[boost] [utility] value_initialized fix causes Intel-linux 9.0 compile error

Subject: [boost] [utility] value_initialized fix causes Intel-linux 9.0 compile error
From: Niels Dekker - mail address until 2010-10-10 (niels_address_until_2010-10-10_at_[hidden])
Date: 2009-02-24 14:41:40

My fix of the "const incorrectness" of boost::value_initialized 
(changeset [51355]), committed to the trunk last Friday, has passed the 
value_init_test tests successfully on most compilers, including 
intel-linux 10.0 and 10.1: 
www.boost.org/development/tests/trunk/developer/utility_.html 
Unfortunately it has a compile time regression failure on intel-linux 
9.0, when trying to compare a value_initialized<NonPOD*> and a NonPOD*:

  error: more than one operator "==" matches these operands:
  built-in operator "pointer == pointer"
  built-in operator "pointer == pointer"
  operand types are: boost::value_initialized<NonPOD *> == NonPOD *const

www.boost.org/development/tests/trunk/output/Sandia-intel-9-0-boost-bin-v2-libs-utility-test-value_init_test-test-intel-linux-9-0-debug.html

I don't have access to an Intel compiler, but it looks like the compile 
error is specific to pointers, as it doesn't seem to occur when 
comparing value_initialized<T> and T for other types T (int, double, 
POD, NonPOD).  Is this a known compiler bug of the Intel 9.0? 
Apparently it's fixed by Intel 10.0.

The fix of changeset [51355] replaced the existing conversion operator 
by a pair of them, overloaded for const and non-const. See also 
https://svn.boost.org/trac/boost/ticket/2548

Would it be okay to just mark the regression failure as "expected", and 
leave the implementation of boost::value_initialized as it is, including 
the const-fix?  Otherwise, do you have any suggestion for a workaround?

Note that the compile error is specific to the implicit use of the 
conversion operator.  value_initialized also provides "get" functions 
and data() member functions to retrieve its value, which should still 
work fine on Intel 9.0.

Kind regards, Niels

--
Niels Dekker
http://www.xs4all.nl/~nd/dekkerware
Scientific programmer at LKEB, Leiden University Medical Center