Bug 1168992 - Part 4: Convert PNK_SUPERELEM to PNK_ELEM and fix reflection of super[elem]. (r=Waldo)

js/src/builtin/ReflectParse.cpp

@@ -3082,7 +3082,6 @@ ASTSerializer::expression(ParseNode* pn, MutableHandleValue dst)
       case PNK_DELETENAME:
       case PNK_DELETEPROP:
       case PNK_DELETEELEM:
-      case PNK_DELETESUPERELEM:
       case PNK_DELETEEXPR:
       case PNK_TYPEOFNAME:
       case PNK_TYPEOFEXPR:
@@ -3165,22 +3164,19 @@ ASTSerializer::expression(ParseNode* pn, MutableHandleValue dst)
         MOZ_ASSERT(pn->pn_pos.encloses(pn->pn_right->pn_pos));
 
         RootedValue left(cx), right(cx);
-        return expression(pn->pn_left, &left) &&
-               expression(pn->pn_right, &right) &&
+
+        if (pn->as<PropertyByValue>().isSuper()) {
+            if (!builder.super(&pn->pn_left->pn_pos, &left))
+                return false;
+        } else {
+            if (!expression(pn->pn_left, &left))
+                return false;
+        }
+
+        return expression(pn->pn_right, &right) &&
                builder.memberExpression(true, left, right, &pn->pn_pos, dst);
       }
 
-      case PNK_SUPERELEM:
-      {
-        MOZ_ASSERT(pn->pn_pos.encloses(pn->pn_kid->pn_pos));
-
-        RootedValue superBase(cx), expr(cx);
-        RootedAtom superAtom(cx, cx->names().super);
-        return identifier(superAtom, nullptr, &superBase) &&
-               expression(pn->pn_kid, &expr) &&
-               builder.memberExpression(true, superBase, expr, &pn->pn_pos, dst);
-      }
-
       case PNK_CALLSITEOBJ:
       {
         NodeVector raw(cx);

js/src/frontend/BytecodeEmitter.cpp

@@ -2013,7 +2013,6 @@ BytecodeEmitter::checkSideEffects(ParseNode* pn, bool* answer)
       case PNK_DELETENAME:
       case PNK_DELETEPROP:
       case PNK_DELETEELEM:
-      case PNK_DELETESUPERELEM:
         MOZ_ASSERT(pn->isArity(PN_UNARY));
         *answer = true;
         return true;
@@ -2121,12 +2120,6 @@ BytecodeEmitter::checkSideEffects(ParseNode* pn, bool* answer)
         *answer = true;
         return true;
 
-      // Again, getters.
-      case PNK_SUPERELEM:
-        MOZ_ASSERT(pn->isArity(PN_UNARY));
-        *answer = true;
-        return true;
-
       // These affect visible names in this code, or in other code.
       case PNK_IMPORT:
       case PNK_EXPORT_FROM:
@@ -2761,14 +2754,14 @@ BytecodeEmitter::emitElemOperands(ParseNode* pn, JSOp op)
 bool
 BytecodeEmitter::emitSuperElemOperands(ParseNode* pn, SuperElemOptions opts)
 {
-    MOZ_ASSERT(pn->isKind(PNK_SUPERELEM));
+    MOZ_ASSERT(pn->isKind(PNK_ELEM) && pn->as<PropertyByValue>().isSuper());
 
     // The ordering here is somewhat screwy. We need to evaluate the propval
     // first, by spec. Do a little dance to not emit more than one JSOP_THIS.
     // Since JSOP_THIS might throw in derived class constructors, we cannot
     // just push it earlier as the receiver. We have to swap it down instead.
 
