module.
 #[derive(Clone, Hash, Eq, PartialEq)]
-pub struct MPlaceTy<'tcx, Prov: Provenance = AllocId> {
+pub struct MPlaceTy<'tcx, Prov: Provenance = CtfeProvenance> {
     mplace: MemPlace<Prov>,
     pub layout: TyAndLayout<'tcx>,
 }
@@ -179,7 +179,7 @@ fn to_op<'mir, M: Machine<'mir, 'tcx, Provenance = Prov>>(
 }
 
 #[derive(Copy, Clone, Debug)]
-pub(super) enum Place<Prov: Provenance = AllocId> {
+pub(super) enum Place<Prov: Provenance = CtfeProvenance> {
     /// A place referring to a value allocated in the `Memory` system.
     Ptr(MemPlace<Prov>),
 
@@ -195,7 +195,7 @@ pub(super) enum Place<Prov: Provenance = AllocId> {
 }
 
 #[derive(Clone)]
-pub struct PlaceTy<'tcx, Prov: Provenance = AllocId> {
+pub struct PlaceTy<'tcx, Prov: Provenance = CtfeProvenance> {
     place: Place<Prov>, // Keep this private; it helps enforce invariants.
     pub layout: TyAndLayout<'tcx>,
 }
diff --git a/compiler/rustc_const_eval/src/interpret/terminator.rs b/compiler/rustc_const_eval/src/interpret/terminator.rs
index debae6c89024..e48506bd083f 100644
--- a/compiler/rustc_const_eval/src/interpret/terminator.rs
+++ b/compiler/rustc_const_eval/src/interpret/terminator.rs
@@ -18,14 +18,14 @@
 use rustc_target::spec::abi::Abi;
 
 use super::{
-    AllocId, FnVal, ImmTy, InterpCx, InterpResult, MPlaceTy, Machine, OpTy, PlaceTy, Projectable,
-    Provenance, Scalar, StackPopCleanup,
+    CtfeProvenance, FnVal, ImmTy, InterpCx, InterpResult, MPlaceTy, Machine, OpTy, PlaceTy,
+    Projectable, Provenance, Scalar, StackPopCleanup,
 };
 use crate::fluent_generated as fluent;
 
 /// An argment passed to a function.
 #[derive(Clone, Debug)]
-pub enum FnArg<'tcx, Prov: Provenance = AllocId> {
+pub enum FnArg<'tcx, Prov: Provenance = CtfeProvenance> {
     /// Pass a copy of the given operand.
     Copy(OpTy<'tcx, Prov>),
     /// Allow for the argument to be passed in-place: destroy the value originally stored at that place and
diff --git a/compiler/rustc_middle/src/mir/consts.rs b/compiler/rustc_middle/src/mir/consts.rs
index d38df1b72010..26138157b74e 100644
--- a/compiler/rustc_middle/src/mir/consts.rs
+++ b/compiler/rustc_middle/src/mir/consts.rs
@@ -75,7 +75,7 @@ pub enum ConstValue<'tcx> {
 
 impl<'tcx> ConstValue<'tcx> {
     #[inline]
-    pub fn try_to_scalar(&self) -> Option<Scalar<AllocId>> {
+    pub fn try_to_scalar(&self) -> Option<Scalar> {
         match *self {
             ConstValue::Indirect { .. } | ConstValue::Slice { .. } | ConstValue::ZeroSized => None,
             ConstValue::Scalar(val) => Some(val),
@@ -161,8 +161,8 @@ pub fn try_get_slice_bytes_for_diagnostics(&self, tcx: TyCtxt<'tcx>) -> Option<&
                     return Some(&[]);
                 }
                 // Non-empty slice, must have memory. We know this is a relative pointer.
-                let (inner_alloc_id, offset) = ptr.into_parts();
-                let data = tcx.global_alloc(inner_alloc_id?).unwrap_memory();
+                let (inner_prov, offset) = ptr.into_parts();
+                let data = tcx.global_alloc(inner_prov?.alloc_id()).unwrap_memory();
                 (data, offset.bytes(), offset.bytes() + len)
             }
         };
diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs
index 09e56b2e4a82..2a9e0847f439 100644
--- a/compiler/rustc_middle/src/mir/interpret/allocation.rs
+++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs
@@ -18,9 +18,9 @@
 use rustc_target::abi::{Align, HasDataLayout, Size};
 
