diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index a353ebdabb9d1..19bd812ec80c0 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -307,9 +307,9 @@ trait Qualif {
 
 /// Constant containing interior mutability (`UnsafeCell<T>`).
 /// This must be ruled out to make sure that evaluating the constant at compile-time
-/// and run-time would produce the same result. In particular, promotion of temporaries
-/// must not change program behavior; if the promoted could be written to, that would
-/// be a problem.
+/// and at *any point* during the run-time would produce the same result. In particular,
+/// promotion of temporaries must not change program behavior; if the promoted could be
+/// written to, that would be a problem.
 struct HasMutInterior;
 
 impl Qualif for HasMutInterior {