diff --git a/src/librustc_middle/mir/interpret/error.rs b/src/librustc_middle/mir/interpret/error.rs
index e6557c9fbd5..084b5fce385 100644
--- a/src/librustc_middle/mir/interpret/error.rs
+++ b/src/librustc_middle/mir/interpret/error.rs
@@ -451,6 +451,8 @@ pub enum UnsupportedOpInfo {
     NoMirFor(DefId),
     /// Encountered a pointer where we needed raw bytes.
     ReadPointerAsBytes,
+
+    // The variants below are only reachable from CTFE/const prop, miri will never emit them.
     /// Encountered raw bytes where we needed a pointer.
     ReadBytesAsPointer,
 }