Bug 1126754 - Correctly note new pn_tail; factor out ParseNode::prepend (r=jandem)

--HG--
extra : rebase_source : 29a9a9b1e81e218d0abd353a71b08ad972d5b084

js/src/frontend/FullParseHandler.h

@@ -382,10 +382,7 @@ class FullParseHandler
         if (!initialYield)
             return false;
 
-        initialYield->pn_next = stmtList->pn_head;
-        stmtList->pn_head = initialYield;
-        stmtList->pn_count++;
-
+        stmtList->prepend(initialYield);
         return true;
     }
 

js/src/frontend/ParseNode.h

@@ -848,6 +848,15 @@ class ParseNode
         pn_count++;
     }
 
+    void prepend(ParseNode *pn) {
+        MOZ_ASSERT(pn_arity == PN_LIST);
+        pn->pn_next = pn_head;
+        pn_head = pn;
+        if (pn_tail == &pn_head)
+            pn_tail = &pn->pn_next;
+        pn_count++;
+    }
+
     void checkListConsistency()
 #ifndef DEBUG
     {}

js/src/frontend/Parser.cpp

@@ -2253,11 +2253,7 @@ Parser<FullParseHandler>::finishFunctionDefinition(ParseNode *pn, FunctionBox *f
         if (!item)
             return false;
 
-        item->pn_next = body->pn_head;
-        body->pn_head = item;
-        if (body->pn_tail == &body->pn_head)
-            body->pn_tail = &item->pn_next;
-        ++body->pn_count;
+        body->prepend(item);
         body->pn_xflags |= PNX_DESTRUCT;
     }
 

js/src/jit-test/tests/basic/testBug1126754.js

@@ -0,0 +1,9 @@
+// |jit-test| error:SyntaxError
+
+(function() {
+    with ({}) {}
+    function f() {
+        ({ *h(){} })
+    }
+    function f
+})()