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From: "richard-gccbugzilla at metafoo dot co.uk" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/109422] New: wrong depth used for template parameter mangling for lambdas in function signatures
Date: Wed, 05 Apr 2023 17:36:05 +0000	[thread overview]
Message-ID: <bug-109422-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109422

            Bug ID: 109422
           Summary: wrong depth used for template parameter mangling for
                    lambdas in function signatures
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: richard-gccbugzilla at metafoo dot co.uk
  Target Milestone: ---

Testcase:

struct C {
  template<typename T>
  void f(decltype([](T, auto) { return 0; })) {}  
};
void g() { C().f<int>({}); }

GCC mangles f<int> as _ZN1C1fIiEEvDTtlNS_UlT_T_E_EEE -- note that this is
mangling / numbering the lambda directly within C, which is not permitted by
http://itanium-cxx-abi.github.io/cxx-abi/abi.html#closure-types but seems like
the best choice (see https://github.com/itanium-cxx-abi/cxx-abi/issues/165).

But the mangling of the <lambda-sig> as T_T_ is definitely wrong -- two
different template parameters should not be mangled the same. This should
instead be mangled as T_TL__ under
https://github.com/itanium-cxx-abi/cxx-abi/issues/31#issuecomment-528122117

             reply	other threads:[~2023-04-05 17:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-05 17:36 richard-gccbugzilla at metafoo dot co.uk [this message]
2023-04-05 17:39 ` [Bug c++/109422] " richard-gccbugzilla at metafoo dot co.uk
2023-10-10 21:23 ` cvs-commit at gcc dot gnu.org
2023-11-17  2:42 ` jason at gcc dot gnu.org

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