 use super::{
-    read_target_uint, write_target_uint, AllocId, BadBytesAccess, InterpError, InterpResult,
-    Pointer, PointerArithmetic, Provenance, ResourceExhaustionInfo, Scalar, ScalarSizeMismatch,
-    UndefinedBehaviorInfo, UnsupportedOpInfo,
+    read_target_uint, write_target_uint, AllocId, BadBytesAccess, CtfeProvenance, InterpError,
+    InterpResult, Pointer, PointerArithmetic, Provenance, ResourceExhaustionInfo, Scalar,
+    ScalarSizeMismatch, UndefinedBehaviorInfo, UnsupportedOpInfo,
 };
 use crate::ty;
 use init_mask::*;
@@ -63,7 +63,7 @@ fn zeroed(size: Size, _align: Align) -> Option<Self> {
 // hashed. (see the `Hash` impl below for more details), so the impl is not derived.
 #[derive(Clone, Eq, PartialEq, TyEncodable, TyDecodable)]
 #[derive(HashStable)]
-pub struct Allocation<Prov: Provenance = AllocId, Extra = (), Bytes = Box<[u8]>> {
+pub struct Allocation<Prov: Provenance = CtfeProvenance, Extra = (), Bytes = Box<[u8]>> {
     /// The actual bytes of the allocation.
     /// Note that the bytes of a pointer represent the offset of the pointer.
     bytes: Bytes,
@@ -336,14 +336,14 @@ pub fn uninit(size: Size, align: Align) -> Self {
     }
 }
 
-impl<Bytes: AllocBytes> Allocation<AllocId, (), Bytes> {
-    /// Adjust allocation from the ones in tcx to a custom Machine instance
-    /// with a different Provenance and Extra type.
+impl<Bytes: AllocBytes> Allocation<CtfeProvenance, (), Bytes> {
+    /// Adjust allocation from the ones in `tcx` to a custom Machine instance
+    /// with a different `Provenance` and `Extra` type.
     pub fn adjust_from_tcx<Prov: Provenance, Extra, Err>(
         self,
         cx: &impl HasDataLayout,
         extra: Extra,
-        mut adjust_ptr: impl FnMut(Pointer<AllocId>) -> Result<Pointer<Prov>, Err>,
+        mut adjust_ptr: impl FnMut(Pointer<CtfeProvenance>) -> Result<Pointer<Prov>, Err>,
     ) -> Result<Allocation<Prov, Extra, Bytes>, Err> {
         let mut bytes = self.bytes;
         // Adjust provenance of pointers stored in this allocation.
diff --git a/compiler/rustc_middle/src/mir/interpret/allocation/provenance_map.rs b/compiler/rustc_middle/src/mir/interpret/allocation/provenance_map.rs
index d504af6b7ead..9459af490e32 100644
--- a/compiler/rustc_middle/src/mir/interpret/allocation/provenance_map.rs
+++ b/compiler/rustc_middle/src/mir/interpret/allocation/provenance_map.rs
@@ -6,14 +6,14 @@
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_target::abi::{HasDataLayout, Size};
 
-use super::{alloc_range, AllocError, AllocId, AllocRange, AllocResult, Provenance};
+use super::{alloc_range, AllocError, AllocRange, AllocResult, CtfeProvenance, Provenance};
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 
 /// Stores the provenance information of pointers stored in memory.
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 #[derive(HashStable)]
-pub struct ProvenanceMap<Prov = AllocId> {
-    /// Provenance in this map applies from the given offset for an entire pointer-size worth of
+pub struct ProvenanceMap<Prov = CtfeProvenance> {
+    /// `Provenance` in this map applies from the given offset for an entire pointer-size worth of
     /// bytes. Two entries in this map are always at least a pointer size apart.
     ptrs: SortedMap<Size, Prov>,
     /// Provenance in this map only applies to the given single byte.
@@ -22,18 +22,19 @@ pub struct ProvenanceMap<Prov = AllocId> {
     bytes: Option<Box<SortedMap<Size, Prov>>>,
 }
 
