From 14ee66acecc353c0b3045d74fbe3addd66f96d79 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Tue, 5 Nov 2019 23:04:17 +0100
Subject: [PATCH] miri cast: avoid unnecessary to_scalar_ptr

---
 src/librustc_mir/interpret/cast.rs  | 4 ++--
 src/librustc_mir/interpret/place.rs | 4 +++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/librustc_mir/interpret/cast.rs b/src/librustc_mir/interpret/cast.rs
index 9ab347957f97..2037305580ad 100644
--- a/src/librustc_mir/interpret/cast.rs
+++ b/src/librustc_mir/interpret/cast.rs
@@ -260,7 +260,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
         match (&src_pointee_ty.kind, &dest_pointee_ty.kind) {
             (&ty::Array(_, length), &ty::Slice(_)) => {
-                let ptr = self.read_immediate(src)?.to_scalar_ptr()?;
+                let ptr = self.read_immediate(src)?.to_scalar()?;
                 // u64 cast is from usize to u64, which is always good
                 let val = Immediate::new_slice(
                     ptr,
@@ -279,7 +279,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             (_, &ty::Dynamic(ref data, _)) => {
                 // Initial cast from sized to dyn trait
                 let vtable = self.get_vtable(src_pointee_ty, data.principal())?;
-                let ptr = self.read_immediate(src)?.to_scalar_ptr()?;
+                let ptr = self.read_immediate(src)?.to_scalar()?;
                 let val = Immediate::new_dyn_trait(ptr, vtable);
                 self.write_immediate(val, dest)
             }
diff --git a/src/librustc_mir/interpret/place.rs b/src/librustc_mir/interpret/place.rs
index 0289c52fd374..d696a595777a 100644
--- a/src/librustc_mir/interpret/place.rs
+++ b/src/librustc_mir/interpret/place.rs
@@ -287,7 +287,9 @@ where
         &self,
         val: ImmTy<'tcx, M::PointerTag>,
     ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
-        let pointee_type = val.layout.ty.builtin_deref(true).unwrap().ty;
+        let pointee_type = val.layout.ty.builtin_deref(true)
+            .expect("`ref_to_mplace` called on non-ptr type")
+            .ty;
         let layout = self.layout_of(pointee_type)?;
 
         let mplace = MemPlace {