Implement proper scoping for "this" in arrow functions

src/arm64/full-codegen-arm64.cc

 // Copyright 2013 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/v8.h"
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 106 matching lines @@
 #ifdef DEBUG
   if (strlen(FLAG_stop_at) > 0 &&
       info->function()->name()->IsUtf8EqualTo(CStrVector(FLAG_stop_at))) {
     __ Debug("stop-at", __LINE__, BREAK);
   }
 #endif
 
   // Sloppy mode functions and builtins need to replace the receiver with the
   // global proxy when called as functions (without an explicit receiver
   // object).
-  if (info->strict_mode() == SLOPPY && !info->is_native()) {
+  if (info->strict_mode() == SLOPPY && !info->is_native() &&
+      info->scope()->has_this_declaration()) {
     Label ok;
     int receiver_offset = info->scope()->num_parameters() * kXRegSize;
     __ Peek(x10, receiver_offset);
     __ JumpIfNotRoot(x10, Heap::kUndefinedValueRootIndex, &ok);
 
     __ Ldr(x10, GlobalObjectMemOperand());
     __ Ldr(x10, FieldMemOperand(x10, GlobalObject::kGlobalProxyOffset));
     __ Poke(x10, receiver_offset);
 
     __ Bind(&ok);
@@ skipping 71 matching lines @@
       __ Push(x1);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
     function_in_register_x1 = false;
     // Context is returned in x0.  It replaces the context passed to us.
     // It's saved in the stack and kept live in cp.
     __ Mov(cp, x0);
     __ Str(x0, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = info->scope()->num_parameters();
-    for (int i = 0; i < num_parameters; i++) {
-      Variable* var = scope()->parameter(i);
+    int first_parameter = info->scope()->has_this_declaration() ? -1 : 0;
+    for (int i = first_parameter; i < num_parameters; i++) {
+      Variable* var = (i == -1) ? scope()->receiver() : scope()->parameter(i);
       if (var->IsContextSlot()) {
         int parameter_offset = StandardFrameConstants::kCallerSPOffset +
             (num_parameters - 1 - i) * kPointerSize;
         // Load parameter from stack.
         __ Ldr(x10, MemOperand(fp, parameter_offset));
         // Store it in the context.
         MemOperand target = ContextMemOperand(cp, var->index());
         __ Str(x10, target);
 
         // Update the write barrier.
@@ skipping 5154 matching lines @@
   return previous_;
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64