[Bug ada/36846] New: ICE with variadic templates partial specialisation

[Bug ada/36846] New: ICE with variadic templates partial specialisation

[tristan at wibberley dot org]

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This code ICEs. This isn't preprocessed but is trivial and the preprocessor
lines highlight a change that switches the ICE on and off so I've left it in to
help.

*****************************************
template<typename A, typename B>
struct pair;

template<typename... T>
struct pairs;

template<typename... AS, typename... BS>
struct pairs<pair<AS, BS>...> {
#ifndef NO_ICE
  struct mismatched_packs {};
#endif
};

template class pairs<
  pair<int, int>,
  pair<int, int>
>;
*****************************************

Using built-in specs.
Target: x86_64-unknown-linux-gnu
Configured with: ./configure --enable-languages=c++
Thread model: posix
gcc version 4.4.0 20080712 (experimental) (GCC) 
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-O3' '-c' '-std=c++0x' '-shared-libgcc'
'-mtune=generic'
 /usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.4.0/cc1plus -E -quiet -v
-D_GNU_SOURCE fail.cc -mtune=generic -std=c++0x -O3 -fpch-preprocess -o fail.ii
ignoring nonexistent directory
"/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0

/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0/x86_64-unknown-linux-gnu

/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0/backward
 /usr/local/include
 /usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.4.0/include
 /usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.4.0/include-fixed
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-O3' '-c' '-std=c++0x' '-shared-libgcc'
'-mtune=generic'
 /usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.4.0/cc1plus -fpreprocessed
fail.ii -quiet -dumpbase fail.cc -mtune=generic -auxbase fail -O3 -std=c++0x
-version -o fail.s
GNU C++ (GCC) version 4.4.0 20080712 (experimental) (x86_64-unknown-linux-gnu)
        compiled by GNU C version 4.4.0 20080712 (experimental), GMP version
4.2.2, MPFR version 2.3.1.
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: f6a0a74a0d4d0fcd1077c2c18ac6908a
fail.cc: In instantiation of ‘pairs<pair<int, int>, pair<int, int> >’:
fail.cc:14:   instantiated from here
fail.cc:10: error: mismatched argument pack lengths while expanding ‘pair<AS,
BS>’
fail.cc: In instantiation of ‘pairs<pair<int, int>, pair<int, int>
>::mismatched_packs’:
fail.cc:14:   instantiated from here
fail.cc:10: internal compiler error: tree check: expected class ‘type’, have
‘exceptional’ (error_mark) in instantiate_class_template, at cp/pt.c:6945
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


-- 
           Summary: ICE with variadic templates partial specialisation
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tristan at wibberley dot org
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] ICE with variadic templates partial specialisation

[tristan at wibberley dot org]

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------- Comment #1 from tristan at wibberley dot org  2008-08-16 23:34 -------
> fail.cc: In instantiation of ‘pairs<pair<int, int>, pair<int, int> >’:
> fail.cc:14:   instantiated from here
> fail.cc:10: error: mismatched argument pack lengths while expanding ‘pair<AS,
> BS>’
> fail.cc: In instantiation of ‘pairs<pair<int, int>, pair<int, int>
> >::mismatched_packs’:
> fail.cc:14:   instantiated from here
> fail.cc:10: internal compiler error: tree check: expected class ‘type’, have
> ‘exceptional’ (error_mark) in instantiate_class_template, at cp/pt.c:6945

4.3.1 doesn't ICE (I can't get details as somebody was kind enough to try this
for me) and instead reports:

t.cpp:10: error: mismatched argument pack lengths while expanding ‘pair<AS,
BS>‘
t.cpp:10: error: mismatched argument pack lengths while expanding ‘pair<AS,
BS>‘

where the ICE is reported above

with -DNO_ICE this is compiled successfully


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] ICE with variadic templates partial specialisation

[tristan at wibberley dot org]

------- Comment #2 from tristan at wibberley dot org  2008-08-22 00:22 -------
Created an attachment (id=16124)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16124&action=view)
ice when NO_ICE is not defined

This is the same source as in my original report but as an attachment.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] ICE with variadic templates partial specialisation

[tristan at wibberley dot org]

------- Comment #3 from tristan at wibberley dot org  2008-11-29 00:36 -------
Ping since this is a regression and has not yet been triaged.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] [4.3/4.4 regression] ICE with variadic templates partial specialization

[reichelt at gcc dot gnu dot org]

------- Comment #4 from reichelt at gcc dot gnu dot org  2008-12-31 20:20 -------
I'm not sure whether the code snippet is really valid or not,
but I can confirm the ICE nevertheless.

