Hi, all, DeprecatedChar::lower() method contain the following statement: return c <= 0x7F ? tolower(c) : u_tolower(c); 'c' is a private field of DeprecatedChar of type unsigned short, return type of the method is DeprecatedChar. The problem here is that u_tolower(c) return type is UChar32 which is 32bit on Windows platform, so conversion from UChar32 to DeprecatedChar is not trivial. The corresponding compiler error is: In file included from ../../../WebCore/dom/Node.h:29, from ../../../WebCore/dom/EventTargetNode.h:28, from ../../../WebCore/dom/ContainerNode.h:29, from ../../../WebCore/dom/Attr.h:28, from ../../../WebCore/bindings/js/JSAttrCustom.cpp:32: ../../../WebCore/platform/DeprecatedString.h: In member function `WebCore::DeprecatedChar WebCore::DeprecatedChar::lower() const': ../../../WebCore/platform/DeprecatedString.h:136: error: conversion from `long int' to `WebCore::DeprecatedChar' is ambiguous ../../../WebCore/platform/DeprecatedString.h:108: note: candidates are: WebCore::DeprecatedChar::DeprecatedChar(unsigned int) ../../../WebCore/platform/DeprecatedString.h:112: note: WebCore::DeprecatedChar::DeprecatedChar(int) ../../../WebCore/platform/DeprecatedString.h:104: note: WebCore::DeprecatedChar::DeprecatedChar(short unsigned int) ../../../WebCore/platform/DeprecatedString.h:100: note: WebCore::DeprecatedChar::DeprecatedChar(short int) ../../../WebCore/platform/DeprecatedString.h:96: note: WebCore::DeprecatedChar::DeprecatedChar(unsigned char) ../../../WebCore/platform/DeprecatedString.h:92: note: WebCore::DeprecatedChar::DeprecatedChar(char) - The same problem is with DeprecatedChar::upper() method. Is it a bug in WebKit code? Should an explicit cast be added to the methods? Thanks, Artem