Merge from rustc

3 files changed, 23 insertions, 8 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index 730e8977803..3283bcc4c45 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -1034,8 +1034,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     ) -> InterpResult<'tcx> {
         trace!("{:?} is now live", local);
 
-        // We avoid `ty.is_trivially_sized` since that (a) cannot assume WF, so it recurses through
-        // all fields of a tuple, and (b) does something expensive for ADTs.
+        // We avoid `ty.is_trivially_sized` since that does something expensive for ADTs.
         fn is_very_trivially_sized(ty: Ty<'_>) -> bool {
             match ty.kind() {
                 ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
@@ -1054,9 +1053,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 | ty::Closure(..)
                 | ty::CoroutineClosure(..)
                 | ty::Never
-                | ty::Error(_) => true,
+                | ty::Error(_)
+                | ty::Dynamic(_, _, ty::DynStar) => true,
 
-                ty::Str | ty::Slice(_) | ty::Dynamic(..) | ty::Foreign(..) => false,
+                ty::Str | ty::Slice(_) | ty::Dynamic(_, _, ty::Dyn) | ty::Foreign(..) => false,
 
                 ty::Tuple(tys) => tys.last().iter().all(|ty| is_very_trivially_sized(**ty)),
 
diff --git a/compiler/rustc_const_eval/src/interpret/intern.rs b/compiler/rustc_const_eval/src/interpret/intern.rs
index 17bb59aae8f..58eaef65e55 100644
--- a/compiler/rustc_const_eval/src/interpret/intern.rs
+++ b/compiler/rustc_const_eval/src/interpret/intern.rs
@@ -111,6 +111,8 @@ fn intern_as_new_static<'tcx>(
     feed.generics_of(tcx.generics_of(static_id).clone());
     feed.def_ident_span(tcx.def_ident_span(static_id));
     feed.explicit_predicates_of(tcx.explicit_predicates_of(static_id));
+
+    feed.feed_hir()
 }
 
 /// How a constant value should be interned.
@@ -291,7 +293,9 @@ pub fn intern_const_alloc_for_constprop<
         return Ok(());
     }
     // Move allocation to `tcx`.
-    for _ in intern_shallow(ecx, alloc_id, Mutability::Not).map_err(|()| err_ub!(DeadLocal))? {
+    if let Some(_) =
+        (intern_shallow(ecx, alloc_id, Mutability::Not).map_err(|()| err_ub!(DeadLocal))?).next()
+    {
         // We are not doing recursive interning, so we don't currently support provenance.
         // (If this assertion ever triggers, we should just implement a
         // proper recursive interning loop -- or just call `intern_const_alloc_recursive`.
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index a6ca4b2e0de..9b1d9cf932b 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -1159,11 +1159,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         };
 
         // Side-step AllocRef and directly access the underlying bytes more efficiently.
-        // (We are staying inside the bounds here so all is good.)
+        // (We are staying inside the bounds here and all bytes do get overwritten so all is good.)
         let alloc_id = alloc_ref.alloc_id;
         let bytes = alloc_ref
             .alloc
-            .get_bytes_mut(&alloc_ref.tcx, alloc_ref.range)
+            .get_bytes_unchecked_for_overwrite(&alloc_ref.tcx, alloc_ref.range)
             .map_err(move |e| e.to_interp_error(alloc_id))?;
         // `zip` would stop when the first iterator ends; we want to definitely
         // cover all of `bytes`.
@@ -1184,6 +1184,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         self.mem_copy_repeatedly(src, dest, size, 1, nonoverlapping)
     }
 
+    /// Performs `num_copies` many copies of `size` many bytes from `src` to `dest + i*size` (where
+    /// `i` is the index of the copy).
+    ///
+    /// Either `nonoverlapping` must be true or `num_copies` must be 1; doing repeated copies that
+    /// may overlap is not supported.
     pub fn mem_copy_repeatedly(
         &mut self,
         src: Pointer<Option<M::Provenance>>,
@@ -1245,8 +1250,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             (dest_alloc_id, dest_prov),
             dest_range,
         )?;
+        // Yes we do overwrite all bytes in `dest_bytes`.
         let dest_bytes = dest_alloc
-            .get_bytes_mut_ptr(&tcx, dest_range)
+            .get_bytes_unchecked_for_overwrite_ptr(&tcx, dest_range)
             .map_err(|e| e.to_interp_error(dest_alloc_id))?
             .as_mut_ptr();
 
@@ -1280,6 +1286,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     }
                 }
             }
+            if num_copies > 1 {
+                assert!(nonoverlapping, "multi-copy only supported in non-overlapping mode");
+            }
 
             let size_in_bytes = size.bytes_usize();
             // For particularly large arrays (where this is perf-sensitive) it's common that
@@ -1292,6 +1301,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             } else if src_alloc_id == dest_alloc_id {
                 let mut dest_ptr = dest_bytes;
                 for _ in 0..num_copies {
+                    // Here we rely on `src` and `dest` being non-overlapping if there is more than
+                    // one copy.
                     ptr::copy(src_bytes, dest_ptr, size_in_bytes);
                     dest_ptr = dest_ptr.add(size_in_bytes);
                 }