-    if (!emitTree(pn->pn_kid))
+    if (!emitTree(pn->pn_right))
         return false;
 
     // We need to convert the key to an object id first, so that we do not do
@@ -2838,99 +2831,77 @@ BytecodeEmitter::emitElemIncDec(ParseNode* pn)
 {
     MOZ_ASSERT(pn->pn_kid->isKind(PNK_ELEM));
 
-    if (!emitElemOperands(pn->pn_kid, JSOP_GETELEM))
-        return false;
+    bool isSuper = pn->pn_kid->as<PropertyByValue>().isSuper();
+
+    if (isSuper) {
+        if (!emitSuperElemOperands(pn->pn_kid, SuperElem_IncDec))
+            return false;
+    } else {
+        if (!emitElemOperands(pn->pn_kid, JSOP_GETELEM))
+            return false;
+    }
 
     bool post;
     JSOp binop = GetIncDecInfo(pn->getKind(), &post);
 
-    /*
-     * We need to convert the key to an object id first, so that we do not do
-     * it inside both the GETELEM and the SETELEM.
-     */
-                                                    // OBJ KEY*
-    if (!emit1(JSOP_TOID))                          // OBJ KEY
+    JSOp getOp;
+    if (isSuper) {
+        // There's no such thing as JSOP_DUP3, so we have to be creative.
+        // Note that pushing things again is no fewer JSOps.
+        if (!emitDupAt(2))                              // KEY THIS OBJ KEY
+            return false;
+        if (!emitDupAt(2))                              // KEY THIS OBJ KEY THIS
+            return false;
+        if (!emitDupAt(2))                              // KEY THIS OBJ KEY THIS OBJ
+            return false;
+        getOp = JSOP_GETELEM_SUPER;
+    } else {
+        // We need to convert the key to an object id first, so that we do not do
+        // it inside both the GETELEM and the SETELEM. In the super case, this is
+        // done by emitSuperElemOperands.
+                                                        // OBJ KEY*
+        if (!emit1(JSOP_TOID))                          // OBJ KEY
+            return false;
+        if (!emit1(JSOP_DUP2))                          // OBJ KEY OBJ KEY
+            return false;
+        getOp = JSOP_GETELEM;
+    }
+    if (!emitElemOpBase(getOp))                         // OBJ KEY V
         return false;
-    if (!emit1(JSOP_DUP2))                          // OBJ KEY OBJ KEY
+    if (!emit1(JSOP_POS))                               // OBJ KEY N
         return false;
-    if (!emitElemOpBase(JSOP_GETELEM))              // OBJ KEY V
+    if (post && !emit1(JSOP_DUP))                       // OBJ KEY N? N
         return false;
-    if (!emit1(JSOP_POS))                           // OBJ KEY N
+    if (!emit1(JSOP_ONE))                               // OBJ KEY N? N 1
         return false;
-    if (post && !emit1(JSOP_DUP))                   // OBJ KEY N? N
-        return false;
-    if (!emit1(JSOP_ONE))                           // OBJ KEY N? N 1
-        return false;
-    if (!emit1(binop))                              // OBJ KEY N? N+1
+    if (!emit1(binop))                                  // OBJ KEY N? N+1
         return false;
 
     if (post) {
-        if (!emit2(JSOP_PICK, 3))                   // KEY N N+1 OBJ
+        if (isSuper) {
+            // We have one more value to rotate around, because of |this|
+            // on the stack
+            if (!emit2(JSOP_PICK, 4))
+                return false;
+        }
+        if (!emit2(JSOP_PICK, 3 + isSuper))             // KEY N N+1 OBJ
             return false;
-        if (!emit2(JSOP_PICK, 3))                   // N N+1 OBJ KEY
+        if (!emit2(JSOP_PICK, 3 + isSuper))             // N N+1 OBJ KEY
             return false;
-        if (!emit2(JSOP_PICK, 2))                   // N OBJ KEY N+1
+        if (!emit2(JSOP_PICK, 2 + isSuper))             // N OBJ KEY N+1
             return false;
     }
 
-    JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM : JSOP_SETELEM;
-    if (!emitElemOpBase(setOp))                     // N? N+1
+    JSOp setOp = isSuper ? (sc->strict() ? JSOP_STRICTSETELEM_SUPER : JSOP_SETELEM_SUPER)
+                         : (sc->strict() ? JSOP_STRICTSETELEM : JSOP_SETELEM);
+    if (!emitElemOpBase(setOp))                         // N? N+1
         return false;
-    if (post && !emit1(JSOP_POP))                   // RESULT
+    if (post && !emit1(JSOP_POP))                       // RESULT
         return false;
 
