diff --git a/mozilla/js/src/jsopcode.c b/mozilla/js/src/jsopcode.c
index 14330ca9dc1..4e83f7ca6eb 100644
--- a/mozilla/js/src/jsopcode.c
+++ b/mozilla/js/src/jsopcode.c
@@ -1790,6 +1790,7 @@ Decompile(SprintStack *ss, jsbytecode *pc, intN nb)
 
 #if JS_HAS_GENERATORS
               case JSOP_YIELD:
+                op = JSOP_SETNAME;      /* turn off most parens */
                 rval = POP_STR();
                 todo = (*rval != '\0')
                        ? Sprint(&ss->sprinter,