http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52183
Bug #: 52183
Summary: Redeclaration of __this in lambda inside template
member function when calling static class function
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: stefan.bo...@gmx.de
When compiling
#include <functional>
struct A
{
template<class T>
void f (T x) {
std::function<void ()> aux;
aux = [&] () -> void{
s();
aux ();
};
}
static void s () { }
};
template void A::f<int> (int);
code is rejected by the compiler by the error message below. Expected behavior
is compilation without an error.
stefan@bluebox:/tmp$ g++-svn -std=c++0x -v --save-temps foo.cpp
Using built-in specs.
COLLECT_GCC=g++-svn
COLLECT_LTO_WRAPPER=/home/stefan/libexec/gcc/x86_64-unknown-linux-gnu/4.7.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../trunk/configure --enable-languages=c,c++
--prefix=/home/stefan --program-suffix=-svn --disable-multilib
Thread model: posix
gcc version 4.7.0 20120126 (experimental) (GCC)
COLLECT_GCC_OPTIONS='-std=c++11' '-v' '-save-temps' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
/home/stefan/libexec/gcc/x86_64-unknown-linux-gnu/4.7.0/cc1plus -E -quiet -v
-D_GNU_SOURCE foo.cpp -mtune=generic -march=x86-64 -std=c++11 -fpch-preprocess
-o foo.ii
ignoring nonexistent directory
"/home/stefan/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/home/stefan/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0
/home/stefan/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/x86_64-unknown-linux-gnu
/home/stefan/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/backward
/home/stefan/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/include
/usr/local/include
/home/stefan/include
/home/stefan/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/include-fixed
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-std=c++11' '-v' '-save-temps' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
/home/stefan/libexec/gcc/x86_64-unknown-linux-gnu/4.7.0/cc1plus -fpreprocessed
foo.ii -quiet -dumpbase foo.cpp -mtune=generic -march=x86-64 -auxbase foo
-std=c++11 -version -o foo.s
GNU C++ (GCC) version 4.7.0 20120126 (experimental) (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.7.0 20120126 (experimental), GMP version 5.0.1,
MPFR version 3.0.1-p3, MPC version 0.9
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
GNU C++ (GCC) version 4.7.0 20120126 (experimental) (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.7.0 20120126 (experimental), GMP version 5.0.1,
MPFR version 3.0.1-p3, MPC version 0.9
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: 587bcf77b9db77a91e3cc4b379a04aff
foo.cpp: In instantiation of ‘A::f(T) [with T = int]::<lambda()>’:
foo.cpp:10:7: required from ‘struct A::f(T) [with T = int]::<lambda()>’
foo.cpp:8:5: required from ‘void A::f(T) [with T = int]’
foo.cpp:17:29: required from here
foo.cpp:9:9: error: redeclaration of ‘A* const A::f(T) [with T =
int]::<lambda()>::__this’
foo.cpp:9:9: note: previous declaration ‘A* const A::f(T) [with T =
int]::<lambda()>::__this’
foo.cpp:9:9: error: redeclaration of ‘A* const this’
foo.cpp:9:9: error: ‘A* const this’ previously declared here
In file included from foo.cpp:1:0:
/home/stefan/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/functional:2172:2:
error: ‘typename std::enable_if<(! std::is_integral<_Functor>::value),
std::function<_Res(_ArgTypes ...)>&>::type std::function<_Res(_ArgTypes
...)>::operator=(_Functor&&) [with _Functor = A::f(T) [with T =
int]::<lambda()>; _Res = void; _ArgTypes = {}; typename std::enable_if<(!
std::is_integral<_Functor>::value), std::function<_Res(_ArgTypes ...)>&>::type
= std::function<void()>&]’, declared using local type ‘A::f(T) [with T =
int]::<lambda()>’, is used but never defined [-fpermissive]