     return true;
 }
 
-bool
-BytecodeEmitter::emitSuperElemIncDec(ParseNode* pn)
-{
-    MOZ_ASSERT(pn->pn_kid->isKind(PNK_SUPERELEM));
-
-    if (!emitSuperElemOperands(pn->pn_kid, SuperElem_IncDec))
-        return false;
-
-    bool post;
-    JSOp binop = GetIncDecInfo(pn->getKind(), &post);
-
-    // There's no such thing as JSOP_DUP3, so we have to be creative.
-    // Note that pushing things again is no fewer JSOps.
-    if (!emitDupAt(2))                              // KEY THIS OBJ KEY
-        return false;
-    if (!emitDupAt(2))                              // KEY THIS OBJ KEY THIS
-        return false;
-    if (!emitDupAt(2))                              // KEY THIS OBJ KEY THIS OBJ
-        return false;
-    if (!emitElemOpBase(JSOP_GETELEM_SUPER))        // KEY THIS OBJ V
-        return false;
-    if (!emit1(JSOP_POS))                           // KEY THIS OBJ N
-        return false;
-    if (post && !emit1(JSOP_DUP))                   // KEY THIS OBJ N? N
-        return false;
-    if (!emit1(JSOP_ONE))                           // KEY THIS OBJ N? N 1
-        return false;
-    if (!emit1(binop))                              // KEY THIS OBJ N? N+1
-        return false;
-
-    if (post) {
-        if (!emit2(JSOP_PICK, 4))                   // THIS OBJ N N+1 KEY
-            return false;
-        if (!emit2(JSOP_PICK, 4))                   // OBJ N N+1 KEY THIS
-            return false;
-        if (!emit2(JSOP_PICK, 4))                   // N N+1 KEY THIS OBJ
-            return false;
-        if (!emit2(JSOP_PICK, 3))                   // N KEY THIS OBJ N+1
-            return false;
-    }
-
-    JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM_SUPER : JSOP_SETELEM_SUPER;
-    if (!emitElemOpBase(setOp))                     // N? N+1
-        return false;
-    if (post && !emit1(JSOP_POP))                   // RESULT
-        return false;
-
-    return true;
-}
 bool
 BytecodeEmitter::emitNumberOp(double dval)
 {
@@ -3782,19 +3753,15 @@ BytecodeEmitter::emitDestructuringLHS(ParseNode* target, VarEmitOption emitOptio
             // See the comment at `case PNK_DOT:` above. This case,
             // `[a[x]] = [b]`, is handled much the same way. The JSOP_SWAP
             // is emitted by emitElemOperands.
-            JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM : JSOP_SETELEM;
-            if (!emitElemOp(target, setOp))
-                return false;
-            break;
-          }
-
-          case PNK_SUPERELEM:
-          {
-            // See comment above in the PNK_ELEM case. Just as there, the
-            // reordering is handled by emitSuperElemOp.
-            JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM_SUPER : JSOP_SETELEM_SUPER;
-            if (!emitSuperElemOp(target, setOp))
-                return false;
+            if (target->as<PropertyByValue>().isSuper()) {
+                JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM_SUPER : JSOP_SETELEM_SUPER;
+                if (!emitSuperElemOp(target, setOp))
+                    return false;
+            } else {
+                JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM : JSOP_SETELEM;
+                if (!emitElemOp(target, setOp))
+                    return false;
+            }
             break;
           }
 
