[bugreport] Bug when defining method out of class

[Customer__Intel5]

Hi there. The following C++11 code fails to compile correctly:

#include <utility>

template <class F> struct foo {
  template <class... Args>
  auto operator()(Args &&... args)
      -> decltype(std::declval<F>()(std::forward<Args>(args)...));
};
template <class F>
template <class... Args>
auto foo<F>::operator()(Args &&... args)
    -> decltype(std::declval<F>()(std::forward<Args>(args)...)) {
  return F()(std::forward<Args>(args)...);
}

struct fun {
  int operator()(int) { return 0; }
};

int main() { return foo<fun>()(1); }

I get no compilation error with clang++ or g++...

[MalReddy_Y_Intel]

Hi,

Just FYI, This issue has been addressed in the 17.0 beta compiler which is available in the below link.

https://software.intel.com/en-us/articles/intel-parallel-studio-xe-2017-beta

Thanks,

Reddy

[Kittur_G_Intel]

Thanks Reddy, yes this is fixed in the beta compiler.

Kittur

[Customer__Intel5]

Unfortunately, I managed to trigger a similar bug with the beta version. I'm still struggling to build a minimal working example.

It's part of a bigger goal: trying to use icpc as a backend compiler for the pythran project (http://pythonhosted.org/pythran). Pythran runtime headers compile fine with g++ and clang++, but icpc chokes on it.

[Kittur_G_Intel]

Hi @sguelton,
I cannot reproduce with test samples on my end including the one you indicated in this thread. Appreciate if you can create a test reproducer. Can you compile with -P option to generate a preprocessed file and attach the generated .I file so I can reproduce the issue? Thanks for your help.

Kittur

[Customer__Intel5]

Hi Kittur, the (very large) preprocessed file is in attachment. Hope it helps...

If you manage to compile this file as clang and gcc does, I'll be able to officially support pythran + icc, which would be great news!

[Judith_W_Intel]

Thanks for the test case. I was able to reduce it to the following which does get a spurious error using our latest compiler:

Spurious errors:

sptxl15-489> icpc -std=c++11 -c bug.cpp
bug.cpp(33): error: declaration is incompatible with "auto C<Arg>::foo(int)->Arg" (declared at line 28)
  auto C<Arg>::foo(int i) -> decltype(this->fast(i))
               ^

bug.cpp(33): error: "this" may only be used inside a nonstatic member function
  auto C<Arg>::foo(int i) -> decltype(this->fast(i))
                                      ^

compilation aborted for bug.cpp (code 2)
sptxl15-490>

// bug.cpp

template <class Arg>
struct C {
   Arg fast(int i);
   auto foo(int i) -> decltype(this->fast(i));
   template <class E> C<C> fast(E const &expr) const;  // somehow this overload causes problem
};

template <class Arg>
auto C<Arg>::foo(int i) -> decltype(this->fast(i))
{
  return true;
}

I have submitted a bug report in our internal bugs database under the number DPD200409734.

Again, thanks for letting us know...

Judy

[Kittur_G_Intel]

Great, thanks Judy I'll monitor this issue and let @sguelton, know as soon as the release with the fix is out.

Hi @sguelton - thanks for the reproducer and I'll keep you updated on the progress of this issue.

Kittur

[Customer__Intel5]

Thanks a lot Kittur and Judith! Let me know when I can download a new icc (preview version) and run it on the whole pythran database. That's a very good test case for icc :-)

[Kittur_G_Intel]

Sure, will do. Again, thanks for your patience through this towards resolution.

Kittur

[Customer__Intel5]

Hi there,

I've downloaded and tried the last icpc release, namely icpc (ICC) 16.0.3 20160415

It still fails to compile some basic pythran-generated programs... I'm attaching a faulty preprocessed source. Hope it helps!

[Kittur_G_Intel]

Thanks for letting us know. I'll look into reproducing the issue on your new attached .I file and will pass on the info to the team - appreciate much.

Regards,
Kittur

[Customer__Intel5]

Hi there - topic revival.

I've checked the latest release, and the problem is still there... any status on this?