[Bug c++/59991] New: Recursive lambda capture in C++1y constexpr function template causes internal compiler error

[Bug c++/59991] New: Recursive lambda capture in C++1y constexpr function template causes internal compiler error

[pkeir at outlook dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59991

            Bug ID: 59991
           Summary: Recursive lambda capture in C++1y constexpr function
                    template causes internal compiler error
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pkeir at outlook dot com

Created attachment 31987
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31987&action=edit
The test case which produces the internal compiler error

The code below uses the C++1y feature of allowing declarations in constexpr
functions, but r should not be included in the lambda's capture list. There is
also an issue with excessive recursive template instantiation. In any case, the
code produces an internal compiler error starting with:

internal compiler error: in tsubst, at cp/pt.c:11350
   auto f = [r,x]() { return r(x); };

The full output and test case is attached. This was run under Ubuntu 13.10.

// $ g++ --version
// g++ (GCC) 4.9.0 20131201 (experimental)

template <typename T>
constexpr int r(T x) {
  auto f = [r,x]() { return r(x); };
  return 0;
}

int main(int argc, char *argv[])
{
  r(0);
  return 0;
}

[Bug c++/59991] Recursive lambda capture in C++1y constexpr function template causes internal compiler error

[pkeir at outlook dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59991

--- Comment #1 from Paul Keir <pkeir at outlook dot com> ---
Created attachment 31988
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31988&action=edit
The output following: g++ -std=c++1y bug.cpp

[Bug c++/59991] Recursive lambda capture in C++1y constexpr function template causes internal compiler error

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59991

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-03-16
                 CC|                            |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |4.8.5
     Ever confirmed|0                           |1

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Confirmed with 4.9/4.8.  This has been fixed on trunk with r210829.

[Bug c++/59991] Recursive lambda capture in C++1y constexpr function template causes internal compiler error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59991

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |5.0
   Target Milestone|4.8.5                       |---
      Known to fail|                            |4.8.5, 4.9.2