@@ -4433,16 +4400,17 @@ BytecodeEmitter::emitAssignment(ParseNode* lhs, JSOp op, ParseNode* rhs)
         break;
       case PNK_ELEM:
         MOZ_ASSERT(lhs->isArity(PN_BINARY));
-        if (!emitTree(lhs->pn_left))
-            return false;
-        if (!emitTree(lhs->pn_right))
-            return false;
-        offset += 2;
-        break;
-      case PNK_SUPERELEM:
-        if (!emitSuperElemOperands(lhs))
-            return false;
-        offset += 3;
+        if (lhs->as<PropertyByValue>().isSuper()) {
+            if (!emitSuperElemOperands(lhs))
+                return false;
+            offset += 3;
+        } else {
+            if (!emitTree(lhs->pn_left))
+                return false;
+            if (!emitTree(lhs->pn_right))
+                return false;
+            offset += 2;
+        }
         break;
       case PNK_ARRAY:
       case PNK_OBJECT:
@@ -4515,22 +4483,25 @@ BytecodeEmitter::emitAssignment(ParseNode* lhs, JSOp op, ParseNode* rhs)
                 return false;
             break;
           }
-          case PNK_ELEM:
-            if (!emit1(JSOP_DUP2))
-                return false;
-            if (!emitElemOpBase(JSOP_GETELEM))
-                return false;
-            break;
-          case PNK_SUPERELEM:
-            if (!emitDupAt(2))
-                return false;
-            if (!emitDupAt(2))
-                return false;
-            if (!emitDupAt(2))
-                return false;
-            if (!emitElemOpBase(JSOP_GETELEM_SUPER))
+          case PNK_ELEM: {
+            JSOp elemOp;
+            if (lhs->as<PropertyByValue>().isSuper()) {
+                if (!emitDupAt(2))
+                    return false;
+                if (!emitDupAt(2))
+                    return false;
+                if (!emitDupAt(2))
+                    return false;
+                elemOp = JSOP_GETELEM_SUPER;
+            } else {
+                if (!emit1(JSOP_DUP2))
+                    return false;
+                elemOp = JSOP_GETELEM;
+            }
+            if (!emitElemOpBase(elemOp))
                 return false;
             break;
+          }
           case PNK_CALL:
             /*
              * We just emitted a JSOP_SETCALL (which will always throw) and
@@ -4602,14 +4573,9 @@ BytecodeEmitter::emitAssignment(ParseNode* lhs, JSOp op, ParseNode* rhs)
         break;
       case PNK_ELEM:
       {
-        JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM : JSOP_SETELEM;
-        if (!emit1(setOp))
-            return false;
-        break;
-      }
-      case PNK_SUPERELEM:
-      {
-        JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM_SUPER : JSOP_SETELEM_SUPER;
+        JSOp setOp = lhs->as<PropertyByValue>().isSuper() ?
+                       sc->strict() ? JSOP_STRICTSETELEM_SUPER : JSOP_SETELEM_SUPER :
+                       sc->strict() ? JSOP_STRICTSETELEM : JSOP_SETELEM;
         if (!emit1(setOp))
             return false;
         break;
@@ -6508,34 +6474,26 @@ BytecodeEmitter::emitDeleteElement(ParseNode* node)
     ParseNode* elemExpr = node->pn_kid;
     MOZ_ASSERT(elemExpr->isKind(PNK_ELEM));
 
+    if (elemExpr->as<PropertyByValue>().isSuper()) {
+        // Still have to calculate everything, even though we're gonna throw
+        // since it may have side effects
+        if (!emitTree(elemExpr->pn_right))
+            return false;
+
+        if (!emit1(JSOP_SUPERBASE))
+            return false;
+        if (!emitUint16Operand(JSOP_THROWMSG, JSMSG_CANT_DELETE_SUPER))
+            return false;
+
+        // Another wrinkle: Balance the stack from the emitter's point of view.
+        // Execution will not reach here, as the last bytecode threw.
+        return emit1(JSOP_POP);
+    }
+
     JSOp delOp = sc->strict() ? JSOP_STRICTDELELEM : JSOP_DELELEM;
     return emitElemOp(elemExpr, delOp);
 }
 
