https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65816
Bug ID: 65816
Summary: Constructor delegation does not perform
zero-initialization
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dyp-cpp at gmx dot net
In the following program, I expect the object `t` to be zero-initialized via
constructor delegation. Clang++ does this, but g++ 6.0 2015-04-20 does not.
-----------------------------
struct test
{
int m;
test() = default;
test(int) : test() {}
};
#include <iostream>
int main()
{
test t(0);
std::cout << t.m;
}
-----------------------------
While C++14 IS [class.base.init]p6 is unclear about this, as far as I can tell,
paragraph 7 implies (in the parenthesized clause) that the constructor
`test(int)` is required to value-initialize the object:
> The expression-list or braced-init-list in a mem-initializer is used to
> initialize the designated subobject (or, in the case of a delegating
> constructor, the complete class object) according to the initialization rules
> of 8.5 for direct-initialization.
The class `test` does not have a user-provided default constructor, hence
zero-initialization should be performed as per [dcl.init]p8.2
