diff --git a/lib/cfg-grammar.y b/lib/cfg-grammar.y
index d5406937ee..365d79fbc4 100644
--- a/lib/cfg-grammar.y
+++ b/lib/cfg-grammar.y
@@ -205,8 +205,7 @@ main_location_print (FILE *yyo, YYLTYPE const * const yylocp)
 %left   ';'
 
 /* operators in the filter language, the order of this determines precedence */
-%right KW_ASSIGN 9000
-%right KW_PLUS_ASSIGN 9001
+%right KW_ASSIGN 9000, KW_PLUS_ASSIGN 9001
 %right '?' ':'
 %right KW_NULL_COALESCING
 %left  KW_OR 9010