Issue 87: Allow unicode escapes in regexp flags.

src/scanner.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 366 matching lines @@
     int d = HexValue(c0_);
     if (d < 0) {
       // According to ECMA-262, 3rd, 7.8.4, page 18, these hex escapes
       // should be illegal, but other JS VMs just return the
       // non-escaped version of the original character.
 
       // Push back digits read, except the last one (in c0_).
       for (int j = i-1; j >= 0; j--) {
         PushBack(digits[j]);
       }
-
+      // Notice: No handling of error - treat it as "\u"->"u".
       return c;
     }
     x = x * 16 + d;
     Advance();
   }
 
   return x;
 }
 
 
@@ skipping 424 matching lines @@
   Advance();  // consume '/'
 
   TerminateLiteral();
 
   return true;
 }
 
 bool Scanner::ScanRegExpFlags() {
   // Scan regular expression flags.
   StartLiteral();
-  while (kIsIdentifierPart.get(c0_))
+  while (kIsIdentifierPart.get(c0_)) {
+    if (c0_ == '\\') {
+      uc32 c = ScanIdentifierUnicodeEscape();
+      if (c != static_cast<uc32>(unibrow::Utf8::kBadChar)) {
+        // We allow any escaped character, unlike the restriction on
+        // IdentifierPart when it is used to build an IdentifierName.
+        AddChar(c);
+        continue;
+      }
+    }
     AddCharAdvance();
+  }
   TerminateLiteral();
 
   next_.location.end_pos = source_pos() - 1;
   return true;
 }
 
 } }  // namespace v8::internal