+// These impls are generic over `Prov` since `CtfeProvenance` is only decodable/encodable
+// for some particular `D`/`S`.
 impl<D: Decoder, Prov: Provenance + Decodable<D>> Decodable<D> for ProvenanceMap<Prov> {
     fn decode(d: &mut D) -> Self {
-        assert!(!Prov::OFFSET_IS_ADDR); // only `AllocId` is ever serialized
+        assert!(!Prov::OFFSET_IS_ADDR); // only `CtfeProvenance` is ever serialized
         Self { ptrs: Decodable::decode(d), bytes: None }
     }
 }
-
 impl<S: Encoder, Prov: Provenance + Encodable<S>> Encodable<S> for ProvenanceMap<Prov> {
     fn encode(&self, s: &mut S) {
         let Self { ptrs, bytes } = self;
-        assert!(!Prov::OFFSET_IS_ADDR); // only `AllocId` is ever serialized
-        debug_assert!(bytes.is_none());
+        assert!(!Prov::OFFSET_IS_ADDR); // only `CtfeProvenance` is ever serialized
+        debug_assert!(bytes.is_none()); // without `OFFSET_IS_ADDR`, this is always empty
         ptrs.encode(s)
     }
 }
@@ -54,10 +55,10 @@ impl ProvenanceMap {
     /// Give access to the ptr-sized provenances (which can also be thought of as relocations, and
     /// indeed that is how codegen treats them).
     ///
-    /// Only exposed with `AllocId` provenance, since it panics if there is bytewise provenance.
+    /// Only exposed with `CtfeProvenance` provenance, since it panics if there is bytewise provenance.
     #[inline]
-    pub fn ptrs(&self) -> &SortedMap<Size, AllocId> {
-        debug_assert!(self.bytes.is_none()); // `AllocId::OFFSET_IS_ADDR` is false so this cannot fail
+    pub fn ptrs(&self) -> &SortedMap<Size, CtfeProvenance> {
+        debug_assert!(self.bytes.is_none()); // `CtfeProvenance::OFFSET_IS_ADDR` is false so this cannot fail
         &self.ptrs
     }
 }
diff --git a/compiler/rustc_middle/src/mir/interpret/error.rs b/compiler/rustc_middle/src/mir/interpret/error.rs
index 44b22e2d3838..41386793987f 100644
--- a/compiler/rustc_middle/src/mir/interpret/error.rs
+++ b/compiler/rustc_middle/src/mir/interpret/error.rs
@@ -290,7 +290,7 @@ fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
 // These types have nice `Debug` output so we can just use them in diagnostics.
 impl_into_diagnostic_arg_through_debug! {
     AllocId,
-    Pointer,
+    Pointer<AllocId>,
     AllocRange,
 }
 
@@ -323,7 +323,7 @@ pub enum UndefinedBehaviorInfo<'tcx> {
     /// Invalid metadata in a wide pointer
     InvalidMeta(InvalidMetaKind),
     /// Reading a C string that does not end within its allocation.
-    UnterminatedCString(Pointer),
+    UnterminatedCString(Pointer<AllocId>),
     /// Using a pointer after it got freed.
     PointerUseAfterFree(AllocId, CheckInAllocMsg),
     /// Used a pointer outside the bounds it is valid for.
@@ -350,11 +350,11 @@ pub enum UndefinedBehaviorInfo<'tcx> {
     /// Using a non-character `u32` as character.
     InvalidChar(u32),
     /// The tag of an enum does not encode an actual discriminant.
-    InvalidTag(Scalar),
+    InvalidTag(Scalar<AllocId>),
     /// Using a pointer-not-to-a-function as function pointer.
-    InvalidFunctionPointer(Pointer),
+    InvalidFunctionPointer(Pointer<AllocId>),
     /// Using a pointer-not-to-a-vtable as vtable pointer.
-    InvalidVTablePointer(Pointer),
+    InvalidVTablePointer(Pointer<AllocId>),
     /// Using a string that is not valid UTF-8,
     InvalidStr(std::str::Utf8Error),
     /// Using uninitialized data where it is not allowed.
diff --git a/compiler/rustc_middle/src/mir/interpret/mod.rs b/compiler/rustc_middle/src/mir/interpret/mod.rs
index e5f891fcc91d..2db560085534 100644
--- a/compiler/rustc_middle/src/mir/interpret/mod.rs
+++ b/compiler/rustc_middle/src/mir/interpret/mod.rs
@@ -157,7 +157,7 @@ macro_rules! throw_ub_custom {
     InitChunk, InitChunkIter,
 };
 
-pub use self::pointer::{Pointer, PointerArithmetic, Provenance};
+pub use self::pointer::{CtfeProvenance, Pointer, PointerArithmetic, Provenance};
 
 /// Uniquely identifies one of the following:
 /// - A constant
diff --git a/compiler/rustc_middle/src/mir/interpret/pointer.rs b/compiler/rustc_middle/src/mir/interpret/pointer.rs
index 1c9ce1cb1308..a7f54aacdf26 100644
--- a/compiler/rustc_middle/src/mir/interpret/pointer.rs
+++ b/compiler/rustc_middle/src/mir/interpret/pointer.rs
@@ -3,7 +3,7 @@
 use rustc_macros::HashStable;
 use rustc_target::abi::{HasDataLayout, Size};
 
-use std::fmt;
+use std::{fmt, num::NonZeroU64};
 
 ////////////////////////////////////////////////////////////////////////////////
 // Pointer arithmetic
@@ -141,6 +141,78 @@ fn fmt(ptr: &Pointer<Self>, f: &mut fmt::Formatter<'_>) -> fmt::Result
     fn join(left: Option<Self>, right: Option<Self>) -> Option<Self>;
 }
 
