diff --git a/src/structs.h b/src/structs.h
index 9500139..3c52a63 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -2102,9 +2102,8 @@
     char_u	*eval_tofree_lambda;
 } evalarg_T;
 
-// Flags for expression evaluation.
+// Flag for expression evaluation.
 #define EVAL_EVALUATE	    1	    // when missing don't actually evaluate
-#define EVAL_CONSTANT	    2	    // when not a constant return FAIL
 
 # ifdef FEAT_PROFILE
 /*