https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118256
Bug ID: 118256
Summary: gcc fails to match the function parameter list when a
reinterpret_cast with rvalue reference is involved
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rush102333 at gmail dot com
Target Milestone: ---
The following code should be valid, despite the reinterpret_cast here actually
does not cast anything:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
constexpr void foo (int&& i) { i = 0; }
void bar(int&& i)
{
foo(reinterpret_cast<int&&>(i));
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GCC rejects it with the following diagnostic:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>: In function 'void bar(int&&)':
<source>:5:7: error: cannot bind rvalue reference of type 'int&&' to lvalue of
type 'int'
5 | foo(reinterpret_cast<int&&>(i));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:1:27: note: initializing argument 1 of 'constexpr void foo(int&&)'
1 | constexpr void foo (int&& i) { i = 0; }
| ~~~~~~^
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It's quite interesting that changing the type of 'i' from 'int&&' to
'int'(which makes the reinterpret_cast effective) can make the code
successfully compile.
MSVC, EDG and clang accept the code.
See https://godbolt.org/z/h5faP31fe
