[Boost-users] [xpressive] Shouldn't external placeholder variables allow consts?

I came across an interesting problem: what.let(_placeholder = this); fails to compile, because 'this' is a const pointer. A simple workaround: MyClass *_this = this; what.let(_placeholder = _this); But surely this shouldn't be necessary? Couldn't the right hand side of the let be declared const? Regards, Ami.