lp:mir FTBFS: surface_info.h:52:13: error: looser throw specifier for ‘virtual mir::input::SurfaceInfoController::~SurfaceInfoController()’

... let's try this new Bugzilla ;)

This is an internal reminder that it would be nice to have implemented quite soon the resolution of core/1123:

  http://www.open-std.org/JTC1/SC22/WG21/docs/cwg_defects.html#1123

For sure the library would immediately benefit, no more explicitly noexcept destructors in a lot of places.

Created attachment 26711
A testcase for N3204

Attached a testcase for N3204 ;)

We don't want front-end testcases that rely on <iostream> and need to check what gets printed. A better test would use static_assert, but would also test cases with both throwing and non-throwing base class and members.

Created attachment 26721
A updated testcase

OK, here is a take two!

Jason, I'm glad to work on this (if you don't have anything better to do ;) Any tips for me? Shouldn't be so hard but I'm still a bit lost...

Of course I meant "if you have something better to do ;)"

I'm making some progress understanding these parts of the front-end.

For example the following trivial patchlet passes the testcase ;) But, seriously, I'm not sure whether we really need a full fledged build_exception_variant, whether we have to do something about LAZY_* things, and much, much, more.

Index: class.c
===================================================================
--- class.c (revision 185722)
+++ class.c (working copy)
@@ -1001,6 +1001,10 @@ add_method (tree type, tree method, tree using_dec
                   "destructor",
                   type);
        }
+ else if (cxx_dialect >= cxx0x
+ && !TYPE_RAISES_EXCEPTIONS (TREE_TYPE (method)))
+ TREE_TYPE (method) = build_exception_variant (TREE_TYPE (method),
+ noexcept_true_spec);
     }
   else
     {

This doesn't compile, for example:

struct B
{
  ~B();
};

B::~B() { }

The latter issue could be addressed by something like:

Index: decl.c
===================================================================
--- decl.c (revision 185715)
+++ decl.c (working copy)
@@ -1136,7 +1136,10 @@ check_redeclaration_exception_specification (tree
   if ((pedantic || ! DECL_IN_SYSTEM_HEADER (old_decl))
       && ! DECL_IS_BUILTIN (old_decl)
       && flag_exceptions
- && !comp_except_specs (new_exceptions, old_exceptions, ce_normal))
+ && !comp_except_specs (new_exceptions, old_exceptions, ce_normal)
+ && !(DECL_DESTRUCTOR_P (new_decl)
+ && cxx_dialect >= cxx0x
+ && !new_exceptions && TYPE_NOEXCEPT_P (old_type)))
     {
       error ("declaration of %qF has a different exception specifier",
       new_decl);

Author: paolo
Date: Mon Apr 2 00:13:30 2012
New Revision: 186058

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186058
Log:
/cp
2012-04-01 Paolo Carlini <email address hidden>

 PR c++/50043
 * class.c (deduce_noexcept_on_destructor,
 deduce_noexcept_on_destructors): New.
 (check_bases_and_members): Call the latter.
 * decl.c (grokfndecl): Call the former.
 * method.c (implicitly_declare_fn): Not static.
 * cp-tree.h (deduce_noexcept_on_destructor, implicitly_declare_fn):
 Declare

/testsuite
2012-04-01 Paolo Carlini <email address hidden>

 PR c++/50043
 * g++.dg/cpp0x/noexcept17.C: New.
 * g++.old-deja/g++.eh/cleanup1.C: Adjust.
 * g++.dg/tree-ssa/ehcleanup-1.C: Likewise.
 * g++.dg/cpp0x/noexcept01.C: Likewise.
 * g++.dg/eh/init-temp1.C: Likewise.
 * g++.dg/eh/ctor1.C: Likwise.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/noexcept17.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/class.c
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/decl.c
    trunk/gcc/cp/method.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/cpp0x/noexcept01.C
    trunk/gcc/testsuite/g++.dg/eh/ctor1.C
    trunk/gcc/testsuite/g++.dg/eh/init-temp1.C
    trunk/gcc/testsuite/g++.dg/tree-ssa/ehcleanup-1.C
    trunk/gcc/testsuite/g++.old-deja/g++.eh/cleanup1.C

Done. Library clean-ups will follow.

*** Bug 51295 has been marked as a duplicate of this bug. ***

*** Bug 53613 has been marked as a duplicate of this bug. ***

How about back port this patch to 4.7 branch?
It cause a lot of compile error which easily confuse programmers.