-bool
-BytecodeEmitter::emitDeleteSuperElement(ParseNode* node)
-{
-    MOZ_ASSERT(node->isKind(PNK_DELETESUPERELEM));
-    MOZ_ASSERT(node->isArity(PN_UNARY));
-
-    ParseNode* superElemExpr = node->pn_kid;
-    MOZ_ASSERT(superElemExpr->isKind(PNK_SUPERELEM));
-
-    // Still have to calculate everything, even though we're gonna throw
-    // since it may have side effects
-    MOZ_ASSERT(superElemExpr->isArity(PN_UNARY));
-    if (!emitTree(superElemExpr->pn_kid))
-        return false;
-    if (!emit1(JSOP_SUPERBASE))
-        return false;
-    if (!emitUint16Operand(JSOP_THROWMSG, JSMSG_CANT_DELETE_SUPER))
-        return false;
-
-    // Another wrinkle: Balance the stack from the emitter's point of view.
-    // Execution will not reach here, as the last bytecode threw.
-    return emit1(JSOP_POP);
-}
-
 bool
 BytecodeEmitter::emitDeleteExpression(ParseNode* node)
 {
@@ -6704,17 +6662,18 @@ BytecodeEmitter::emitCallOrNew(ParseNode* pn)
         }
         break;
       case PNK_ELEM:
-        if (!emitElemOp(pn2, callop ? JSOP_CALLELEM : JSOP_GETELEM))
-            return false;
-        if (callop) {
-            if (!emit1(JSOP_SWAP))
+        if (pn2->as<PropertyByValue>().isSuper()) {
+            if (!emitSuperElemOp(pn2, JSOP_GETELEM_SUPER, /* isCall = */ callop))
                 return false;
+        } else {
+            if (!emitElemOp(pn2, callop ? JSOP_CALLELEM : JSOP_GETELEM))
+                return false;
+            if (callop) {
+                if (!emit1(JSOP_SWAP))
+                    return false;
+            }
         }
         break;
-      case PNK_SUPERELEM:
-        if (!emitSuperElemOp(pn2, JSOP_GETELEM_SUPER, /* isCall = */ callop))
-            return false;
-        break;
       case PNK_FUNCTION:
         /*
          * Top level lambdas which are immediately invoked should be
@@ -6875,10 +6834,6 @@ BytecodeEmitter::emitIncOrDec(ParseNode* pn)
         if (!emitElemIncDec(pn))
             return false;
         break;
-      case PNK_SUPERELEM:
-        if (!emitSuperElemIncDec(pn))
-            return false;
-        break;
       case PNK_CALL:
         MOZ_ASSERT(pn2->pn_xflags & PNX_SETCALL);
         if (!emitTree(pn2))
@@ -7846,10 +7801,6 @@ BytecodeEmitter::emitTree(ParseNode* pn)
         ok = emitDeleteElement(pn);
         break;
 
-      case PNK_DELETESUPERELEM:
-        ok = emitDeleteSuperElement(pn);
-        break;
-
       case PNK_DELETEEXPR:
         ok = emitDeleteExpression(pn);
         break;
@@ -7865,12 +7816,13 @@ BytecodeEmitter::emitTree(ParseNode* pn)
         break;
 
       case PNK_ELEM:
-        ok = emitElemOp(pn, JSOP_GETELEM);
-        break;
-
-      case PNK_SUPERELEM:
-        if (!emitSuperElemOp(pn, JSOP_GETELEM_SUPER))
-            return false;
+        if (pn->as<PropertyByValue>().isSuper()) {
+            if (!emitSuperElemOp(pn, JSOP_GETELEM_SUPER))
+                return false;
+        } else {
+            if (!emitElemOp(pn, JSOP_GETELEM))
+                return false;
+        }
         break;
 
       case PNK_NEW:

js/src/frontend/BytecodeEmitter.h

@@ -555,7 +555,6 @@ struct BytecodeEmitter
     bool emitDeleteName(ParseNode* pn);
     bool emitDeleteProperty(ParseNode* pn);
     bool emitDeleteElement(ParseNode* pn);
-    bool emitDeleteSuperElement(ParseNode* pn);
     bool emitDeleteExpression(ParseNode* pn);
 
     // |op| must be JSOP_TYPEOF or JSOP_TYPEOFEXPR.
@@ -613,7 +612,6 @@ struct BytecodeEmitter
     enum SuperElemOptions { SuperElem_Get, SuperElem_Set, SuperElem_Call, SuperElem_IncDec };
     bool emitSuperElemOperands(ParseNode* pn, SuperElemOptions opts = SuperElem_Get);
     bool emitSuperElemOp(ParseNode* pn, JSOp op, bool isCall = false);
-    bool emitSuperElemIncDec(ParseNode* pn);
 };
 
