This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 112e. See for the official list.


669. Confusing specification of the meaning of decltype

Section:  [dcl.type.simple]     Status: NAD     Submitter: Vera Lychagina     Date: 17 December 2007

The first bullet of [dcl.type.simple] paragraph 4 says,

There are two clarifications to this specification that would assist the reader. First, it would be useful to have a note highlighting the point that a parenthesized expression is neither an id-expression nor a member access expression.

Second, the phrase “the type of the entity named by e” is unclear as to whether cv-qualification in the object or pointer expression is or is not part of that type. Rephrasing this to read, “the declared type of the entity,” or adding “(ignoring any cv-qualification in the object expression or pointer expression),” would clarify the intent.

Rationale (February, 2008):

The text is clear enough. In particular, both of these points are illustrated in the last two lines of the example contrasting decltype(a->x) and decltype((a->x)): in the former, the expression has no parentheses, thus satisfying the requirements of the first bullet and yielding the declared type of A::x, while the second has parentheses, falling into the third bullet and picking up the const from the object expression in the member access.