https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87586
Bug ID: 87586
Summary: C++ code compiles with mismatched angle
brackets/parenthesis
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gavin.smith at playerbites dot com
Target Milestone: ---
Created attachment 44827
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44827&action=edit
Preprocessed File
I don't believe this code ought to compile due to the fact that there are
mismatched angle brackets. Off the bat, I apologise if I have this wrong (due
to things like digraphs):
#include <iostream>
template <typename TARGET, typename SOURCE>
inline TARGET cast_integral_type(const SOURCE n)
{
// Simplified code here. Production code makes use of `#include
<boost/numeric/conversion/cast.hpp>` here.
return static_cast<TARGET>(n);
}
template <class TYPE>
inline TYPE redundant_fn(TYPE x)
{
// Simplified code - was originally doing endian conversion
return x;
}
int main(int argc, char *argv[])
{
const int nRedundantVar = 0;
#if 0 // Tried to simplify - does not compile.
std::cout << cast_integral_type<uint16_t, int>(nRedundantVar)>(0x64) <<
std::endl; // Rect width
std::cout << cast_integral_type<uint16_t, int>(nRedundantVar)>(0x64) <<
std::endl; // Rect height
#endif
// BAD: Unexpectedly print "0".
std::cout << redundant_fn<uint16_t>(cast_integral_type<uint16_t,
int>(nRedundantVar)>(0x64)) << std::endl;
// BAD: Remove iostreams - Unexpectedly print "0".
int x = (redundant_fn<uint16_t>(cast_integral_type<uint16_t,
int>(nRedundantVar)>(0x64)));
std::cout << x << std::endl;
// OK
int y = redundant_fn<uint16_t>(cast_integral_type<uint16_t,
int>(0x64));
std::cout << y << std::endl;
return 0;
}
Preprocessed file attached. Reproducible in both 7.3.0 and 8.2.0 (using
packages made available via Ubuntu 18.04 package manager).
g++ -v:
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
8.2.0-1ubuntu2~18.04' --with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8
--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 --with-sysroot=/ --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 8.2.0 (Ubuntu 8.2.0-1ubuntu2~18.04)
Code sample built using:
g++ main.cpp -o test
