[Bug c++/61471] New: redeclaration of default-argument in function template declaration not caught

[Bug c++/61471] New: redeclaration of default-argument in function template declaration not caught

[filip.roseen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61471

            Bug ID: 61471
           Summary: redeclaration of default-argument in function template
                    declaration not caught
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: filip.roseen at gmail dot com

Created attachment 32921
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=32921&action=edit
testcase.cpp

template<class T> void f(int=3);
template<class T> void f(int=3); // ill-formed

int main () { }

------------------------

`gcc` inaccurately accepts the above snippet, which is violating the following
[dcl.fct.default]p4:

 > A default argument shall not be redefined b a later declaration
 > (not even to the same value).

------------------------

By making `f` a non-template the violating is caught, and appropriate
diagnostics are shown.

[Bug c++/61471] redeclaration of default-argument in function template declaration not caught

[filip.roseen at gmail dot com]

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61471

--- Comment #1 from Filip Roséen <filip.roseen at gmail dot com> ---
Created attachment 32922
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=32922&action=edit
testcase-real.cpp

The previously attached `testcase.cpp` contains a code snippet for a related,
but different, bug.

See the newly attached testcase.cpp for contents matching the code in the
original post.
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From: "filip.roseen at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/61472] New: added default-argument in later declaration of function template not caught
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ida472

            Bug ID: 61472
           Summary: added default-argument in later declaration of
                    function template not caught
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: filip.roseen at gmail dot com

Created attachment 32923
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id2923&actioníit
testcase.cpp

template<class T> void f(int);
template<class T> void f(int=3);

int main () { }

-----------------------------

`gcc` inaccurately accepts the above snippet, which is violating the following
sentence from [dcl.fct.default]p4:

 > For non-template functions, default arguments can be added in later
 > declarations of a function in the same scope.

-----------------------------

[Bug c++/61471] redeclaration of default-argument in function template declaration not caught

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61471

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-06-11
     Ever confirmed|0                           |1

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
We diagnose this if the function template is instantiated. I'm not sure if
we're required to diagnose it for uninstantiated templates.

[Bug c++/61471] redeclaration of default-argument in function template declaration not caught

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61471

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Oops, I messed up my test - we don't diagnose this even at instantiation