[Moved to DR at the November, 2016 meeting.]

Proposed resolution (June, 2016):

1. Change 6.8 [basic.types] paragraph 9 as follows:

...called POD types. Cv-unqualified scalar types, trivially copyable class types (Clause 11 [class]), arrays of such types, and non-volatile const-qualified cv-qualified versions of these types (6.8.5 [basic.type.qualifier]) are collectively called trivially copyable types. Scalar types...

2. Delete bullet 12.2 of 11.4.5.3 [class.copy.ctor]:

A copy/move constructor for class X is trivial if it is not user-provided, its parameter-type-list is equivalent to the parameter-type-list of an implicit declaration, and if

• ...

• class X has no non-static data members of volatile-qualified type, and

• ...

3. Delete bullet 25.2 of 11.4.5.3 [class.copy.ctor]:

A copy/move assignment operator for class X is trivial if it is not user-provided, its parameter-type-list is equivalent to the parameter-type-list of an implicit declaration, and if

• ...

• class X has no non-static data members of volatile-qualified type, and

Notes from the February, 2016 meeting:

CWG agreed with the suggested direction for the changes in 11.4.5.3 [class.copy.ctor]; the use of “trivial” will be dealt with separately and not as part of the resolution of this issue.

The resolution of issue 496 included the addition of 11.4.5.3 [class.copy.ctor] paragraph 25. 2, making a class's copy/move constructor non-trivial if it has a non-static data member of volatile-qualified type. This change breaks the IA-64 ABI, so it has been requested that CWG reconsider this aspect of the resolution.

On a related note, the resolution of issue 496 also changed 6.8 [basic.types] paragraph 9, which makes volatile-qualified scalar types “trivial” but not “trivially copyable.” It is not clear why there is a distinction made here; the only actual use of “trivial type” in the Standard appears to be in the description of qsort, which should probably use “trivially copyable.” (See also issue 1746.)