A decimal integer literal with a leading 0 is now an error in strict mode.

src/parsing/parser.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/parsing/parser.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/ast/ast-expression-rewriter.h"
@@ skipping 773 matching lines @@
       this->scope()->SetLanguageMode(info->language_mode());
       ParseStatementList(body, Token::EOS, &ok);
     }
 
     // The parser will peek but not consume EOS.  Our scope logically goes all
     // the way to the EOS, though.
     scope->set_end_position(scanner()->peek_location().beg_pos);
 
     if (ok && is_strict(language_mode())) {
       CheckStrictOctalLiteral(beg_pos, scanner()->location().end_pos, &ok);
-      CheckDecimalLiteralWithLeadingZero(beg_pos,
-                                         scanner()->location().end_pos);
     }
     if (ok && is_sloppy(language_mode())) {
       // TODO(littledan): Function bindings on the global object that modify
       // pre-existing bindings should be made writable, enumerable and
       // nonconfigurable if possible, whereas this code will leave attributes
       // unchanged if the property already exists.
       InsertSloppyBlockFunctionVarBindings(scope);
     }
     if (ok) {
       CheckConflictingVarDeclarations(scope, &ok);
@@ skipping 1896 matching lines @@
 
     // Validate function name. We can do this only after parsing the function,
     // since the function can declare itself strict.
     language_mode = scope->language_mode();
     CheckFunctionName(language_mode, function_name, function_name_validity,
                       function_name_location, CHECK_OK);
 
     if (is_strict(language_mode)) {
       CheckStrictOctalLiteral(scope->start_position(), scope->end_position(),
                               CHECK_OK);
-      CheckDecimalLiteralWithLeadingZero(scope->start_position(),
-                                         scope->end_position());
     }
     CheckConflictingVarDeclarations(scope, CHECK_OK);
   }  // DiscardableZoneScope goes out of scope.
 
   FunctionLiteral::ParameterFlag duplicate_parameters =
       has_duplicate_parameters ? FunctionLiteral::kHasDuplicateParameters
                                : FunctionLiteral::kNoDuplicateParameters;
 
   // Note that the FunctionLiteral needs to be created in the main Zone again.
   FunctionLiteral* function_literal = factory()->NewFunctionLiteral(
@@ skipping 2697 matching lines @@
 
   return final_loop;
 }
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8