diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index 29a231ddfdbf..22bf5663243d 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -6303,29 +6303,29 @@ Parser<ParseHandler>::expr(InHandling inHandling, YieldHandling yieldHandling,
     bool matched;
     if (!tokenStream.matchToken(&matched, TOK_COMMA))
         return null();
-    if (matched) {
-        Node seq = handler.newCommaExpressionList(pn);
-        if (!seq)
+    if (!matched)
+        return pn;
+
+    Node seq = handler.newCommaExpressionList(pn);
+    if (!seq)
+        return null();
+    while (true) {
+        if (handler.isUnparenthesizedYieldExpression(pn)) {
+            report(ParseError, false, pn, JSMSG_BAD_GENERATOR_SYNTAX, js_yield_str);
             return null();
-        while (true) {
-            if (handler.isUnparenthesizedYieldExpression(pn)) {
-                report(ParseError, false, pn, JSMSG_BAD_GENERATOR_SYNTAX, js_yield_str);
-                return null();
-            }
-
-            pn = assignExpr(inHandling, yieldHandling);
-            if (!pn)
-                return null();
-            handler.addList(seq, pn);
-
-            if (!tokenStream.matchToken(&matched, TOK_COMMA))
-                return null();
-            if (!matched)
-                break;
         }
-        return seq;
+
+        pn = assignExpr(inHandling, yieldHandling);
+        if (!pn)
+            return null();
+        handler.addList(seq, pn);
+
+        if (!tokenStream.matchToken(&matched, TOK_COMMA))
+            return null();
+        if (!matched)
+            break;
     }
-    return pn;
+    return seq;
 }
 
 static const JSOp ParseNodeKindToJSOp[] = {