diff --git a/src/librustc_mir/interpret/terminator.rs b/src/librustc_mir/interpret/terminator.rs
index 674051ecd8f16c3232c99cb23d97f056150c6fcc..91d304cf78e529837405199817830a8282701549 100644
--- a/src/librustc_mir/interpret/terminator.rs
+++ b/src/librustc_mir/interpret/terminator.rs
@@ -451,6 +451,7 @@ fn eval_fn_call(
 
     /// Evaluate a const function where all arguments (if any) are zero-sized types.
     /// The evaluation is memoized thanks to the query system.
+    // FIXME: Consider moving this to `const_eval.rs`.
     pub (crate) fn eval_const_fn_call(
         &mut self,
         gid: GlobalId<'tcx>,