[Bug c++/103684] New: Ambiguous template template overload resolution

[weidmann at acm dot org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103684

Bug ID: 103684
   Summary: Ambiguous template template overload resolution
   Product: gcc
   Version: 11.2.1
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c++
  Assignee: unassigned at gcc dot gnu.org
  Reporter: weidmann at acm dot org
  Target Milestone: ---

The following code compiles with -std=c++11, but does not with -std=c++17.
Works with clang.

#include 
#include 

template typename T> constexpr std::size_t hello()
{
return 2;
}

template typename T> constexpr
std::size_t hello()
{
return 3;
}

void foo()
{
auto i = hello();
auto j = hello();
}

[Bug c++/103684] Ambiguous template template overload resolution

[weidmann at acm dot org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103684

--- Comment #3 from Nicolas Weidmann  ---
Ok, thanks for the update!

[Bug libstdc++/114866] New: & out_ptr in freestanding

[weidmann at acm dot org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114866

Bug ID: 114866
   Summary:  & out_ptr in freestanding
   Product: gcc
   Version: 14.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: libstdc++
  Assignee: unassigned at gcc dot gnu.org
  Reporter: weidmann at acm dot org
  Target Milestone: ---

With gcc version 14.0.1 20240411 (Red Hat 14.0.1-0) (GCC) on x86_64 GNU/Linux.

Using the following command options:

g++ -std=c++23 -fno-rtti -fno-exceptions -fno-non-call-exceptions
-fno-unwind-tables -fno-use-cxa-atexit -fno-enforce-eh-specs -faligned-new
-fsized-deallocation -fpermissive   -m32 -ffreestanding -fomit-frame-pointer
-Os -fno-asynchronous-unwind-tables -fno-builtin -Wall -fanalyzer

I get the following error:

In file included from /usr/include/c++/14/memory:95,
...
/usr/include/c++/14/bits/out_ptr.h:57:22: error: ‘__is_shared_ptr’ was not
declared in this scope
   57 |   static_assert(!__is_shared_ptr<_Smart> || sizeof...(_Args) != 0,

Is #if _GLIBCXX_HOSTED missing around 

#if __cplusplus > 202002L
#  include 
#endif

> As a quick workaround for building my project, I define #define 
> _GLIBCXX_OUT_PTR_H before including 

[Bug c++/117281] New: Concepts and variadic template: internal compiler error

[weidmann at acm dot org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117281

Bug ID: 117281
   Summary: Concepts and variadic template: internal compiler
error
   Product: gcc
   Version: 14.2.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c++
  Assignee: unassigned at gcc dot gnu.org
  Reporter: weidmann at acm dot org
  Target Milestone: ---

g++ (Compiler-Explorer-Build-gcc--binutils-2.42) 14.2.0

Getting an internal compiler error when compiling the following code with 'g++
-std=c++20'

#include 
#include 

template using always_string = std::string;

template typename T> struct first_ok {
T value;
};

first_ok first;

template typename T> struct second_ok {
T value;
};

second_ok second;

template typename T> struct triggers_bug {
T value;
};

triggers_bug bad;