G++'s statements as expressions feature

[address@hidden]

Consider the following code:

#include <iostream>

int main()
{
   std::cout << ({(void)123; "apple";}) << '\n'; // *
   std::cout << ({(void)123; (const char*)"apple";}) << '\n';
}

The line marked * gives the following compilation error:

cd d:/home/3-autogc-nosplit/
make 2008/tests/t-22-bug.run
* Compiling 2008/tests/t-22-bug.cc DEBUG
g++ -g -O0 -W -Wall -Wpointer-arith -Wformat -ffast-math -mwindows -c
2008/tests/t-22-bug.cc -o 2008/tests/t-22-bug.o
2008/tests/t-22-bug.cc: In function `int main()':
2008/tests/t-22-bug.cc:5: invalid use of non-lvalue array
make: *** [2008/tests/t-22-bug.o] Error 1

Compilation exited abnormally with code 2 at Sat Mar 01 15:47:53
Compilation took 1 second

My question is why does the compiler generate this error?  The line
that follows the bugged one compiles just fine.

My reason for asking this question is that I am writing a new
programming language that combines the best of C++ and Lisp and I will
be needing to use G++'s statements as expressions feature (as used
above).   To get around the above bug I will need to insert the cast
(const char*) to the front of every literal string.   I would very
much like to avoid having to do this.