https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111647
Bug ID: 111647
Summary: g++ accepts different c++ on -fchecking= anf
checking=2
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: slyfox at gcc dot gnu.org
Target Milestone: ---
Encountered when was reducing PR111642 where `make bootstrap4` fails. Reduced
example:
// $ cat rtl-tests.cc.cc
struct poly_int {
template <typename...> constexpr poly_int() : poly_int() {}
};
template <int> void run() { poly_int(); }
Here is the mismatch between -fchecking=0 and -fchecking=2:
$ /tmp/gb/./prev-gcc/xg++ -B/tmp/gb/./prev-gcc/ -c rtl-tests.cc.cc -o bug
-fchecking=0
$ /tmp/gb/./prev-gcc/xg++ -B/tmp/gb/./prev-gcc/ -c rtl-tests.cc.cc -o bug
-fchecking=2
rtl-tests.cc.cc: In instantiation of ‘constexpr poly_int::poly_int() [with
<template-parameter-1-1> = {}]’:
rtl-tests.cc.cc:4:39: required from here
rtl-tests.cc.cc:2:58: error: constructor delegates to itself
2 | template <typename...> constexpr poly_int() : poly_int() {}
|
I think it's an invalid code (clang rejects it as well), but I'm not sure.
AFAIU all -fchecking= options should handle it identically.
gcc is from r14-4339-geaa41a6dc127d8
$ /tmp/gb/./prev-gcc/xg++ -B/tmp/gb/./prev-gcc/ -v
Reading specs from /tmp/gb/./prev-gcc/specs
COLLECT_GCC=/tmp/gb/./prev-gcc/xg++
COLLECT_LTO_WRAPPER=/tmp/gb/./prev-gcc/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /home/slyfox/dev/git/gcc/configure --disable-multilib
--enable-languages=c,c++ CC='gcc -O1 -g0' CXX='g++ -O1 -g0'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20230929 (experimental) (GCC)