+/// The type of provenance in the compile-time interpreter.
+/// This is a packed representation of an `AllocId` and an `immutable: bool`.
+#[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]
+pub struct CtfeProvenance(NonZeroU64);
+
+impl From<AllocId> for CtfeProvenance {
+    fn from(value: AllocId) -> Self {
+        let prov = CtfeProvenance(value.0);
+        assert!(!prov.immutable(), "`AllocId` with the highest bit set cannot be used in CTFE");
+        prov
+    }
+}
+
+impl fmt::Debug for CtfeProvenance {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // FIXME print "immutable" bit
+        self.alloc_id().fmt(f)
+    }
+}
+
+const IMMUTABLE_MASK: u64 = 1 << 63; // the highest bit
+
+impl CtfeProvenance {
+    /// Returns the `AllocId` of this provenance.
+    #[inline(always)]
+    pub fn alloc_id(self) -> AllocId {
+        AllocId(NonZeroU64::new(self.0.get() & !IMMUTABLE_MASK).unwrap())
+    }
+
+    /// Returns whether this provenance is immutable.
+    #[inline]
+    pub fn immutable(self) -> bool {
+        self.0.get() & IMMUTABLE_MASK != 0
+    }
+
+    /// Returns an immutable version of this provenance.
+    #[inline]
+    pub fn as_immutable(self) -> Self {
+        CtfeProvenance(self.0 | IMMUTABLE_MASK)
+    }
+}
+
+impl Provenance for CtfeProvenance {
+    // With the `AllocId` as provenance, the `offset` is interpreted *relative to the allocation*,
+    // so ptr-to-int casts are not possible (since we do not know the global physical offset).
+    const OFFSET_IS_ADDR: bool = false;
+
+    fn fmt(ptr: &Pointer<Self>, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // FIXME print "immutable" bit
+        // Forward `alternate` flag to `alloc_id` printing.
+        if f.alternate() {
+            write!(f, "{:#?}", ptr.provenance.alloc_id())?;
+        } else {
+            write!(f, "{:?}", ptr.provenance.alloc_id())?;
+        }
+        // Print offset only if it is non-zero.
+        if ptr.offset.bytes() > 0 {
+            write!(f, "+{:#x}", ptr.offset.bytes())?;
+        }
+        Ok(())
+    }
+
+    fn get_alloc_id(self) -> Option<AllocId> {
+        Some(self.alloc_id())
+    }
+
+    fn join(_left: Option<Self>, _right: Option<Self>) -> Option<Self> {
+        panic!("merging provenance is not supported when `OFFSET_IS_ADDR` is false")
+    }
+}
+
+// We also need this impl so that one can debug-print `Pointer<AllocId>`
 impl Provenance for AllocId {
     // With the `AllocId` as provenance, the `offset` is interpreted *relative to the allocation*,
     // so ptr-to-int casts are not possible (since we do not know the global physical offset).
@@ -174,7 +246,7 @@ fn join(_left: Option<Self>, _right: Option<Self>) -> Option<Self> {
 /// Pointers are "tagged" with provenance information; typically the `AllocId` they belong to.
 #[derive(Copy, Clone, Eq, PartialEq, TyEncodable, TyDecodable, Hash)]
 #[derive(HashStable)]
-pub struct Pointer<Prov = AllocId> {
+pub struct Pointer<Prov = CtfeProvenance> {
     pub(super) offset: Size, // kept private to avoid accidental misinterpretation (meaning depends on `Prov` type)
     pub provenance: Prov,
 }
@@ -182,7 +254,7 @@ pub struct Pointer<Prov = AllocId> {
 static_assert_size!(Pointer, 16);
 // `Option<Prov>` pointers are also passed around quite a bit
 // (but not stored in permanent machine state).
-static_assert_size!(Pointer<Option<AllocId>>, 16);
+static_assert_size!(Pointer<Option<CtfeProvenance>>, 16);
 
 // We want the `Debug` output to be readable as it is used by `derive(Debug)` for
 // all the Miri types.
@@ -215,7 +287,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 impl From<AllocId> for Pointer {
     #[inline(always)]
     fn from(alloc_id: AllocId) -> Self {
-        Pointer::new(alloc_id, Size::ZERO)
+        Pointer::new(alloc_id.into(), Size::ZERO)
     }
 }
 
diff --git a/compiler/rustc_middle/src/mir/interpret/value.rs b/compiler/rustc_middle/src/mir/interpret/value.rs
index 0d548f886361..5ecff04f3ae3 100644
--- a/compiler/rustc_middle/src/mir/interpret/value.rs
+++ b/compiler/rustc_middle/src/mir/interpret/value.rs
@@ -11,7 +11,10 @@
 
 use crate::ty::ScalarInt;
 
-use super::{AllocId, InterpResult, Pointer, PointerArithmetic, Provenance, ScalarSizeMismatch};
+use super::{
+    AllocId, CtfeProvenance, InterpResult, Pointer, PointerArithmetic, Provenance,
+    ScalarSizeMismatch,
+};
 
