Re: [Boost-users] error using lambdas: conversion from 'x' tonon-scalar type 'y'

klaus triendl wrote: [...]

MyStream& operator <<(MyStream& os, const int&) { return os; }

int main() { list cont; MyStream osTop; MySubStream osSub(&osTop);

MyStream& tmp = osSub;

for_each(cont.begin(), cont.end(), ref(osSub) << *_1);

for_each( cont.begin(), cont.end(), tmp << *_1 ); // or, if the above doesn't work - it should - for_each( cont.begin(), cont.end(), ref(tmp) << *_1 );

return 0; } ----

g++ outputs error: '/usr/include/boost/lambda/detail/operator_lambda_func_base.hpp:212: error: conversion from 'MyStream' to non-scalar type 'MySubStream' requested'.

Lambda sees that you are invoking operator<< on a MySubStream& and deduces the return type to be MySubStream&; it isn't smart enough to see that you're actually using the operator<< definition for the base class MyStream.