[Bug libstdc++/65928] New: std::find_if compilation errors

[david.claessens at tomra dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65928

            Bug ID: 65928
           Summary: std::find_if compilation errors
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: david.claessens at tomra dot com
  Target Milestone: ---

Created attachment 35421
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35421&action=edit
preprocessed file

COLLECT_GCC=g++-5
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/5/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
5.1.0-0ubuntu11~14.04.1' --with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-5 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=c++98 --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib
--with-tune=generic --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 5.1.0 (Ubuntu 5.1.0-0ubuntu11~14.04.1)


The code below compiles fine under 4.9.2 but gives errors under 5.1.0

compiler command: g++-5 -std=c++1y bug.cpp

adding -Wall -Wextra does not change the output for v5.1.0 but gives
unused-but-set-variable warnings on v4.9.2


#include <string>
#include <cctype>
#include <algorithm>

int main(int, char **)
{
    const std::string test_string("this is a test");

    auto first_space = std::find_if(
            std::begin(test_string),
            std::end(test_string),
            std::isblank);

    int (*myblank)(int) = &std::isblank;

    auto _space = std::find_if(
            std::begin(test_string),
            std::end(test_string),
            myblank);

    return 0;
}

The compiler output:
bug.cpp: In function ‘int main(int, char**)’:
bug.cpp:13:25: error: no matching function for call to
‘find_if(std::basic_string<char>::const_iterator,
std::basic_string<char>::const_iterator, <unresolved overloaded function
type>)’
             std::isblank);
                         ^
In file included from /usr/include/c++/5/algorithm:62:0,
                 from bug.cpp:4:
/usr/include/c++/5/bits/stl_algo.h:3806:5: note: candidate: template<class
_IIter, class _Predicate> _IIter std::find_if(_IIter, _IIter, _Predicate)
     find_if(_InputIterator __first, _InputIterator __last,
     ^
/usr/include/c++/5/bits/stl_algo.h:3806:5: note:   template argument
deduction/substitution failed:
bug.cpp:13:25: note:   couldn't deduce template parameter ‘_Predicate’
             std::isblank);