diff --git a/compiler/rustc_mir/src/transform/simplify.rs b/compiler/rustc_mir/src/transform/simplify.rs
index d2314a9ba158a..3b074f9132fd9 100644
--- a/compiler/rustc_mir/src/transform/simplify.rs
+++ b/compiler/rustc_mir/src/transform/simplify.rs
@@ -422,7 +422,9 @@ impl UsedLocals<'tcx> {
             // A use, not a definition.
             self.visit_place(place, PlaceContext::MutatingUse(MutatingUseContext::Store), location);
         } else {
-            // A definition. Although, it still might use other locals for indexing.
+            // A definition. The base local itself is not visited, so this occurrence is not counted
+            // toward its use count. There might be other locals still, used in an indexing
+            // projection.
             self.super_projection(
                 place.as_ref(),
                 PlaceContext::MutatingUse(MutatingUseContext::Projection),