Native try-catch syntax parsing should not crash.

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 "src/api.h"
 #include "src/ast/ast.h"
 #include "src/ast/ast-expression-rewriter.h"
 #include "src/ast/ast-expression-visitor.h"
@@ skipping 2975 matching lines @@
   int pos = position();
 
   Block* try_block;
   {
     ReturnExprScope no_tail_calls(function_state_,
                                   ReturnExprContext::kInsideTryBlock);
     try_block = ParseBlock(NULL, CHECK_OK);
   }
 
   Token::Value tok = peek();
+
   bool catch_for_promise_reject = false;
+  if (allow_natives() && tok == Token::MOD) {
+    Consume(Token::MOD);
+    catch_for_promise_reject = true;
+    tok = peek();
+  }
+
   if (tok != Token::CATCH && tok != Token::FINALLY) {
-    if (allow_natives() && tok == Token::MOD) {
-      Consume(Token::MOD);
-      catch_for_promise_reject = true;
-      tok = peek();
-      DCHECK_EQ(Token::CATCH, tok);
-    } else {
-      ReportMessage(MessageTemplate::kNoCatchOrFinally);
-      *ok = false;
-      return NULL;
-    }
+    ReportMessage(MessageTemplate::kNoCatchOrFinally);
+    *ok = false;
+    return NULL;
   }
 
   Scope* catch_scope = NULL;
   Variable* catch_variable = NULL;
   Block* catch_block = NULL;
   TailCallExpressionList tail_call_expressions_in_catch_block(zone());
   if (tok == Token::CATCH) {
     Consume(Token::CATCH);
 
     Expect(Token::LPAREN, CHECK_OK);
@@ skipping 4069 matching lines @@
   node->Print(Isolate::Current());
 }
 #endif  // DEBUG
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8