https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85011
Bug ID: 85011
Summary: GCC complains that 2 identical function prototypes are
different
Product: gcc
Version: 7.3.1
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: m101010a at gmail dot com
Target Milestone: ---
$ cat x.cpp
template <class T> struct foo {
int x;
auto f1() -> decltype(x);
};
template <class T> auto foo<T>::f1() -> decltype ((this)->foo<T>::x) {}
$ g++ -v -fsyntax-only x.cpp
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/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 --enable-default-pie --enable-default-ssp
Thread model: posix
gcc version 7.3.1 20180312 (GCC)
COLLECT_GCC_OPTIONS='-v' '-fsyntax-only' '-shared-libgcc' '-mtune=generic'
'-march=x86-64'
/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/cc1plus -quiet -v -D_GNU_SOURCE x.cpp
-quiet -dumpbase x.cpp -mtune=generic -march=x86-64 -auxbase x -version
-fsyntax-only -o /dev/null
GNU C++14 (GCC) version 7.3.1 20180312 (x86_64-pc-linux-gnu)
compiled by GNU C version 7.3.1 20180312, GMP version 6.1.2, MPFR
version 4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1
/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1/x86_64-pc-linux-gnu
/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1/backward
/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/include
/usr/local/include
/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/include-fixed
/usr/include
End of search list.
GNU C++14 (GCC) version 7.3.1 20180312 (x86_64-pc-linux-gnu)
compiled by GNU C version 7.3.1 20180312, GMP version 6.1.2, MPFR
version 4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 7db9d5d3f13a1b145edda774ba2b8b66
x.cpp:5:25: error: prototype for ‘decltype (((foo<T>*)this)->foo<T>::x)
foo<T>::f1()’ does not match any in class ‘foo<T>’
template <class T> auto foo<T>::f1() -> decltype ((this)->foo<T>::x) {}
^~~~~~
x.cpp:3:7: error: candidate is: decltype (((foo<T>*)this)->foo<T>::x)
foo<T>::f1()
auto f1() -> decltype(x);
^~
This error message is nonsensical, since it claims that the prototype for f1 on
lines 3 and 5 differ, yet the error messages list the same prototype for each.
