https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61636
Takatoshi Kondo <redboltz at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |redboltz at gmail dot com
--- Comment #17 from Takatoshi Kondo <redboltz at gmail dot com> ---
x.g([]{}) made the following compile error only if it is called *after* calling
f(x) without this->. It seems that a side effect of the problem. If I add
this-> to f(x), all errors are disappeared.
clang++ doesn't make a compile error.
Error message --------------------
ccc_this2.cpp:9:10: note: no known conversion for argument 1 from
‘X::defer_f()::<lambda(auto:1)> [with auto:1 = X]::<lambda()>’ to
‘std::function<void()>’
gcc_this2.cpp:7:10: error: ‘void X::f(T) [with T =
X::defer_f()::<lambda(auto:1)> [with auto:1 = X]::<lambda()>]’, declared using
local type ‘X::defer_f()::<lambda(auto:1)> [with auto:1 = X]::<lambda()>’, is
used but never defined [-fpermissive]
void f(T) {}
Code -----------------------------
#include <functional>
struct X
{
// function template
template <typename T>
void f(T) {}
// function that has std::function as a parameter
void g(std::function<void()> = std::function<void()>()) {}
// function (non template)
void h() {}
auto defer_f()
{
return [&] (auto x) {
x.g([]{}); // Compile passed calling before f(x)
f(x); // Compile error *1 (without this->)
x.f([]{}); // Compile passed
x.h(); // Compile passed
x.g(); // Compile passed
x.g([]{}); // Compile error (maybe side effect of *1)
};
}
};
int main()
{
X x;
x.defer_f()(x);
}
Tested compiler --------------
gcc -v
Using
built-in specs.
COLLECT_GCC=/usr/bin/gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/5.3.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /build/gcc-multilib/src/gcc-5-20160209/configure --prefix=/usr
--libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release
Thread model: posix
gcc version 5.3.0 (GCC)
clang++ -v
clang
version 3.7.1 (tags/RELEASE_371/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Found candidate GCC installation:
/usr/bin/../lib/gcc/x86_64-unknown-linux-gnu/5.3.0
Found candidate GCC installation:
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/5.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-unknown-linux-gnu/5.3.0
Found candidate GCC installation: /usr/lib64/gcc/x86_64-unknown-linux-gnu/5.3.0
Selected GCC installation: /usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/5.3.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