 /// A `Scalar` represents an immediate, primitive value existing outside of a
 /// `memory::Allocation`. It is in many ways like a small chunk of an `Allocation`, up to 16 bytes in
@@ -22,7 +25,7 @@
 /// Do *not* match on a `Scalar`! Use the various `to_*` methods instead.
 #[derive(Clone, Copy, Eq, PartialEq, TyEncodable, TyDecodable, Hash)]
 #[derive(HashStable)]
-pub enum Scalar<Prov = AllocId> {
+pub enum Scalar<Prov = CtfeProvenance> {
     /// The raw bytes of a simple value.
     Int(ScalarInt),
 
@@ -267,6 +270,9 @@ pub fn to_pointer(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, Pointer<O
     /// Will perform ptr-to-int casts if needed and possible.
     /// If that fails, we know the offset is relative, so we return an "erased" Scalar
     /// (which is useful for error messages but not much else).
+    ///
+    /// The error type is `AllocId`, not `CtfeProvenance`, since `AllocId` is the "minimal"
+    /// component all provenance types must have.
     #[inline]
     pub fn try_to_int(self) -> Result<ScalarInt, Scalar<AllocId>> {
         match self {
diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index 1974a35cb85c..bfaa0d88fc09 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -1337,13 +1337,13 @@ pub fn write_allocations<'tcx>(
     fn alloc_ids_from_alloc(
         alloc: ConstAllocation<'_>,
     ) -> impl DoubleEndedIterator<Item = AllocId> + '_ {
-        alloc.inner().provenance().ptrs().values().copied()
+        alloc.inner().provenance().ptrs().values().map(|p| p.alloc_id())
     }
 
     fn alloc_ids_from_const_val(val: ConstValue<'_>) -> impl Iterator<Item = AllocId> + '_ {
         match val {
             ConstValue::Scalar(interpret::Scalar::Ptr(ptr, _)) => {
-                Either::Left(std::iter::once(ptr.provenance))
+                Either::Left(std::iter::once(ptr.provenance.alloc_id()))
             }
             ConstValue::Scalar(interpret::Scalar::Int { .. }) => Either::Right(std::iter::empty()),
             ConstValue::ZeroSized => Either::Right(std::iter::empty()),
diff --git a/compiler/rustc_middle/src/mir/statement.rs b/compiler/rustc_middle/src/mir/statement.rs
index be35a54be584..f929a5cec253 100644
--- a/compiler/rustc_middle/src/mir/statement.rs
+++ b/compiler/rustc_middle/src/mir/statement.rs
@@ -381,7 +381,7 @@ pub fn const_fn_def(&self) -> Option<(DefId, GenericArgsRef<'tcx>)> {
 impl<'tcx> ConstOperand<'tcx> {
     pub fn check_static_ptr(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
         match self.const_.try_to_scalar() {
-            Some(Scalar::Ptr(ptr, _size)) => match tcx.global_alloc(ptr.provenance) {
+            Some(Scalar::Ptr(ptr, _size)) => match tcx.global_alloc(ptr.provenance.alloc_id()) {
                 GlobalAlloc::Static(def_id) => {
                     assert!(!tcx.is_thread_local_static(def_id));
                     Some(def_id)
diff --git a/compiler/rustc_middle/src/query/erase.rs b/compiler/rustc_middle/src/query/erase.rs
index cdde6a596a80..b9200f1abf16 100644
--- a/compiler/rustc_middle/src/query/erase.rs
+++ b/compiler/rustc_middle/src/query/erase.rs
@@ -264,6 +264,7 @@ impl EraseType for $ty {
     rustc_middle::middle::stability::DeprecationEntry,
     rustc_middle::mir::ConstQualifs,
     rustc_middle::mir::interpret::AllocId,
+    rustc_middle::mir::interpret::CtfeProvenance,
     rustc_middle::mir::interpret::ErrorHandled,
     rustc_middle::mir::interpret::LitToConstError,
     rustc_middle::thir::ExprId,
diff --git a/compiler/rustc_middle/src/ty/codec.rs b/compiler/rustc_middle/src/ty/codec.rs
index 81cf41889d49..69ae05ca820a 100644
--- a/compiler/rustc_middle/src/ty/codec.rs
+++ b/compiler/rustc_middle/src/ty/codec.rs
@@ -8,6 +8,7 @@
 
 use crate::arena::ArenaAllocatable;
 use crate::infer::canonical::{CanonicalVarInfo, CanonicalVarInfos};
+use crate::mir::interpret::CtfeProvenance;
 use crate::mir::{
     self,
     interpret::{AllocId, ConstAllocation},
@@ -164,6 +165,13 @@ fn encode(&self, e: &mut E) {
     }
 }
 
+impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for CtfeProvenance {
+    fn encode(&self, e: &mut E) {
+        self.alloc_id().encode(e);
+        self.immutable().encode(e);
+    }
+}
+
 impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for ty::ParamEnv<'tcx> {
     fn encode(&self, e: &mut E) {
         self.caller_bounds().encode(e);
@@ -295,6 +303,15 @@ fn decode(decoder: &mut D) -> Self {
     }
 }
 
+impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for CtfeProvenance {
+    fn decode(decoder: &mut D) -> Self {
+        let alloc_id: AllocId = Decodable::decode(decoder);
+        let prov = CtfeProvenance::from(alloc_id);
+        let immutable: bool = Decodable::decode(decoder);
+        if immutable { prov.as_immutable() } else { prov }
+    }
+}
+
 impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for ty::SymbolName<'tcx> {
     fn decode(decoder: &mut D) -> Self {
         ty::SymbolName::new(decoder.interner(), decoder.read_str())
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index a216cc28c8a9..e48840fac205 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -1,5 +1,5 @@
 use crate::middle::resolve_bound_vars as rbv;
-use crate::mir::interpret::{AllocId, ErrorHandled, LitToConstInput, Scalar};
+use crate::mir::interpret::{ErrorHandled, LitToConstInput, Scalar};
 use crate::ty::{self, GenericArgs, ParamEnv, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt};
 use rustc_data_structures::intern::Interned;
 use rustc_error_messages::MultiSpan;
@@ -413,7 +413,7 @@ pub fn try_to_valtree(self) -> Option<ty::ValTree<'tcx>> {
     }
 
     #[inline]
-    pub fn try_to_scalar(self) -> Option<Scalar<AllocId>> {
+    pub fn try_to_scalar(self) -> Option<Scalar> {
         self.try_to_valtree()?.try_to_scalar()
     }
 
diff --git a/compiler/rustc_middle/src/ty/consts/valtree.rs b/compiler/rustc_middle/src/ty/consts/valtree.rs
index fb7bf78bafe3..ffa0e89c4732 100644
--- a/compiler/rustc_middle/src/ty/consts/valtree.rs
+++ b/compiler/rustc_middle/src/ty/consts/valtree.rs
@@ -1,5 +1,5 @@
 use super::ScalarInt;
-use crate::mir::interpret::{AllocId, Scalar};
+use crate::mir::interpret::Scalar;
 use crate::ty::{self, Ty, TyCtxt};
 use rustc_macros::{HashStable, TyDecodable, TyEncodable};
 
@@ -67,7 +67,7 @@ pub fn from_scalar_int(i: ScalarInt) -> Self {
         Self::Leaf(i)
     }
 
-    pub fn try_to_scalar(self) -> Option<Scalar<AllocId>> {
+    pub fn try_to_scalar(self) -> Option<Scalar> {
         self.try_to_scalar_int().map(Scalar::Int)
     }
 
diff --git a/compiler/rustc_middle/src/ty/impls_ty.rs b/compiler/rustc_middle/src/ty/impls_ty.rs
index 59c0639fea21..129d947697e8 100644
--- a/compiler/rustc_middle/src/ty/impls_ty.rs
+++ b/compiler/rustc_middle/src/ty/impls_ty.rs
@@ -84,6 +84,14 @@ fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHas
     }
 }
 
+// CtfeProvenance is an AllocId and a bool.
+impl<'a> HashStable<StableHashingContext<'a>> for mir::interpret::CtfeProvenance {
+    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
+        self.alloc_id().hash_stable(hcx, hasher);
+        self.immutable().hash_stable(hcx, hasher);
+    }
+}
+
 impl<'a> ToStableHashKey<StableHashingContext<'a>> for region::Scope {
     type KeyType = region::Scope;
 
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 68dd8dee87c4..e9c3bdb227a8 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -1410,14 +1410,14 @@ fn pretty_print_const_scalar_ptr(
     ) -> Result<(), PrintError> {
         define_scoped_cx!(self);
 
-        let (alloc_id, offset) = ptr.into_parts();
+        let (prov, offset) = ptr.into_parts();
         match ty.kind() {
             // Byte strings (&[u8; N])
             ty::Ref(_, inner, _) => {
                 if let ty::Array(elem, len) = inner.kind() {
                     if let ty::Uint(ty::UintTy::U8) = elem.kind() {
                         if let ty::ConstKind::Value(ty::ValTree::Leaf(int)) = len.kind() {
-                            match self.tcx().try_get_global_alloc(alloc_id) {
+                            match self.tcx().try_get_global_alloc(prov.alloc_id()) {
                                 Some(GlobalAlloc::Memory(alloc)) => {
                                     let len = int.assert_bits(self.tcx().data_layout.pointer_size);
                                     let range =
@@ -1447,7 +1447,7 @@ fn pretty_print_const_scalar_ptr(
                 // FIXME: We should probably have a helper method to share code with the "Byte strings"
                 // printing above (which also has to handle pointers to all sorts of things).
                 if let Some(GlobalAlloc::Function(instance)) =
-                    self.tcx().try_get_global_alloc(alloc_id)
+                    self.tcx().try_get_global_alloc(prov.alloc_id())
                 {
                     self.typed_value(
                         |this| this.print_value_path(instance.def_id(), instance.args),
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index 971acda33e23..0f19a2fd822a 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -440,8 +440,9 @@ fn fmt<Infcx: InferCtxtLike<Interner = TyCtxt<'tcx>>>(
     crate::ty::ClosureKind,
     crate::ty::ParamConst,
     crate::ty::ParamTy,
-    interpret::Scalar,
     interpret::AllocId,
+    interpret::CtfeProvenance,
+    interpret::Scalar,
     rustc_target::abi::Size,
 }
 