 } /* namespace frontend */

js/src/frontend/FoldConstants.cpp

@@ -335,7 +335,6 @@ ContainsHoistedDeclaration(ExclusiveContext* cx, ParseNode* node, bool* result)
       case PNK_DELETENAME:
       case PNK_DELETEPROP:
       case PNK_DELETEELEM:
-      case PNK_DELETESUPERELEM:
       case PNK_DELETEEXPR:
       case PNK_POS:
       case PNK_NEG:
@@ -413,7 +412,6 @@ ContainsHoistedDeclaration(ExclusiveContext* cx, ParseNode* node, bool* result)
       case PNK_CLASSMETHOD:
       case PNK_CLASSMETHODLIST:
       case PNK_CLASSNAMES:
-      case PNK_SUPERELEM:
       case PNK_NEWTARGET:
       case PNK_POSHOLDER:
         MOZ_CRASH("ContainsHoistedDeclaration should have indicated false on "
@@ -631,9 +629,9 @@ static bool
 FoldDeleteElement(ExclusiveContext* cx, ParseNode* node, Parser<FullParseHandler>& parser,
                   bool inGenexpLambda)
 {
-    MOZ_ASSERT(node->isKind(PNK_DELETEELEM) || node->isKind(PNK_DELETESUPERELEM));
+    MOZ_ASSERT(node->isKind(PNK_DELETEELEM));
     MOZ_ASSERT(node->isArity(PN_UNARY));
-    MOZ_ASSERT(node->pn_kid->isKind(PNK_ELEM) || node->pn_kid->isKind(PNK_SUPERELEM));
+    MOZ_ASSERT(node->pn_kid->isKind(PNK_ELEM));
 
     ParseNode*& expr = node->pn_kid;
     if (!Fold(cx, &expr, parser, inGenexpLambda))
@@ -645,11 +643,9 @@ FoldDeleteElement(ExclusiveContext* cx, ParseNode* node, Parser<FullParseHandler
     //
     // In principle this also applies to |super["foo"] -> super.foo|,
     // but we don't constant-fold |super["foo"]| yet.
-    if (node->isKind(PNK_DELETEELEM)) {
-        MOZ_ASSERT(expr->isKind(PNK_ELEM) || expr->isKind(PNK_DOT));
-        if (expr->isKind(PNK_DOT))
-            node->setKind(PNK_DELETEPROP);
-    }
+    MOZ_ASSERT(expr->isKind(PNK_ELEM) || expr->isKind(PNK_DOT));
+    if (expr->isKind(PNK_DOT))
+        node->setKind(PNK_DELETEPROP);
 
     return true;
 }
@@ -1748,7 +1744,6 @@ Fold(ExclusiveContext* cx, ParseNode** pnp, Parser<FullParseHandler>& parser, bo
         return FoldDeleteExpr(cx, pn, parser, inGenexpLambda);
 
       case PNK_DELETEELEM:
-      case PNK_DELETESUPERELEM:
         return FoldDeleteElement(cx, pn, parser, inGenexpLambda);
 
       case PNK_DELETEPROP:
@@ -1779,7 +1774,6 @@ Fold(ExclusiveContext* cx, ParseNode** pnp, Parser<FullParseHandler>& parser, bo
       case PNK_MUTATEPROTO:
       case PNK_COMPUTED_NAME:
       case PNK_SPREAD:
-      case PNK_SUPERELEM:
       case PNK_EXPORT:
       case PNK_EXPORT_DEFAULT:
       case PNK_VOID:

js/src/frontend/FullParseHandler.h

@@ -73,9 +73,7 @@ class FullParseHandler
     typedef Definition* DefinitionNode;
 
     bool isPropertyAccess(ParseNode* node) {
-        if (node->isKind(PNK_DOT) || node->isKind(PNK_ELEM))
-            return true;
-        return node->isKind(PNK_SUPERELEM);
+        return node->isKind(PNK_DOT) || node->isKind(PNK_ELEM);
     }
 
     bool isFunctionCall(ParseNode* node) {
@@ -228,8 +226,6 @@ class FullParseHandler
 
         if (expr->isKind(PNK_ELEM))
             return newUnary(PNK_DELETEELEM, JSOP_NOP, begin, expr);
-        if (expr->isKind(PNK_SUPERELEM))
-            return newUnary(PNK_DELETESUPERELEM, JSOP_NOP, begin, expr);
 
         return newUnary(PNK_DELETEEXPR, JSOP_NOP, begin, expr);
     }
@@ -344,9 +340,6 @@ class FullParseHandler
     ParseNode* newClassNames(ParseNode* outer, ParseNode* inner, const TokenPos& pos) {
         return new_<ClassNames>(outer, inner, pos);
     }
-    ParseNode* newSuperElement(ParseNode* expr, const TokenPos& pos) {
-        return new_<SuperElement>(expr, pos);
-    }
     ParseNode* newNewTarget(ParseNode* newHolder, ParseNode* targetHolder) {
         return new_<BinaryNode>(PNK_NEWTARGET, JSOP_NOP, newHolder, targetHolder);
     }

