Implement proper scoping for "this" in arrow functions

src/compiler/ast-graph-builder.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/ast-graph-builder.h"
 
+#include "src/ast-this-access-visitor.h"
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/operator-properties.h"
 #include "src/full-codegen.h"
 #include "src/parser.h"
@@ skipping 57 matching lines @@
     // It will be replaced with {Dead} after typing and optimizations.
     NewNode(common()->OsrNormalEntry());
   }
 
   // Initialize the incoming context.
   Node* outer_context = GetFunctionContext();
   set_current_context(outer_context);
 
   // Build receiver check for sloppy mode if necessary.
   // TODO(mstarzinger/verwaest): Should this be moved back into the CallIC?
-  Node* original_receiver = env.Lookup(scope->receiver());
-  Node* patched_receiver = BuildPatchReceiverToGlobalProxy(original_receiver);
-  env.Bind(scope->receiver(), patched_receiver);
+  if (scope->has_this_declaration()) {
+    Node* original_receiver = env.Lookup(scope->receiver());
+    Node* patched_receiver = BuildPatchReceiverToGlobalProxy(original_receiver);
+    env.Bind(scope->receiver(), patched_receiver);
+  }
 
   // Build node to initialize local function context.
   Node* closure = GetFunctionClosure();
   Node* inner_context = BuildLocalFunctionContext(outer_context, closure);
 
   // Push top-level function scope for the function body.
   ContextScope top_context(this, scope, inner_context);
 
   // Build the arguments object if it is used.
   BuildArgumentsObject(scope->arguments());
@@ skipping 1846 matching lines @@
 
 Node* AstGraphBuilder::BuildPatchReceiverToGlobalProxy(Node* receiver) {
   // Sloppy mode functions and builtins need to replace the receiver with the
   // global proxy when called as functions (without an explicit receiver
   // object). Otherwise there is nothing left to do here.
   if (info()->strict_mode() != SLOPPY || info()->is_native()) return receiver;
 
   // There is no need to perform patching if the receiver is never used. Note
   // that scope predicates are purely syntactical, a call to eval might still
   // inspect the receiver value.
-  if (!info()->scope()->uses_this() && !info()->scope()->inner_uses_this() &&
+
+  AstThisAccessVisitor this_access_visitor(isolate(), zone());
+  this_access_visitor.VisitStatements(info()->function()->body());
+
+  if (!this_access_visitor.UsesThis() &&
       !info()->scope()->calls_sloppy_eval()) {
     return receiver;
   }
 
   IfBuilder receiver_check(this);
   Node* undefined = jsgraph()->UndefinedConstant();
   Node* check = NewNode(javascript()->StrictEqual(), receiver, undefined);
   receiver_check.If(check);
   receiver_check.Then();
   environment()->Push(BuildLoadGlobalProxy());
@@ skipping 471 matching lines @@
 
 BitVector* AstGraphBuilder::GetVariablesAssignedInLoop(
     IterationStatement* stmt) {
   if (loop_assignment_analysis_ == NULL) return NULL;
   return loop_assignment_analysis_->GetVariablesAssignedInLoop(stmt);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8