https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61488
Bug ID: 61488
Summary: Regression in template argument substitution in 4.9+
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: roland at digitalvampire dot org
The following code compiles fine with gcc 4.8 (and clang 3.4 for giggles).
With gcc 4.9 I get the error shown; Debian's gcc-snapshot version of 4.10
behaves the same way.
The non-template member function fix() is accepted by all compilers, but 4.9
rejects the template member function repair(). I don't know of any C++
language reason why the body of repair() should be treated differently.
~$ cat a.cpp
struct A {
typedef int (A::*cont_func)();
template <A::cont_func> void wait(int);
int notify();
void fix() { wait<&A::notify>(0); } // OK
template <int> void repair() { wait<&A::notify>(0); }
};
~$ for CC in gcc-4.8 clang gcc-4.9; do echo "=== $CC ("`$CC --version`")" ===;
$CC -Wall -Werror -c a.cpp && echo SUCCESS; echo; done ; gcc-4.9 -v -c a.cpp
=== gcc-4.8 (gcc-4.8 (Debian 4.8.3-2) 4.8.3 Copyright (C) 2013 Free Software
Foundation, Inc. This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.) ===
SUCCESS
=== clang (Debian clang version 3.4.1-4 (tags/RELEASE_34/dot1-final) (based on
LLVM 3.4.1) Target: x86_64-pc-linux-gnu Thread model: posix) ===
SUCCESS
=== gcc-4.9 (gcc-4.9 (Debian 4.9.0-5) 4.9.0 Copyright (C) 2014 Free Software
Foundation, Inc. This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.) ===
a.cpp: In member function ‘void A::repair()’:
a.cpp:7:58: error: no matching function for call to ‘A::wait(int)’
template <int> void repair() { wait<&A::notify>(0); }
^
a.cpp:7:58: note: candidate is:
a.cpp:3:38: note: template<int (A::* <anonymous>)()> void A::wait(int)
template <A::cont_func> void wait(int);
^
a.cpp:3:38: note: template argument deduction/substitution failed:
a.cpp:7:58: error: ‘&((A*)this)->*A::notify’ is not a valid template argument
for type ‘int (A::*)()’
template <int> void repair() { wait<&A::notify>(0); }
^
a.cpp:7:58: error: it must be a pointer-to-member of the form ‘&X::Y’
a.cpp:7:58: error: could not convert template argument
‘&((A*)this)->*A::notify’ to ‘int (A::*)()’
Using built-in specs.
COLLECT_GCC=gcc-4.9
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.9.0-5'
--with-bugurl=file:///usr/share/doc/gcc-4.9/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.9 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.9 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap
--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-4.9-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.9-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --with-arch-32=i586 --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 4.9.0 (Debian 4.9.0-5)
COLLECT_GCC_OPTIONS='-v' '-c' '-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/4.9/cc1plus -quiet -v -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE a.cpp -quiet -dumpbase a.cpp -mtune=generic
-march=x86-64 -auxbase a -version -o /tmp/ccBdykTy.s
GNU C++ (Debian 4.9.0-5) version 4.9.0 (x86_64-linux-gnu)
compiled by GNU C version 4.9.0, GMP version 6.0.0, MPFR version 3.1.2-p3,
MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/4.9"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/4.9/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/4.9
/usr/include/x86_64-linux-gnu/c++/4.9
/usr/include/c++/4.9/backward
/usr/lib/gcc/x86_64-linux-gnu/4.9/include
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/4.9/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
GNU C++ (Debian 4.9.0-5) version 4.9.0 (x86_64-linux-gnu)
compiled by GNU C version 4.9.0, GMP version 6.0.0, MPFR version 3.1.2-p3,
MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: b8ef2963d5911ef424cca776623bf2bd
a.cpp: In member function ‘void A::repair()’:
a.cpp:7:58: error: no matching function for call to ‘A::wait(int)’
template <int> void repair() { wait<&A::notify>(0); }
^
a.cpp:7:58: note: candidate is:
a.cpp:3:38: note: template<int (A::* <anonymous>)()> void A::wait(int)
template <A::cont_func> void wait(int);
^
a.cpp:3:38: note: template argument deduction/substitution failed:
a.cpp:7:58: error: ‘&((A*)this)->*A::notify’ is not a valid template argument
for type ‘int (A::*)()’
template <int> void repair() { wait<&A::notify>(0); }
^
a.cpp:7:58: error: it must be a pointer-to-member of the form ‘&X::Y’
a.cpp:7:58: error: could not convert template argument
‘&((A*)this)->*A::notify’ to ‘int (A::*)()’