js/src/frontend/NameFunctions.cpp

@@ -400,7 +400,6 @@ class NameResolver
           case PNK_DELETENAME:
           case PNK_DELETEPROP:
           case PNK_DELETEELEM:
-          case PNK_DELETESUPERELEM:
           case PNK_DELETEEXPR:
           case PNK_NEG:
           case PNK_POS:
@@ -412,7 +411,6 @@ class NameResolver
           case PNK_ARRAYPUSH:
           case PNK_SPREAD:
           case PNK_MUTATEPROTO:
-          case PNK_SUPERELEM:
           case PNK_EXPORT:
           case PNK_EXPORT_DEFAULT:
             MOZ_ASSERT(cur->isArity(PN_UNARY));
@@ -443,7 +441,6 @@ class NameResolver
           case PNK_DIVASSIGN:
           case PNK_MODASSIGN:
           case PNK_POWASSIGN:
-          case PNK_ELEM:
           case PNK_COLON:
           case PNK_CASE:
           case PNK_SHORTHAND:
@@ -460,6 +457,14 @@ class NameResolver
                 return false;
             break;
 
+          case PNK_ELEM:
+            MOZ_ASSERT(cur->isArity(PN_BINARY));
+            if (!cur->as<PropertyByValue>().isSuper() && !resolve(cur->pn_left, prefix))
+                return false;
+            if (!resolve(cur->pn_right, prefix))
+                return false;
+            break;
+
           case PNK_WITH:
             MOZ_ASSERT(cur->isArity(PN_BINARY_OBJ));
             if (!resolve(cur->pn_left, prefix))

js/src/frontend/ParseNode.cpp

@@ -230,7 +230,6 @@ PushNodeChildren(ParseNode* pn, NodeStack* stack)
       case PNK_DELETENAME:
       case PNK_DELETEPROP:
       case PNK_DELETEELEM:
-      case PNK_DELETESUPERELEM:
       case PNK_DELETEEXPR:
       case PNK_POS:
       case PNK_NEG:
@@ -244,7 +243,6 @@ PushNodeChildren(ParseNode* pn, NodeStack* stack)
       case PNK_MUTATEPROTO:
       case PNK_EXPORT:
       case PNK_EXPORT_DEFAULT:
-      case PNK_SUPERELEM:
         return PushUnaryNodeChild(pn, stack);
 
       // Nodes with a single nullable child.

js/src/frontend/ParseNode.h

@@ -139,7 +139,6 @@ class PackedScopeCoordinate
     F(DELETENAME) \
     F(DELETEPROP) \
     F(DELETEELEM) \
-    F(DELETESUPERELEM) \
     F(DELETEEXPR) \
     F(TRY) \
     F(CATCH) \
@@ -175,7 +174,6 @@ class PackedScopeCoordinate
     F(CLASSMETHOD) \
     F(CLASSMETHODLIST) \
     F(CLASSNAMES) \
-    F(SUPERELEM) \
     F(NEWTARGET) \
     F(POSHOLDER) \
     \
@@ -1337,6 +1335,17 @@ class PropertyByValue : public ParseNode
         pn_u.binary.left = lhs;
         pn_u.binary.right = propExpr;
     }
+
+    static bool test(const ParseNode& node) {
+        bool match = node.isKind(PNK_ELEM);
+        MOZ_ASSERT_IF(match, node.isArity(PN_BINARY));
+        return match;
+    }
+
+    bool isSuper() const {
+        // Like PropertyAccess above, PNK_POSHOLDER is "good enough".
+        return pn_left->isKind(PNK_POSHOLDER);
+    }
 };
 
 /*
@@ -1449,22 +1458,6 @@ struct ClassNode : public TernaryNode {
     }
 };
 
