The GCC 4.0.0 release does not support the use of the GNU builtin __complex__
anymore in, e.g., std::vector. The code below used to compile on GNU
(compatible) compilers prior to GCC 4.0

<code>
#include <vector>
typedef float __complex__ fcomplex;
std::vector<fcomplex> vfc(10);
</code>

GCC 4.0.0 produces the following diagnostic:

$ /data/loose/gcc-4.0.0/bin/g++ -v -save-temps -c -Wall -W tVec.cc

Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../../src/gcc-4.0.0/configure --prefix=/data/loose/gcc-4.0.0
--enable-threads --enable-__cxa_atexit
Thread model: posix
gcc version 4.0.0
 /data/loose/gcc-4.0.0/libexec/gcc/i686-pc-linux-gnu/4.0.0/cc1plus -E -quiet -v
-D_GNU_SOURCE tVec.cc -mtune=pentiumpro -Wall -W -fpch-preprocess -o tVec.ii
ignoring nonexistent directory
"/data/loose/gcc-4.0.0/lib/gcc/i686-pc-linux-gnu/4.0.0/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /data/loose/gcc-4.0.0/lib/gcc/i686-pc-linux-gnu/4.0.0/../../../../include/c++/4.0.0
 /data/loose/gcc-4.0.0/lib/gcc/i686-pc-linux-gnu/4.0.0/../../../../include/c++/4.0.0/i686-pc-linux-gnu
 /data/loose/gcc-4.0.0/lib/gcc/i686-pc-linux-gnu/4.0.0/../../../../include/c++/4.0.0/backward
 /usr/local/include
 /data/loose/gcc-4.0.0/include
 /data/loose/gcc-4.0.0/lib/gcc/i686-pc-linux-gnu/4.0.0/include
 /usr/include
End of search list.
 /data/loose/gcc-4.0.0/libexec/gcc/i686-pc-linux-gnu/4.0.0/cc1plus
-fpreprocessed tVec.ii -quiet -dumpbase tVec.cc -mtune=pentiumpro -auxbase tVec
-Wall -W -version -o tVec.s
GNU C++ version 4.0.0 (i686-pc-linux-gnu)
        compiled by GNU C version 4.0.0.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
/data/loose/gcc-4.0.0/lib/gcc/i686-pc-linux-gnu/4.0.0/../../../../include/c++/4.0.0/bits/stl_vector.h:
In constructor ‘std::vector<_Tp, _Alloc>::vector(size_t) [with _Tp = float
__complex__, _Alloc = std::allocator<float __complex__>]’:
tVec.cc:3:   instantiated from here
/data/loose/gcc-4.0.0/lib/gcc/i686-pc-linux-gnu/4.0.0/../../../../include/c++/4.0.0/bits/stl_vector.h:219:
error: invalid cast from type ‘int’ to type ‘float __complex__’

-- 
           Summary: STL containers do not accept GNU builtin __complex__
                    type anymore
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: loose at astron dot nl
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21210