id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
7900	karma indirect_iterator returns reference to temporary	Louis Dionne <louis.dionne92@…>	Hartmut Kaiser	"Hello,

The indirect_iterator in boost/spirit/home/karma/detail/indirect_iterator.hpp
returns a reference to a temporary in at least one corner case. The compiler
will issue a warning, but it's still UB.

I attached the minimal code to reproduce the behavior as well as a fix.
Without the fix, it will print crap and issue a warning (on Clang and GCC).

What happens:
I create a transformed_range, which uses a transform_iterator under the hood.
Since the function performing the transformation returns by value, the
the iterator_traits<transform_iterator>::reference type is NOT the same as
iterator_traits<transform_iterator>::value_type const&, hence the return of a
reference to a temporary.

My setup:
    gcc version 4.7.2
    clang version 3.2
    boost-trunk@82516

Best,

Louis Dionne
"	Patches	closed	To Be Determined	spirit	Boost Release Branch	Problem	fixed	karma indirect_iterator