GCC 4.3.x already crashed, you probably need --enable-checking to see the ICE.

It's a regression, because the compiler crashes even without the -std=gnu++0x
switch.


-- 

reichelt at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |reichelt at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |ice-checking, monitored
   Last reconfirmed|0000-00-00 00:00:00         |2008-12-31 20:20:12
               date|                            |
            Summary|ICE with variadic templates |[4.3/4.4 regression] ICE
                   |partial specialization      |with variadic templates
                   |                            |partial specialization
   Target Milestone|---                         |4.3.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] [4.3/4.4 regression] ICE with variadic templates partial specialization

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2009-01-03 15:26 -------
valid or not?  If so then it's a rejects-valid, otherwise it is error-recovery.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dgregor at cs dot indiana
                   |                            |dot edu
             Status|NEW                         |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] [4.3/4.4 regression] ICE with variadic templates partial specialization

[tristan at wibberley dot org]

------- Comment #6 from tristan at wibberley dot org  2009-01-03 15:50 -------
Subject: Re:  [4.3/4.4 regression] ICE with variadic
 templates partial specialization

On Sat, 2009-01-03 at 15:26 +0000, rguenth at gcc dot gnu dot org wrote:
> 
> ------- Comment #5 from rguenth at gcc dot gnu dot org  2009-01-03 15:26 -------
> valid or not?  If so then it's a rejects-valid, otherwise it is error-recovery.

I had discussed these c++0x features in ##c++ and I came to the
conclusion that it was valid code. But I'm not an expert in c++0x, I
discovered this problem while experimenting when learning.

It accepts the code without the nested struct, it is only with a nested
struct that the code is rejected. I don't think a nested struct will
make it invalid and the behaviour of ambiguity analysis with a larger
example suggests the code is very carefully and consciously accepted
without that struct - agreeing with my studies and conversations on IRC.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] [4.3/4.4 regression] ICE with variadic templates partial specialization

[jason at gcc dot gnu dot org]

-- 

jason at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jason at gcc dot gnu dot org
                   |dot org                     |
             Status|WAITING                     |ASSIGNED
   Last reconfirmed|2008-12-31 20:20:12         |2009-01-06 16:13:55
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] [4.3/4.4 regression] ICE with variadic templates partial specialization

[jason at gcc dot gnu dot org]

------- Comment #7 from jason at gcc dot gnu dot org  2009-01-07 20:43 -------
Subject: Bug 36846

Author: jason
Date: Wed Jan  7 20:43:01 2009
New Revision: 143166

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=143166
Log:
        PR c++/35297
        PR c++/35477
        PR c++/35784
        PR c++/36846
        PR c++/38276
        * pt.c (check_default_tmpl_args): Don't complain about
        out-of-order parameter packs in the enclosing class
        or parameter packs after default args.
        (coerce_template_parms): If we have more than one
        parameter pack, don't flatten argument packs.
        (template_args_equal): Handle argument packs.
        (comp_template_args): Don't flatten argument packs.
        (check_instantiated_arg): Split out from...
        (check_instantiated_args): Here.  Handle arg packs.
        (convert_template_argument): Just check that nontype argument
        packs have the right type.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic92.C
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic93.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/pt.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic65.C
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic82.C
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic83.C


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846

[Bug c++/36846] [4.3/4.4 regression] ICE with variadic templates partial specialization

[jakub at gcc dot gnu dot org]

------- Comment #8 from jakub at gcc dot gnu dot org  2009-01-07 20:49 -------
Fixed.


-- 

jakub at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36846