http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53301
Bug #: 53301
Summary: Spurious -Wzero-as-null-pointer-constant with
reference arguments
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: ll...@randombit.net
Host: x86_64-unknown-linux-gnu
Target: x86_64-unknown-linux-gnu
Build: x86_64-unknown-linux-gnu
The following causes a warning under -Wzero-as-null-pointer-constant:
"""
class x { public: x(int v) {} };
void foo(const x& = 0);
"""
wnull.cpp:4:22: warning: zero as null pointer constant
[-Wzero-as-null-pointer-constant]
void foo(const x& = 0);
The warning is avoided if the argument is passed as a non-reference type or if
the default argument is `x(0)`. Likely the reference type is being treated
identically to a pointer type even though in this case the value is used to
initialize the underlying type, not the reference.
$ g++-4.8.0-r187195 -v
Using built-in specs.
COLLECT_GCC=/usr/local/gcc-4.8.0-r187195/bin/g++-4.8.0-r187195
COLLECT_LTO_WRAPPER=/usr/local/gcc-4.8.0-r187195/libexec/gcc/x86_64-unknown-linux-gnu/4.8.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-svn/configure --prefix=/usr/local/gcc-4.8.0-r187195
--enable-languages=c,c++ --program-suffix=-4.8.0-r187195
Thread model: posix
gcc version 4.8.0 20120505 (experimental) (GCC)
