Update identifier syntax to disallow U+2E2F

src/char-predicates.h

 // Copyright 2011 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.
 
 #ifndef V8_CHAR_PREDICATES_H_
 #define V8_CHAR_PREDICATES_H_
 
 #include "src/unicode.h"
 
 namespace v8 {
 namespace internal {
 
 // Unicode character predicates as defined by ECMA-262, 3rd,
 // used for lexical analysis.
 
 inline bool IsCarriageReturn(uc32 c);
 inline bool IsLineFeed(uc32 c);
 inline bool IsDecimalDigit(uc32 c);
 inline bool IsHexDigit(uc32 c);
 inline bool IsOctalDigit(uc32 c);
 inline bool IsBinaryDigit(uc32 c);
 inline bool IsRegExpWord(uc32 c);
 inline bool IsRegExpNewline(uc32 c);
 
 struct IdentifierStart {
   static inline bool Is(uc32 c) {
     switch (c) {
       case '$': case '_': case '\\': return true;
+      case 0x2e2f:
+        return false;  // U+2E2F is Vertical tilde.
       default: return unibrow::Letter::Is(c);
     }
   }
 };
 
 
 struct IdentifierPart {
   static inline bool Is(uc32 c) {
+    if (c == 0x2e2f) return false;  // U+2E2F is Vertical tilde.
     return IdentifierStart::Is(c)
         || unibrow::Number::Is(c)
         || c == 0x200C  // U+200C is Zero-Width Non-Joiner.
         || c == 0x200D  // U+200D is Zero-Width Joiner.
         || unibrow::CombiningMark::Is(c)
         || unibrow::ConnectorPunctuation::Is(c);
   }
 };
 
 
@@ skipping 13 matching lines @@
 // WhiteSpace and LineTerminator according to ECMA-262 5.1, 7.2 and 7.3.
 struct WhiteSpaceOrLineTerminator {
   static inline bool Is(uc32 c) {
     return WhiteSpace::Is(c) || unibrow::LineTerminator::Is(c);
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CHAR_PREDICATES_H_