[Bug c++/45080] New: [C++0x] Rejects lambda to function pointer conversion inside function template

[piotr dot rak at gmail dot com]

cat lambda-convX.C 

// { dg-options -std=c++0x }

typedef void(*pfn)();

template<int = 0>
   void f1 ()
   {
      pfn fn = []{};
   }

template<typename = int>
   void f2()
   {
      pfn fn = []{};
   }

void test()
{
    f1<>();
    f2<>();
}
[p...@a tmp] g++-trunk -v lambda-convX.C -c -std=c++0x
Using built-in specs.
COLLECT_GCC=/home/prak/Dev/gcc-install/bin/g++-trunk
COLLECT_LTO_WRAPPER=/home/prak/Dev/gcc-install/libexec/gcc/i686-pc-linux-gnu/4.6.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../gcc.git/configure --enable-languages=c,c++
--program-suffix=-trunk --prefix=/home/prak/Dev/gcc-install --disable-bootstrap
: (reconfigured) ../gcc.git/configure --enable-languages=c,c++
--program-suffix=-trunk --prefix=/home/prak/Dev/gcc-install --disable-bootstrap
: (reconfigured) ../gcc.git/configure --program-suffix=-trunk
--prefix=/home/prak/Dev/gcc-install --disable-bootstrap
--enable-languages=c,c++,lto --no-create --no-recursion
Thread model: posix
gcc version 4.6.0 20100725 (experimental) (GCC) 
COLLECT_GCC_OPTIONS='-v' '-c' '-std=c++0x' '-shared-libgcc' '-mtune=generic'
'-march=pentiumpro'
 /home/prak/Dev/gcc-install/libexec/gcc/i686-pc-linux-gnu/4.6.0/cc1plus -quiet
-v -D_GNU_SOURCE lambda-convX.C -quiet -dumpbase lambda-convX.C -mtune=generic
-march=pentiumpro -auxbase lambda-convX -std=c++0x -version -o /tmp/ccwd0zJD.s
GNU C++ (GCC) version 4.6.0 20100725 (experimental) (i686-pc-linux-gnu)
        compiled by GNU C version 4.4.4, GMP version 4.3.2, MPFR version 3.0.0,
MPC version 0.8.2
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory
"/home/prak/Dev/gcc-install/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/home/prak/Dev/gcc-install/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0

/home/prak/Dev/gcc-install/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/i686-pc-linux-gnu

/home/prak/Dev/gcc-install/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/backward
 /home/prak/Dev/gcc-install/include
 /home/prak/Dev/gcc-install/lib/gcc/i686-pc-linux-gnu/4.6.0/include
 /home/prak/Dev/gcc-install/lib/gcc/i686-pc-linux-gnu/4.6.0/include-fixed
 /usr/include
End of search list.
GNU C++ (GCC) version 4.6.0 20100725 (experimental) (i686-pc-linux-gnu)
        compiled by GNU C version 4.4.4, GMP version 4.3.2, MPFR version 3.0.0,
MPC version 0.8.2
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: 4866727cef69d58d8539d96f2ebb2a27
lambda-convX.C: In function ‘void f1() [with int <anonymous> = 0]’:
lambda-convX.C:20:10:   instantiated from here
lambda-convX.C:9:19: error: cannot convert ‘f1() [with int <anonymous> =
0]::<lambda()>’ to ‘pfn’ in initialization
lambda-convX.C: In function ‘void f2() [with <template-parameter-1-1> =
int]’:
lambda-convX.C:21:10:   instantiated from here
lambda-convX.C:15:19: error: cannot convert ‘f2() [with
<template-parameter-1-1> = int]::<lambda()>’ to ‘pfn’ in initialization


-- 
           Summary: [C++0x] Rejects lambda to function pointer conversion
                    inside function template
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: piotr dot rak at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45080