From 62334acd66dcc0812cb04f4a66792ede7aed9b2a Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Thu, 13 Jul 2017 09:09:45 -0700
Subject: [PATCH] show alignedness of ByRefs; allow converting unaligned ByRef
 to ptr

---
 src/eval_context.rs | 4 ++--
 src/lvalue.rs       | 5 +++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/eval_context.rs b/src/eval_context.rs
index a4ce1d327e3a..1e57adbcf3ea 100644
--- a/src/eval_context.rs
+++ b/src/eval_context.rs
@@ -1575,9 +1575,9 @@ pub(super) fn dump_local(&self, lvalue: Lvalue<'tcx>) {
                 Err(err) => {
                     panic!("Failed to access local: {:?}", err);
                 }
-                Ok(Value::ByRef(ptr, _aligned)) => match ptr.into_inner_primval() {
+                Ok(Value::ByRef(ptr, aligned)) => match ptr.into_inner_primval() {
                     PrimVal::Ptr(ptr) => {
-                        write!(msg, " by ref:").unwrap();
+                        write!(msg, " by {}ref:", if aligned { "" } else { "unaligned " }).unwrap();
                         allocs.push(ptr.alloc_id);
                     },
                     ptr => write!(msg, " integral by ref: {:?}", ptr).unwrap(),
diff --git a/src/lvalue.rs b/src/lvalue.rs
index 79b8d50c96e6..86e09356fd76 100644
--- a/src/lvalue.rs
+++ b/src/lvalue.rs
@@ -86,9 +86,10 @@ pub(super) fn to_ptr_extra_aligned(self) -> (Pointer, LvalueExtra, bool) {
     }
 
     pub(super) fn to_ptr(self) -> EvalResult<'tcx, MemoryPointer> {
-        let (ptr, extra, aligned) = self.to_ptr_extra_aligned();
+        let (ptr, extra, _aligned) = self.to_ptr_extra_aligned();
+        // At this point, we forget about the alignment information -- the lvalue has been turned into a reference,
+        // and no matter where it came from, it now must be aligned.
         assert_eq!(extra, LvalueExtra::None);
-        assert_eq!(aligned, true, "tried converting an unaligned lvalue into a ptr");
         ptr.to_ptr()
     }