interpret: fix projecting into an unsized field of a local

new invariant: Place::Local never refers to something unsized

1 files changed, 3 insertions, 2 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/visitor.rs b/compiler/rustc_const_eval/src/interpret/visitor.rs
index 531e2bd3ee0..fc21ad1f183 100644
--- a/compiler/rustc_const_eval/src/interpret/visitor.rs
+++ b/compiler/rustc_const_eval/src/interpret/visitor.rs
@@ -170,8 +170,9 @@ pub trait ValueVisitor<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>>: Sized {
                 }
             }
             FieldsShape::Array { .. } => {
-                for (idx, field) in self.ecx().project_array_fields(v)?.enumerate() {
-                    self.visit_field(v, idx, &field?)?;
+                let mut iter = self.ecx().project_array_fields(v)?;
+                while let Some((idx, field)) = iter.next(self.ecx())? {
+                    self.visit_field(v, idx.try_into().unwrap(), &field)?;
                 }
             }
         }