(In reply to comment #9)
> Author: paolo
> Date: Mon Apr 2 00:13:30 2012
> New Revision: 186058
>
> URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186058
> Log:
> /cp
> 2012-04-01 Paolo Carlini <email address hidden>
>
> PR c++/50043
> * class.c (deduce_noexcept_on_destructor,
> deduce_noexcept_on_destructors): New.
> (check_bases_and_members): Call the latter.
> * decl.c (grokfndecl): Call the former.
> * method.c (implicitly_declare_fn): Not static.
> * cp-tree.h (deduce_noexcept_on_destructor, implicitly_declare_fn):
> Declare
>
> /testsuite
> 2012-04-01 Paolo Carlini <email address hidden>
>
> PR c++/50043
> * g++.dg/cpp0x/noexcept17.C: New.
> * g++.old-deja/g++.eh/cleanup1.C: Adjust.
> * g++.dg/tree-ssa/ehcleanup-1.C: Likewise.
> * g++.dg/cpp0x/noexcept01.C: Likewise.
> * g++.dg/eh/init-temp1.C: Likewise.
> * g++.dg/eh/ctor1.C: Likwise.
>
> Added:
> trunk/gcc/testsuite/g++.dg/cpp0x/noexcept17.C
> Modified:
> trunk/gcc/cp/ChangeLog
> trunk/gcc/cp/class.c
> trunk/gcc/cp/cp-tree.h
> trunk/gcc/cp/decl.c
> trunk/gcc/cp/method.c
> trunk/gcc/testsuite/ChangeLog
> trunk/gcc/testsuite/g++.dg/cpp0x/noexcept01.C
> trunk/gcc/testsuite/g++.dg/eh/ctor1.C
> trunk/gcc/testsuite/g++.dg/eh/init-temp1.C
> trunk/gcc/testsuite/g++.dg/tree-ssa/ehcleanup-1.C
> trunk/gcc/testsuite/g++.old-deja/g++.eh/cleanup1.C

I have tested to apply this patch to 4.7 branch, everythings goes well.
Since it breaks already existing code, anybody can do commit backport to 4.7 branch?

(In reply to comment #13)
> How about back port this patch to 4.7 branch?
> It cause a lot of compile error which easily confuse programmers.
> (In reply to comment #9)
> > Author: paolo
> > Date: Mon Apr 2 00:13:30 2012
> > New Revision: 186058
> >
> > URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186058
> > Log:
> > /cp
> > 2012-04-01 Paolo Carlini <email address hidden>
> >
> > PR c++/50043
> > * class.c (deduce_noexcept_on_destructor,
> > deduce_noexcept_on_destructors): New.
> > (check_bases_and_members): Call the latter.
> > * decl.c (grokfndecl): Call the former.
> > * method.c (implicitly_declare_fn): Not static.
> > * cp-tree.h (deduce_noexcept_on_destructor, implicitly_declare_fn):
> > Declare
> >
> > /testsuite
> > 2012-04-01 Paolo Carlini <email address hidden>
> >
> > PR c++/50043
> > * g++.dg/cpp0x/noexcept17.C: New.
> > * g++.old-deja/g++.eh/cleanup1.C: Adjust.
> > * g++.dg/tree-ssa/ehcleanup-1.C: Likewise.
> > * g++.dg/cpp0x/noexcept01.C: Likewise.
> > * g++.dg/eh/init-temp1.C: Likewise.
> > * g++.dg/eh/ctor1.C: Likwise.
> >
> > Added:
> > trunk/gcc/testsuite/g++.dg/cpp0x/noexcept17.C
> > Modified:
> > trunk/gcc/cp/ChangeLog
> > trunk/gcc/cp/class.c
> > trunk/gcc/cp/cp-tree.h
> > trunk/gcc/cp/decl.c
> > trunk/gcc/cp/method.c
> > trunk/gcc/testsuite/ChangeLog
> > trunk/gcc/testsuite/g++.dg/cpp0x/noexcept01.C
> > trunk/gcc/testsuite/g++.dg/eh/ctor1.C
> > trunk/gcc/testsuite/g++.dg/eh/init-temp1.C
> > trunk/gcc/testsuite/g++.dg/tree-ssa/ehcleanup-1.C
> > trunk/gcc/testsuite/g++.old-deja/g++.eh/cleanup1.C

*** Bug 61067 has been marked as a duplicate of this bug. ***