Since C++11 and until C++17, the range-for loop is equivalent to the following code:
{
auto && __range = range_expression ;
for (auto __begin = begin_expr, __end = end_expr; __begin != __end; ++__begin) {
range_declaration = *__begin;
loop_statement
}
}
Starting from C++17 the equivalence will be (apparently) updated to this one:
{
auto && __range = range_expression ;
auto __begin = begin_expr ;
auto __end = end_expr ;
for ( ; __begin != __end; ++__begin) {
range_declaration = *__begin;
loop_statement
}
}
At a first glance the only difference I can see is in the fact that __begin and __end have no longer to share the type, as long as they are (let me say) comparable.
Is there any other reason for which this kind of change is required?
