https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87279
Bug ID: 87279
Summary: gcc violates §17.1.10
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sp2danny at gmail dot com
Target Milestone: ---
All versions of gcc (tested with godbolt) fails to compile the following:
# 1 "test.cpp"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 1 "<command-line>" 2
# 1 "test.cpp"
template<class T> void f();
template<class T=int> void f() {}
int main() { f(); }
===========================================================================
Tested (on godbolt) with -std=c++11 , -std=c++14 , -std=c++17 , fails equally
on all.
Tested (on godbolt) with all versions from 4.1 to 8.2 , fails equally on all.
The -save-temps output (above) was generated with gcc 4.9.2
The output of gcc -v is:
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.9/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.9.2-10+deb8u1'
--with-bugurl=file:///usr/share/doc/gcc-4.9/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.9 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.9 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-vtable-verify
--enable-plugin --with-system-zlib --disable-browser-plugin
--enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.9-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --with-arch-32=i586 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.9.2 (Debian 4.9.2-10+deb8u1)
===========================================================================
Commandline used:
g++ -std=c++11 test.cpp
(not that it matters, it fails regardless of parameters)
The exact error is:
test.cpp: In function ‘int main()’:
test.cpp:4:16: error: no matching function for call to ‘f()’
int main() { f(); }
^
test.cpp:4:16: note: candidate is:
test.cpp:3:28: note: template<class T> void f()
template<class T=int> void f() {}
^
test.cpp:3:28: note: template argument deduction/substitution failed:
test.cpp:4:16: note: couldn't deduce template parameter ‘T’
int main() { f(); }
===========================================================================
It may be noted that neither clang, MSVC nor icc have a problem with the above
code.
According to §17.1.10 the above code should be well defined.
