fix handling of base address for TypeId allocations

1 files changed, 13 insertions, 3 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index 20c8e983cea..34297a61648 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -67,8 +67,10 @@ pub enum AllocKind {
     LiveData,
     /// A function allocation (that fn ptrs point to).
     Function,
-    /// A "virtual" allocation, used for vtables and TypeId.
-    Virtual,
+    /// A vtable allocation.
+    VTable,
+    /// A TypeId allocation.
+    TypeId,
     /// A dead allocation.
     Dead,
 }
@@ -952,7 +954,8 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             let kind = match global_alloc {
                 GlobalAlloc::Static { .. } | GlobalAlloc::Memory { .. } => AllocKind::LiveData,
                 GlobalAlloc::Function { .. } => bug!("We already checked function pointers above"),
-                GlobalAlloc::VTable { .. } | GlobalAlloc::TypeId { .. } => AllocKind::Virtual,
+                GlobalAlloc::VTable { .. } => AllocKind::VTable,
+                GlobalAlloc::TypeId { .. } => AllocKind::TypeId,
             };
             return AllocInfo::new(size, align, kind, mutbl);
         }
@@ -1617,6 +1620,13 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 match self.ptr_try_get_alloc_id(ptr, 0) {
                     Ok((alloc_id, offset, _)) => {
                         let info = self.get_alloc_info(alloc_id);
+                        if matches!(info.kind, AllocKind::TypeId) {
+                            // We *could* actually precisely answer this question since here,
+                            // the offset *is* the integer value. But the entire point of making
+                            // this a pointer is not to leak the integer value, so we say everything
+                            // might be null.
+                            return interp_ok(true);
+                        }
                         // If the pointer is in-bounds (including "at the end"), it is definitely not null.
                         if offset <= info.size {
                             return interp_ok(false);