https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97341
Bug ID: 97341
Summary: Implicit casting from char** to const char* const* in
template argument failing
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: reikdas at gmail dot com
Target Milestone: ---
Created attachment 49332
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49332&action=edit
preprocessed file
Implicit casting of char** to a const char* const* by passing a char** variable
to a class template's argument like -
char *bar = (char*)"Hello1";
constexpr char** baz = &bar;
template <const char* const*> class foo {};
int main()
{
foo<baz> Foo;
return 1;
}
gives a compilation error -
test.cpp:7:12: error: the address of the ‘const char* const’ subobject of ‘bar’
is not a valid template argument
7 | foo<baz> Foo;
| ^
Output of g++ -v -save-temps -std=c++17 test.cpp -
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/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++,d --with-isl
--with-linker-hash-style=gnu --with-system-zlib --enable-__cxa_atexit
--enable-cet=auto --enable-checking=release --enable-clocale=gnu
--enable-default-pie --enable-default-ssp --enable-gnu-indirect-function
--enable-gnu-unique-object --enable-install-libiberty --enable-linker-build-id
--enable-lto --enable-multilib --enable-plugin --enable-shared
--enable-threads=posix --disable-libssp --disable-libstdcxx-pch
--disable-libunwind-exceptions --disable-werror
gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.2.0 (GCC)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++17' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus -E -quiet -v -D_GNU_SOURCE
test.cpp -mtune=generic -march=x86-64 -std=c++17 -fpch-preprocess -o test.ii
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/../../../../include/c++/10.2.0
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/../../../../include/c++/10.2.0/x86_64-pc-linux-gnu
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/../../../../include/c++/10.2.0/backward
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/include
/usr/local/include
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/include-fixed
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++17' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus -fpreprocessed test.ii -quiet
-dumpbase test.cpp -mtune=generic -march=x86-64 -auxbase test -std=c++17
-version -o test.s
GNU C++17 (GCC) version 10.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 10.2.0, GMP version 6.2.0, MPFR version
4.1.0, MPC version 1.1.0, isl version isl-0.21-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++17 (GCC) version 10.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 10.2.0, GMP version 6.2.0, MPFR version
4.1.0, MPC version 1.1.0, isl version isl-0.21-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 2affcd71b0797e2421aae734ab600c81
test.cpp: In function ‘int main()’:
test.cpp:7:12: error: the address of the ‘const char* const’ subobject of ‘bar’
is not a valid template argument
7 | foo<baz> Foo;
| ^
