[Bug c++/61488] New: Regression in template argument substitution in 4.9+

[Bug c++/61488] New: Regression in template argument substitution in 4.9+

[roland at digitalvampire dot org]

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::*)()’
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From: "D.Bahadir at GMX dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/61489] New: Wrong warning with -Wmissing-field-initializers.
Date: Thu, 12 Jun 2014 16:22:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61489

            Bug ID: 61489
           Summary: Wrong warning with -Wmissing-field-initializers.
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: D.Bahadir at GMX dot de

Created attachment 32928
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=32928&action=edit
test-case

This bug is related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36750 but
addresses C++ instead of C.

When compiling the following code (in C++11 mode) with
-Wmissing-field-initializers then almost all attempts to initialize
"sockaddr_in" result in compiler-warnings about uninitialized field-members.
However, as far as I understand, almost all initializations should be fine and
zero-initialize (?) all struct-members and the compiler-warnings should
therefore not occur.


<code>
// Compile this code with: g++ -std=c++11 -Wmissing-field-initializers bug.cpp

#include <netinet/in.h>

int main()
{
    struct sockaddr_in addr0;      // No warning. But really zero-initialized?
    //struct sockaddr_in addr1();  // No warning, but a function-declaration.
    struct sockaddr_in addr2 = {};    // In C++: Warning about all members.
                                      // In C: Warning about first member.
    struct sockaddr_in addr3 = {0};   // In C++: Warning about all members
                                      //         except the first one.
    struct sockaddr_in addr4 = {0,};  // Same here.
#ifdef __cplusplus
    struct sockaddr_in addr5 = sockaddr_in();  // No warning and (probably)
                                               // zero-initialized.
#endif
#if __cplusplus >= 201103L
    struct sockaddr_in addr6{};    // Warning about all members.
    struct sockaddr_in addr7{0};   // Warning about all members except the
                                   // first one.
    struct sockaddr_in addr8{0,};  // Same here.
    struct sockaddr_in addr9  = sockaddr_in{};    // Warning about all members.
    struct sockaddr_in addr10 = sockaddr_in{0};   // Warning about all members
                                                  // except the first one.
    struct sockaddr_in addr11 = sockaddr_in{0,};  // Same here.
#endif

    return 0;
}
</code>


When compiling this code the following warnings will be issued:

bug.cpp: In function ‘int main()’:
bug.cpp:9:33: warning: missing initializer for member ‘sockaddr_in::sin_family’
[-Wmissing-field-initializers]
     struct sockaddr_in addr2 = {};    // In C++: Warning about all members.
                                 ^
bug.cpp:9:33: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
bug.cpp:9:33: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:9:33: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
bug.cpp:11:34: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
     struct sockaddr_in addr3 = {0};   // In C++: Warning about all members
                                  ^
bug.cpp:11:34: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:11:34: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
bug.cpp:13:35: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
     struct sockaddr_in addr4 = {0,};  // Same here.
                                   ^
bug.cpp:13:35: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:13:35: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
bug.cpp:19:30: warning: missing initializer for member
‘sockaddr_in::sin_family’ [-Wmissing-field-initializers]
     struct sockaddr_in addr6{};    // Warning about all members.
                              ^
bug.cpp:19:30: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
bug.cpp:19:30: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:19:30: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
bug.cpp:20:31: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
     struct sockaddr_in addr7{0};   // Warning about all members except the
                               ^
bug.cpp:20:31: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:20:31: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
bug.cpp:22:32: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
     struct sockaddr_in addr8{0,};  // Same here.
                                ^
bug.cpp:22:32: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:22:32: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
bug.cpp:23:45: warning: missing initializer for member
‘sockaddr_in::sin_family’ [-Wmissing-field-initializers]
     struct sockaddr_in addr9  = sockaddr_in{};    // Warning about all
members.
                                             ^
bug.cpp:23:45: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
bug.cpp:23:45: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:23:45: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
bug.cpp:24:46: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
     struct sockaddr_in addr10 = sockaddr_in{0};   // Warning about all members
                                              ^
bug.cpp:24:46: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:24:46: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
bug.cpp:26:47: warning: missing initializer for member ‘sockaddr_in::sin_port’
[-Wmissing-field-initializers]
     struct sockaddr_in addr11 = sockaddr_in{0,};  // Same here.
                                               ^
bug.cpp:26:47: warning: missing initializer for member ‘sockaddr_in::sin_addr’
[-Wmissing-field-initializers]
bug.cpp:26:47: warning: missing initializer for member ‘sockaddr_in::sin_zero’
[-Wmissing-field-initializers]
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Subject: [Bug c++/61489] Wrong warning with -Wmissing-field-initializers.
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ida489

--- Comment #1 from Deniz Bahadir <D.Bahadir at GMX dot de> ---
This does not only occur with GCC 4.9.0 but also with older ones like 4.7 and
4.8.

[Bug c++/61488] Regression in template argument substitution in 4.9+

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61488

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-06-13
                 CC|                            |jason at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |jason at gcc dot gnu.org
     Ever confirmed|0                           |1

[Bug c++/61488] [4.9/4.10 regression] Regression in template argument substitution in 4.9+

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61488

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Mon Jun 16 11:50:14 2014
New Revision: 211704

URL: https://gcc.gnu.org/viewcvs?rev=211704&root=gcc&view=rev
Log:
    PR c++/61488
    * pt.c (check_valid_ptrmem_cst_expr): Fix for template context.

Added:
    trunk/gcc/testsuite/g++.dg/template/ptrmem28.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/pt.c

[Bug c++/61488] [4.9/4.10 regression] Regression in template argument substitution in 4.9+

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61488

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.9.1

[Bug c++/61488] [4.9 regression] Regression in template argument substitution in 4.9+

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61488

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
      Known to work|                            |4.10.0, 4.8.3
            Version|unknown                     |4.9.0
            Summary|[4.9/4.10 regression]       |[4.9 regression] Regression
                   |Regression in template      |in template argument
                   |argument substitution in    |substitution in 4.9+
                   |4.9+                        |

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar.

[Bug c++/61488] [4.9 regression] Regression in template argument substitution in 4.9+

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61488

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Mon Jun 30 12:36:37 2014
New Revision: 212145

URL: https://gcc.gnu.org/viewcvs?rev=212145&root=gcc&view=rev
Log:
    PR c++/61488
    * pt.c (check_valid_ptrmem_cst_expr): Fix for template context.

Added:
    branches/gcc-4_9-branch/gcc/testsuite/g++.dg/template/ptrmem28.C
Modified:
    branches/gcc-4_9-branch/gcc/cp/ChangeLog
    branches/gcc-4_9-branch/gcc/cp/pt.c

[Bug c++/61488] [4.9 regression] Regression in template argument substitution in 4.9+

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61488

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for 4.9.1.