[proxies] Improve JSProxyVerify and test most proxy invariants.

src/objects-debug.cc

Index: src/objects-debug.cc
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index e7ee7eca7731c3fe9593055f4fc2906b7ec1dfd5..a33e61de4c87e46d26dd7e5077e46a912e92e660 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -818,8 +818,22 @@ void JSRegExp::JSRegExpVerify() {
 
 void JSProxy::JSProxyVerify() {
   CHECK(IsJSProxy());
+  VerifyPointer(target());
   VerifyPointer(handler());
+  if (target()->IsCallable()) {

[Igor Sheludko, 2015/12/23 17:04:52]

You could probably rewrite these ifs like this:
  CHECK_EQ(target()->IsCallable(), map()->is_callable());
  CHECK_EQ(target()->IsConstructor(), map()->is_constructor());

[Camillo Bruni, 2015/12/23 19:07:01]

Sometimes I really wonder how I got so far with programming :D

+    CHECK(map()->is_callable());
+    if (target()->IsConstructor()) {
+      CHECK(map()->is_constructor());
+    } else {
+      CHECK(!map()->is_constructor());
+    }
+  } else {
+    CHECK(!map()->is_callable());
+  }
   CHECK(hash()->IsSmi() || hash()->IsUndefined());
+  CHECK(map()->prototype()->IsNull());
+  // There should be not properties on a Proxy.

[Igor Sheludko, 2015/12/23 17:04:52]

s/not/no/

+  CHECK_EQ(0, map()->NumberOfOwnDescriptors());
 }