thanks dicebot, jacob, rainer. now i understand better what is going on and why.
however, i don't see the issue fully resolved. in enum IDENTIFIER; IDENTIFIER is an identifier, there is no way around it. the enum declaration makes it a type too, but it continues to be an identifier. an identifier is a "PrimaryExpression". a "PrimaryExpression" is an "Expression", any expression is officially allowed in typeof. but it throws an error because this expression is a type too. same goes with alias IDENTIFIER2 = int; i don't think it can/should be fixed for identifiers only but instead typeof() should cover types in general: typeof(IDENTIFIER) = IDENTIFIER typeof(IDENTIFIER2 ) = int typeof(int) = int i see only advantages in this and it would clean up meta code from handling corner cases. (at least in my case, but being still on the newbie side of D programming i might not do it right.) /det