-struct SuperElement : public UnaryNode {
-    SuperElement(ParseNode* expr, const TokenPos& pos)
-      : UnaryNode(PNK_SUPERELEM, JSOP_NOP, pos, expr)
-    { }
-
-    static bool test(const ParseNode& node) {
-        bool match = node.isKind(PNK_SUPERELEM);
-        MOZ_ASSERT_IF(match, node.isArity(PN_UNARY));
-        return match;
-    }
-
-    ParseNode* expr() const {
-        return pn_kid;
-    }
-};
-
 #ifdef DEBUG
 void DumpParseTree(ParseNode* pn, int indent = 0);
 #endif

js/src/frontend/Parser.cpp

@@ -4966,7 +4966,6 @@ Parser<FullParseHandler>::isValidForStatementLHS(ParseNode* pn1, JSVersion versi
       case PNK_CALL:
       case PNK_DOT:
       case PNK_ELEM:
-      case PNK_SUPERELEM:
       case PNK_NAME:
       case PNK_OBJECT:
         return true;
@@ -8249,8 +8248,6 @@ Parser<ParseHandler>::memberExpr(YieldHandling yieldHandling, TokenKind tt, bool
 
     JS_CHECK_RECURSION(context, return null());
 
-    uint32_t superBegin = pos().begin;
-
     /* Check for new expression first. */
     if (tt == TOK_NEW) {
         uint32_t newBegin = pos().begin;
@@ -8326,15 +8323,11 @@ Parser<ParseHandler>::memberExpr(YieldHandling yieldHandling, TokenKind tt, bool
 
             MUST_MATCH_TOKEN(TOK_RB, JSMSG_BRACKET_IN_INDEX);
 
-            if (handler.isSuperBase(lhs, context)) {
-                if (!checkAndMarkSuperScope()) {
+            if (handler.isSuperBase(lhs, context) && !checkAndMarkSuperScope()) {
                     report(ParseError, false, null(), JSMSG_BAD_SUPERPROP, "member");
                     return null();
-                }
-                nextMember = handler.newSuperElement(propExpr, TokenPos(superBegin, pos().end));
-            } else {
-                nextMember = handler.newPropertyByValue(lhs, propExpr, pos().end);
             }
+            nextMember = handler.newPropertyByValue(lhs, propExpr, pos().end);
             if (!nextMember)
                 return null();
         } else if ((allowCallSyntax && tt == TOK_LP) ||

js/src/frontend/SyntaxParseHandler.h

@@ -47,8 +47,6 @@ class SyntaxParseHandler
         NodeThrow,
         NodeEmptyStatement,
 
-        NodeSuperElement,
-
         // This is needed for proper assignment-target handling.  ES6 formally
         // requires function calls *not* pass IsValidSimpleAssignmentTarget,
         // but at last check there were still sites with |f() = 5| and similar
@@ -140,8 +138,7 @@ class SyntaxParseHandler
     typedef Definition::Kind DefinitionNode;
 
     bool isPropertyAccess(Node node) {
-        return node == NodeDottedProperty || node == NodeElement ||
-               node == NodeSuperElement;
+        return node == NodeDottedProperty || node == NodeElement;
     }
 
     bool isFunctionCall(Node node) {
@@ -277,9 +274,6 @@ class SyntaxParseHandler
     Node newObjectLiteral(uint32_t begin) { return NodeUnparenthesizedObject; }
     Node newClassMethodList(uint32_t begin) { return NodeGeneric; }
 
-    Node newSuperElement(Node expr, const TokenPos& pos) {
-        return NodeSuperElement;
-    }
     Node newNewTarget(Node newHolder, Node targetHolder) { return NodeGeneric; }
     Node newPosHolder(const TokenPos& pos) { return NodeGeneric; }
     Node newSuperBase(const TokenPos& pos, ExclusiveContext* cx) { return NodeSuperBase; }

js/src/tests/ecma_6/Class/superPropDVG.js

@@ -7,11 +7,15 @@ class testNonExistent {
         super["prop"]();
     }
 }
-assertThrownErrorContains(() => new testNonExistent(), 'super["prop"]');
+// Should fold to super.prop
+assertThrownErrorContains(() => new testNonExistent(), 'super.prop');
 
 var ol = { testNonExistent() { super.prop(); } };
 assertThrownErrorContains(() => ol.testNonExistent(), "super.prop");
 
+var olElem = { testNonExistent() { var prop = "prop"; super[prop](); } };
+assertThrownErrorContains(() => olElem.testNonExistent(), "super[prop]");
+
 `;
 
 if (classesEnabled())