https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95135
Bug ID: 95135
Summary: Inconsistent CTAD behaviour with the "new" operator.
Product: gcc
Version: 7.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gccbugreport at yandex dot com
Target Milestone: ---
Created attachment 48535
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48535&action=edit
The preprocessed file.
This is my first bug report, I hope it includes all the necessary information.
In any case, this bug is very easy to replicate.
===============
The code (main.cpp):
template<typename T>
struct X {
X(T _t) {}
};
template<typename T, typename U>
struct Y {
Y(T _t, U _u) {}
};
int main() {
X(1);
new X(1);
Y(1, 2);
new Y(1, 2); // This line causes the compilation error.
return 0;
}
===============
Compiled with:
gcc -v -save-temps -std=c++17 main.cpp -lstdc++
===============
Output:
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
7.5.0-3ubuntu1~18.04' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-7
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
--with-system-zlib --with-target-system-zlib --enable-objc-gc=auto
--enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none --without-cuda-driver
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++1z' '-mtune=generic'
'-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/7/cc1plus -E -quiet -v -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE main.cpp -mtune=generic -march=x86-64 -std=c++1z
-fpch-preprocess -fstack-protector-strong -Wformat -Wformat-security -o main.ii
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/7"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/7/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/7
/usr/include/x86_64-linux-gnu/c++/7
/usr/include/c++/7/backward
/usr/lib/gcc/x86_64-linux-gnu/7/include
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/7/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++1z' '-mtune=generic'
'-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/7/cc1plus -fpreprocessed main.ii -quiet
-dumpbase main.cpp -mtune=generic -march=x86-64 -auxbase main -std=c++1z
-version -fstack-protector-strong -Wformat -Wformat-security -o main.s
GNU C++14 (Ubuntu 7.5.0-3ubuntu1~18.04) version 7.5.0 (x86_64-linux-gnu)
compiled by GNU C version 7.5.0, GMP version 6.1.2, MPFR version 4.0.1,
MPC version 1.1.0, isl version isl-0.19-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++14 (Ubuntu 7.5.0-3ubuntu1~18.04) version 7.5.0 (x86_64-linux-gnu)
compiled by GNU C version 7.5.0, GMP version 6.1.2, MPFR version 4.0.1,
MPC version 1.1.0, isl version isl-0.19-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 3eb3dc290cd5714c3e1c3ae751116f07
main.cpp: In function ‘int main()’:
main.cpp:16:15: error: class template argument deduction failed:
new Y(1, 2); // This line causes the compilation error.
^
main.cpp:16:15: error: no matching function for call to ‘Y()’
main.cpp:8:5: note: candidate: template<class T, class U> Y(T, U)-> Y<T, U>
Y(T _t, U _u) {}
^
main.cpp:8:5: note: template argument deduction/substitution failed:
main.cpp:16:15: note: candidate expects 2 arguments, 0 provided
new Y(1, 2); // This line causes the compilation error.
===============
