Always fail when trying to store to an undeclared global variable, even if it was found.

test/cctest/test-global-object.cc

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-// Flags: --allow-natives-syntax
+#include "v8.h"
 
-"use strict";
+#include "cctest.h"
 
-function f(a, b) {
-  return g("c", "d");
+using namespace v8;
+
+// This test fails if properties on the prototype of the global object appear
+// as declared globals.
+TEST(StrictUndeclaredGlobalVariable) {
+  HandleScope scope;
+  v8::Local<v8::String> var_name = v8_str("x");
+  LocalContext context;
+  v8::TryCatch try_catch;
+  v8::Local<v8::Script> script = v8_compile("\"use strict\"; x = 42;");
+  v8::Handle<v8::Object> proto = v8::Object::New();
+  v8::Handle<v8::Object> global =
+      context->Global()->GetPrototype().As<v8::Object>();
+  proto->Set(var_name, v8_num(100));
+  global->SetPrototype(proto);
+  script->Run();
+  CHECK(try_catch.HasCaught());
+  v8::String::Utf8Value exception(try_catch.Exception());
+  CHECK_EQ("ReferenceError: x is not defined", *exception);
 }
-
-function g(a, b) {
-  g.constructor.apply(this, arguments);
-}
-
-g.constructor = function(a, b) {
-  assertEquals("c", a);
-  assertEquals("d", b);
-}
-
-f("a", "b");
-f("a", "b");
-%OptimizeFunctionOnNextCall(f);
-f("a", "b");
-g.x = "deopt";
-f("a", "b");