harmony-scoping: make assignment to 'const' a late error.

src/x64/full-codegen-x64.cc

 // Copyright 2012 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_X64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 2578 matching lines @@
       DCHECK(var->IsStackAllocated() || var->IsContextSlot());
       MemOperand location = VarOperand(var, rcx);
       if (generate_debug_code_ && op == Token::INIT_LET) {
         // Check for an uninitialized let binding.
         __ movp(rdx, location);
         __ CompareRoot(rdx, Heap::kTheHoleValueRootIndex);
         __ Check(equal, kLetBindingReInitialization);
       }
       EmitStoreToStackLocalOrContextSlot(var, location);
     }
+  } else if (var->IsSignallingAssignmentToConst(op, strict_mode())) {
+    __ CallRuntime(Runtime::kThrowConstAssignError, 0);
   }
-  // Non-initializing assignments to consts are ignored.
 }
 
 
 void FullCodeGenerator::EmitNamedPropertyAssignment(Assignment* expr) {
   // Assignment to a property, using a named store IC.
   Property* prop = expr->target()->AsProperty();
   DCHECK(prop != NULL);
   DCHECK(prop->key()->IsLiteral());
 
   // Record source code position before IC call.
@@ skipping 2581 matching lines @@
   DCHECK_EQ(isolate->builtins()->OsrAfterStackCheck()->entry(),
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64