[proxies] use [[GetPrototypeOf]] trap in for-in

test/mjsunit/for-in-opt.js

Index: test/mjsunit/for-in-opt.js
diff --git a/test/mjsunit/for-in-opt.js b/test/mjsunit/for-in-opt.js
index 8f735393825446e52a91f9e8ec156c7ba3f04870..d486b6f0e92a316b899979f2a2e0e2c885a87c77 100644
--- a/test/mjsunit/for-in-opt.js
+++ b/test/mjsunit/for-in-opt.js
@@ -23,9 +23,9 @@ assertEquals(["0","1","2"], f("bla"));
 
 // Test the lazy deopt points.
 var keys = ["a", "b", "c", "d"];
-var has_keys = [];
-var deopt_has = false;
+var property_descriptor_keys = [];
 var deopt_enum = false;
+var deopt_property_descriptor = false;
 
 var handler = {
   ownKeys() {
@@ -35,16 +35,14 @@ var handler = {
     }
     return keys;
   },
-  getOwnPropertyDescriptor() { return { enumerable: true, configurable: true }},
-
-  has(target, k) {
-    if (deopt_has) {
+  getOwnPropertyDescriptor(target, k) {
+    if (deopt_property_descriptor) {
       %DeoptimizeFunction(f2);
-      deopt_has = false;
+      deopt_property_descriptor = false;
     }
-    has_keys.push(k);
-    return true;
-  }
+    property_descriptor_keys.push(k);
+    return { enumerable: true, configurable: true }
+  },
 };
 
 
@@ -61,8 +59,8 @@ function f2(o) {
 
 function check_f2() {
   assertEquals(keys, f2(o));
-  assertEquals(keys, has_keys);
-  has_keys.length = 0;
+  assertEquals(keys, property_descriptor_keys);
+  property_descriptor_keys.length = 0;
 }
 
 check_f2();
@@ -75,9 +73,10 @@ check_f2();
 
 // Test lazy deopt after FILTER_KEY
 %OptimizeFunctionOnNextCall(f2);
-deopt_has = true;
+deopt_property_descriptor = true;
 check_f2();
 
+
 function f3(o) {
   for (var i in o) {
   }
@@ -91,14 +90,6 @@ f3(undefined);
 f3(null);
 
 // Reliable repro for an issue previously flushed out by GC stress.
-var handler2 = {

[Jakob Kummerow, 2016/03/18 14:12:00]

That's weird. This careful setup of handler2/proxy2/o2 looks a lot like they
should be used somewhere. Maybe in the f4(o, p) call in line 114? But then the
expectations in check_f4 wouldn't make sense. Hmmm... Fine, drop it.

[Camillo Bruni, 2016/03/18 17:46:34]

yeah, this confused me more that it should have... 

-  getPropertyDescriptor(target, k) {
-    has_keys.push(k);
-    return {value: 10, configurable: true, writable: false, enumerable: true};
-  }
-}
-var proxy2 = new Proxy({}, handler2);
-var o2 = {__proto__: proxy2};
 var p = {x: "x"}
 
 function f4(o, p) {
@@ -112,8 +103,8 @@ function f4(o, p) {
 
 function check_f4() {
   assertEquals(keys, f4(o, p));
-  assertEquals(keys, has_keys);
-  has_keys.length = 0;
+  assertEquals(keys, property_descriptor_keys);
+  property_descriptor_keys.length = 0;
 }
 
 check_f4();
@@ -138,12 +129,10 @@ function listener(event, exec_state, event_data, data) {
 
 var handler3 = {
   ownKeys() { return ["a", "b"] },
-  getOwnPropertyDescriptor() { return { enumerable: true, configurable: true }},
-
-  has(target, k) {
+  getOwnPropertyDescriptor(target, k) {
     if (k == "a") count++;
-    if (x) %ScheduleBreak();
-    return true;
+    if (x) %ScheduleBreak()

[Jakob Kummerow, 2016/03/18 14:12:00]

nit: why drop the semicolons?

[Camillo Bruni, 2016/03/18 17:46:34]

random... will re-add ;)

+    return { enumerable: true, configurable: true }
   }
 };