https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94772
Bug ID: 94772
Summary: [10 Regression] constructing constexpr variables fail
with delegated constexpr constructors
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gcc-bugs at marehr dot dialup.fu-berlin.de
Target Milestone: ---
Hi gcc!
The following code does not compile with gcc10 anymore:
```c++
struct foo
{
constexpr foo() noexcept = default;
// fails with gcc10; commenting : foo{} out works with gcc10
constexpr foo(int a, int b) : foo{}
{
bar += a + b;
}
int bar{};
};
int main()
{
constexpr foo bar{1, 2};
}
```
https://godbolt.org/z/brsFdo
All major compilers and gcc < 10 do support this, so I think this is a
regression.
```
> g++-git -std=c++2a
<source>: In function 'int main()':
<source>:15:27: in 'constexpr' expansion of 'foo(1, 2)'
<source>:8:13: error: modifying a const object '((foo*)this)->foo::bar' is not
allowed in a constant expression
8 | bar += a + b;
| ~~~~^~~~~~~~
<source>:15:19: note: originally declared 'const' here
15 | constexpr foo bar{1, 2};
|
```
Thank you!
