[Bug c++/60177] New: Unable to deduce template base of derived class in function template accepting a simple-template-id

[Bug c++/60177] New: Unable to deduce template base of derived class in function template accepting a simple-template-id

[filip.roseen at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60177

            Bug ID: 60177
           Summary: Unable to deduce template base of derived class in
                    function template accepting a simple-template-id
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: filip.roseen at gmail dot com

template<class> struct Base { };

struct Derived : Base<void> { };

template<template<typename> class TT, typename T>
void func (TT<T>) { }

int main () {
  func (Derived { });
}


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

main.cpp: In function 'int main()':
main.cpp:9:20: error: no matching function for call to 'func(Derived)'
   func (Derived { });
                    ^
main.cpp:9:20: note: candidate is:
main.cpp:6:6: note: template<template<class> class TT, class T> void
func(TT<T>)
 void func (TT<T>) { }
      ^
main.cpp:6:6: note:   template argument deduction/substitution failed:
main.cpp:9:20: note:   can't deduce a template for 'TT<T>' from non-template
type 'Derived'
   func (Derived { });

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

gcc rejects the snippet which is a violation of [temp.deduct.call]/4 (`clang`
and `msvc` accepts the code).

`TT<T>` is a `simple-template-id` and the standard says that if a derived type
is passed to such context it should be deduced to a suitable base of that
passed type. 

Correct behavior is that the deduced template parameters for `func (Derived
{})` should be `TT = Base, T = void`.

[Bug c++/60177] Unable to deduce template base of derived class in call to function taking a `simple-template-id`

[filip.roseen at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60177

--- Comment #1 from Filip Roséen <filip.roseen at gmail dot com> ---
Created attachment 32133
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32133&action=edit
testcase.cpp
>From gcc-bugs-return-443544-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Fri Feb 14 10:21:23 2014
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From: "ktietz at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/60193] [4.7.4/4.8/4.9 regression] ICE on big nested frame
Date: Fri, 14 Feb 2014 10:21:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id`193

Kai Tietz <ktietz at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |ASSIGNED

--- Comment #4 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Confirmed.  It seems to be related to array-size?!?

During debugging I found that r10 seems to live, and rax doesn't. I will look
into it.

[Bug c++/60177] Unable to deduce template base of derived class in call to function taking a `simple-template-id`

[ville.voutilainen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60177

Ville Voutilainen <ville.voutilainen at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-12-14
                 CC|                            |ville.voutilainen at gmail dot com
     Ever confirmed|0                           |1
      Known to fail|                            |4.8.2, 4.9.1, 5.0

--- Comment #2 from Ville Voutilainen <ville.voutilainen at gmail dot com> ---
Clang accepts the code.