From 0b781b04cb1168095807f86e3b0dfadebf3a1ed2 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Fri, 20 May 2022 15:55:55 +0200
Subject: [PATCH] Ensure we never consider the null pointer dereferencable

---
 compiler/rustc_const_eval/src/interpret/memory.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index 33162a01ed201..5dcd209a8fb30 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -441,6 +441,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         msg,
                     })
                 }
+                // Ensure we never consider the null pointer dereferencable.
+                if M::PointerTag::OFFSET_IS_ADDR {
+                    assert_ne!(ptr.addr(), Size::ZERO);
+                }
                 // Test align. Check this last; if both bounds and alignment are violated
                 // we want the error to be about the bounds.
                 if let Some(align) = align {