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index b96125de95e7..80ecb13aa635 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -240,10 +240,7 @@ fn before_access_global(
     }
 
     #[inline(always)]
-    fn expose_ptr(
-        _ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        _ptr: Pointer<AllocId>,
-    ) -> InterpResult<'tcx> {
+    fn expose_ptr(_ecx: &mut InterpCx<'mir, 'tcx, Self>, _ptr: Pointer) -> InterpResult<'tcx> {
         throw_machine_stop_str!("exposing pointers isn't supported in ConstProp")
     }
 
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs
index 735960f31b37..1a5979ef714b 100644
--- a/compiler/rustc_mir_transform/src/gvn.rs
+++ b/compiler/rustc_mir_transform/src/gvn.rs
@@ -388,7 +388,9 @@ fn eval_to_const(&mut self, value: VnIndex) -> Option<OpTy<'tcx>> {
                         self.ecx.copy_op(op, &field_dest, /*allow_transmute*/ false).ok()?;
                     }
                     self.ecx.write_discriminant(variant.unwrap_or(FIRST_VARIANT), &dest).ok()?;
-                    self.ecx.alloc_mark_immutable(dest.ptr().provenance.unwrap()).ok()?;
+                    self.ecx
+                        .alloc_mark_immutable(dest.ptr().provenance.unwrap().alloc_id())
+                        .ok()?;
                     dest.into()
                 } else {
                     return None;
@@ -928,7 +930,8 @@ fn op_to_prop_const<'tcx>(
         }
 
         let pointer = mplace.ptr().into_pointer_or_addr().ok()?;
-        let (alloc_id, offset) = pointer.into_parts();
+        let (prov, offset) = pointer.into_parts();
+        let alloc_id = prov.alloc_id();
         intern_const_alloc_for_constprop(ecx, alloc_id).ok()?;
         if matches!(ecx.tcx.global_alloc(alloc_id), GlobalAlloc::Memory(_)) {
             // `alloc_id` may point to a static. Codegen will choke on an `Indirect` with anything
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index b882a038711c..3a7cc405ca75 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -385,8 +385,8 @@ fn collect_items_rec<'tcx>(
             recursion_depth_reset = None;
 
             if let Ok(alloc) = tcx.eval_static_initializer(def_id) {
-                for &id in alloc.inner().provenance().ptrs().values() {
-                    collect_alloc(tcx, id, &mut used_items);
+                for &prov in alloc.inner().provenance().ptrs().values() {
+                    collect_alloc(tcx, prov.alloc_id(), &mut used_items);
                 }
             }
 
