[Bug c++/65880] New: Member function issue with argument "pointer to const array of member function pointers"

[habanero_pizza at yahoo dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65880

            Bug ID: 65880
           Summary: Member function issue with argument "pointer to const
                    array of member function pointers"
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: habanero_pizza at yahoo dot com
                CC: habanero_pizza at yahoo dot com
              Host: i686-pc-linux-gnu
            Target: i686-pc-linux-gnu
             Build: i686-pc-linux-gnu

Created attachment 35396
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35396&action=edit
Test case source:  fails if OKAY is not defined...

When a member function takes an argument of the form:

  type (classname::* const *ptr)(void)

AND the implementation of the function appears BEFORE its reference by another
member function, the compiler believes (at reference time) that the argument
type should be:

  type (classname::* *ptr)(void)

That is, the "const" seems to get dropped from the declaration.  However, if
the implementation of the function appears AFTER references by other member
functions, the code compiles correctly.

This seems to be a new issue with gcc 5.1.0, as 4.9.2 compiles the problem case
properly.

Example run demonstrating the problem:

$ i386-eabi-g++ -v -save-temps -o test-const-mfp-table-arg
test-const-mfp-table-arg.cc
Using built-in specs.
COLLECT_GCC=i386-eabi-g++
COLLECT_LTO_WRAPPER=/usr/local/i386-eabi-5.1.0/libexec/gcc/i686-pc-linux-gnu/5.1
.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../../gcc-5.1.0/configure --prefix=/usr/local/i386-eabi-5.1.0
-
-program-prefix=i386-eabi- --enable-languages=c,c++
--with-gmp=/usr/local/i386-e
abi-5.1.0 --with-mpfr=/usr/local/i386-eabi-5.1.0
--with-mpc=/usr/local/i386-eabi
-5.1.0 --with-isl=/usr/local/i386-eabi-5.1.0 --with-zlib=/usr/local
--enable-lto
 --enable-gold
Thread model: posix
gcc version 5.1.0 (GCC) 
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-o' 'test-const-mfp-table-arg'
'-shared-
libgcc' '-mtune=generic' '-march=pentiumpro'
 /usr/local/i386-eabi-5.1.0/libexec/gcc/i686-pc-linux-gnu/5.1.0/cc1plus -E
-quie
t -v -D_GNU_SOURCE test-const-mfp-table-arg.cc -mtune=generic -march=pentiumpro 
-fpch-preprocess -o test-const-mfp-table-arg.ii
ignoring nonexistent directory
"/usr/local/i386-eabi-5.1.0/lib/gcc/i686-pc-linux
-gnu/5.1.0/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/usr/local/i386-eabi-5.1.0/lib/gcc/i686-pc-linux-gnu/5.1.0/../../../../include/
c++/5.1.0

/usr/local/i386-eabi-5.1.0/lib/gcc/i686-pc-linux-gnu/5.1.0/../../../../include/
c++/5.1.0/i686-pc-linux-gnu

/usr/local/i386-eabi-5.1.0/lib/gcc/i686-pc-linux-gnu/5.1.0/../../../../include/
c++/5.1.0/backward
 /usr/local/i386-eabi-5.1.0/lib/gcc/i686-pc-linux-gnu/5.1.0/include
 /usr/local/include
 /usr/local/i386-eabi-5.1.0/include
 /usr/local/i386-eabi-5.1.0/lib/gcc/i686-pc-linux-gnu/5.1.0/include-fixed
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-o' 'test-const-mfp-table-arg'
'-shared-
libgcc' '-mtune=generic' '-march=pentiumpro'
 /usr/local/i386-eabi-5.1.0/libexec/gcc/i686-pc-linux-gnu/5.1.0/cc1plus
-fprepro
cessed test-const-mfp-table-arg.ii -quiet -dumpbase test-const-mfp-table-arg.cc 
-mtune=generic -march=pentiumpro -auxbase test-const-mfp-table-arg -version -o
t
est-const-mfp-table-arg.s
GNU C++ (GCC) version 5.1.0 (i686-pc-linux-gnu)
        compiled by GNU C version 5.1.0, GMP version 5.1.3, MPFR version 3.1.2, 
MPC version 1.0.3
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++ (GCC) version 5.1.0 (i686-pc-linux-gnu)
        compiled by GNU C version 5.1.0, GMP version 5.1.3, MPFR version 3.1.2, 
MPC version 1.0.3
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 8a9e49c211f4d1d2fc149d62c24d84d4
test-const-mfp-table-arg.cc: In member function ‘bool Test::barl()’:
test-const-mfp-table-arg.cc:67:20: error: invalid conversion from ‘bool
(Test::*
 const*)()’ to ‘bool (Test::**)()’ [-fpermissive]
     return fool(fms);
                    ^
test-const-mfp-table-arg.cc:40:6: note:   initializing argument 1 of ‘bool
Test:
:fool(bool (Test::**)())’
 bool Test::fool(bool (Test::* const *fms)(void))
      ^

Preprocessor output (test-const-mfp-table-arg.ii):

# 1 "test-const-mfp-table-arg.cc"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "test-const-mfp-table-arg.cc"


class Test
{
  public:
    Test();
    ~Test();

    bool barl(void);

  private:
    bool fool(bool (Test::* const *fms)(void));
    bool foo(void);
    bool bar(void);
};

Test::Test()
{
}

Test::~Test()
{
}
# 40 "test-const-mfp-table-arg.cc"
bool Test::fool(bool (Test::* const *fms)(void))
{
    bool retval = false;

    int i = 0;
    bool (Test::*f)(void) = fms[i++];

    while (f) {
        retval = (this->*f)();
        if (retval) break;
        f = fms[i++];
    }

    return retval;
}


bool Test::barl(void)
{
    static bool (Test::* const fms[])(void) = {
        &Test::foo,
        &Test::bar,
        0
    };



    return fool(fms);
}


bool Test::foo(void)
{
    return false;
}

bool Test::bar(void)
{
    return true;
}

int main(int argc, const char *argv[])
{
    Test t;
    return t.barl();
}