[Bug c++/54946] New: ICE on template parameter from cast char-pointer in C++11 constexpr struct

[bisqwit at iki dot fi]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54946



             Bug #: 54946

           Summary: ICE on template parameter from cast char-pointer in

                    C++11 constexpr struct

    Classification: Unclassified

           Product: gcc

           Version: 4.7.1

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: c++

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: bisq...@iki.fi





The following C++11 code causes an ICE.



template<conts char*s>    static void testfunc();

constexpr struct testtype { const char* str; } test = { "abc"} ;

void (*functionpointer)() = testfunc<(const char*) test.str>;



Sample GCC commandline to invoke the error: g++ test1.cc -std=c++0x



Error message on g++-4.7.1 (Debian 4.7.1-7 on x86_64)

test1.cc:5:29: internal compiler error: in convert_nontype_argument, at

cp/pt.c:5794



Error message on g++-4.6.3 (Debian 4.6.3-11 on x86_64):

test1.cc:5:29: internal compiler error: in convert_nontype_argument, at

cp/pt.c:5430



I do not know whether the code is valid.

Things that do not affect the error:

- Adding / removing "const" at any point or changing pointers into arrays at

any point

- Changing functionpointer into an array of function pointers

- Any code generation related options (such as -m32 or optimization levels)



Things that do hide the error:

- Removing the (const char*) cast entirely

- Changing the string pointers into integers

- Removing the struct encapsulation from str (making it constexpr const char*

str = "abc"; and removing "test." from the third line)