------- Comment #3 from jens dot maurer at gmx dot net 2006-11-14 20:24 ------- I agree with Wolfgang's interpretation of the standard, but can't see why it renders my original code invalid.
14.3.2/1 says that "a constant expression that evaluates to a null member pointer value" is allowed as a non-type template argument, with an explicit reference to 4.11, which explains how to obtain one (i.e. convert a null pointer constant, e.g. 0, to a pointer-to-member type). That's what my original example does. 14.3.2/5 then says "The following conversions are performed on each expression used as a non-type template-argument." There are indeed no conversions performed for pointer-to-members, but the expression I supplied for the non-type template-argument was "(void(C::*)(int))0", not just 0 (which would have required an implicit conversion, see 4.11). And no conversion is necessary to convert an expression of that type to the parameter's type, which is void(C::*)(int). (EDG appears to agree with me and accepts the code, FWIW.) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29704