@@ -1363,9 +1363,9 @@ fn collect_alloc<'tcx>(tcx: TyCtxt<'tcx>, alloc_id: AllocId, output: &mut MonoIt
         }
         GlobalAlloc::Memory(alloc) => {
             trace!("collecting {:?} with {:#?}", alloc_id, alloc);
-            for &inner in alloc.inner().provenance().ptrs().values() {
+            for &prov in alloc.inner().provenance().ptrs().values() {
                 rustc_data_structures::stack::ensure_sufficient_stack(|| {
-                    collect_alloc(tcx, inner, output);
+                    collect_alloc(tcx, prov.alloc_id(), output);
                 });
             }
         }
@@ -1440,12 +1440,12 @@ fn collect_const_value<'tcx>(
 ) {
     match value {
         mir::ConstValue::Scalar(Scalar::Ptr(ptr, _size)) => {
-            collect_alloc(tcx, ptr.provenance, output)
+            collect_alloc(tcx, ptr.provenance.alloc_id(), output)
         }
         mir::ConstValue::Indirect { alloc_id, .. } => collect_alloc(tcx, alloc_id, output),
         mir::ConstValue::Slice { data, meta: _ } => {
-            for &id in data.inner().provenance().ptrs().values() {
-                collect_alloc(tcx, id, output);
+            for &prov in data.inner().provenance().ptrs().values() {
+                collect_alloc(tcx, prov.alloc_id(), output);
             }
         }
         _ => {}
diff --git a/compiler/rustc_smir/src/rustc_smir/alloc.rs b/compiler/rustc_smir/src/rustc_smir/alloc.rs
index 63a2a145069e..850a52ce275f 100644
--- a/compiler/rustc_smir/src/rustc_smir/alloc.rs
+++ b/compiler/rustc_smir/src/rustc_smir/alloc.rs
@@ -47,7 +47,7 @@ pub fn new_allocation<'tcx>(
         }
         ConstValue::Slice { data, meta } => {
             let alloc_id = tables.tcx.reserve_and_set_memory_alloc(data);
-            let ptr = Pointer::new(alloc_id, rustc_target::abi::Size::ZERO);
+            let ptr = Pointer::new(alloc_id.into(), rustc_target::abi::Size::ZERO);
             let scalar_ptr = rustc_middle::mir::interpret::Scalar::from_pointer(ptr, &tables.tcx);
             let scalar_meta =
                 rustc_middle::mir::interpret::Scalar::from_target_usize(meta, &tables.tcx);
@@ -112,7 +112,10 @@ pub(super) fn allocation_filter<'tcx>(
         .iter()
         .filter(|a| a.0 >= alloc_range.start && a.0 <= alloc_range.end())
     {
-        ptrs.push((offset.bytes_usize() - alloc_range.start.bytes_usize(), tables.prov(*prov)));
+        ptrs.push((
+            offset.bytes_usize() - alloc_range.start.bytes_usize(),
+            tables.prov(prov.alloc_id()),
+        ));
     }
     Allocation {
         bytes: bytes,
diff --git a/src/tools/miri/src/diagnostics.rs b/src/tools/miri/src/diagnostics.rs
index fb90559f3d14..ef394b163103 100644
--- a/src/tools/miri/src/diagnostics.rs
+++ b/src/tools/miri/src/diagnostics.rs
@@ -44,7 +44,7 @@ pub enum TerminationInfo {
     },
     DataRace {
         involves_non_atomic: bool,
-        ptr: Pointer,
+        ptr: Pointer<AllocId>,
         op1: RacingOp,
         op2: RacingOp,
         extra: Option<&'static str>,
diff --git a/src/tools/miri/src/intptrcast.rs b/src/tools/miri/src/intptrcast.rs
index cd4d1bcc4647..68c9a7660ebd 100644
--- a/src/tools/miri/src/intptrcast.rs
+++ b/src/tools/miri/src/intptrcast.rs
@@ -256,12 +256,13 @@ fn ptr_from_addr_cast(&self, addr: u64) -> InterpResult<'tcx, Pointer<Option<Pro
     /// Convert a relative (tcx) pointer to a Miri pointer.
     fn ptr_from_rel_ptr(
         &self,
-        ptr: Pointer<AllocId>,
+        ptr: Pointer<CtfeProvenance>,
         tag: BorTag,
     ) -> InterpResult<'tcx, Pointer<Provenance>> {
         let ecx = self.eval_context_ref();
 
-        let (alloc_id, offset) = ptr.into_parts(); // offset is relative (AllocId provenance)
+        let (prov, offset) = ptr.into_parts(); // offset is relative (AllocId provenance)
+        let alloc_id = prov.alloc_id();
         let base_addr = ecx.addr_from_alloc_id(alloc_id)?;
 
         // Add offset with the right kind of pointer-overflowing arithmetic.
diff --git a/src/tools/miri/src/machine.rs b/src/tools/miri/src/machine.rs
index 0826034d75ba..1f201d5b4f54 100644
--- a/src/tools/miri/src/machine.rs
+++ b/src/tools/miri/src/machine.rs
@@ -1175,11 +1175,11 @@ fn adjust_allocation<'b>(
 
     fn adjust_alloc_base_pointer(
         ecx: &MiriInterpCx<'mir, 'tcx>,
-        ptr: Pointer<AllocId>,
+        ptr: Pointer<CtfeProvenance>,
     ) -> InterpResult<'tcx, Pointer<Provenance>> {
+        let alloc_id = ptr.provenance.alloc_id();
         if cfg!(debug_assertions) {
             // The machine promises to never call us on thread-local or extern statics.
-            let alloc_id = ptr.provenance;
             match ecx.tcx.try_get_global_alloc(alloc_id) {
                 Some(GlobalAlloc::Static(def_id)) if ecx.tcx.is_thread_local_static(def_id) => {
                     panic!("adjust_alloc_base_pointer called on thread-local static")
@@ -1190,8 +1190,9 @@ fn adjust_alloc_base_pointer(
                 _ => {}
             }
         }
+        // FIXME: can we somehow preserve the immutability of `ptr`?
         let tag = if let Some(borrow_tracker) = &ecx.machine.borrow_tracker {
-            borrow_tracker.borrow_mut().base_ptr_tag(ptr.provenance, &ecx.machine)
+            borrow_tracker.borrow_mut().base_ptr_tag(alloc_id, &ecx.machine)
         } else {
             // Value does not matter, SB is disabled
             BorTag::default()