[Bug c/65455] typeof _Atomic fails

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65455

--- Comment #10 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Wed, 18 Mar 2015, jens.gustedt at inria dot fr wrote:

> (Perhaps gcc interprets _Generic as you say, but even the standard committee
> doesn't agree on that interpretation, and other compiler implementors don't
> agree either. Nothing in the standard says that it is an rvalue, nor that it
> has to undergo any conversion. Conversion for non-evaluated expressions simply
> doesn't exist in the standard. The standard explicitly asks for compatible type
> of the expression itself, it says nothing about unqualified type.)

There isn't yet a conclusion to DR#423, but the committee discussion in 
N1892 says 'Specifically, the controlling expression of a generic 
selection "was very carefully not added" to the list of cases where lvalue 
conversion is not done.' (i.e. that conversion happens to all expressions 
unless excluded from happening).  There is no indication of a committee 
direction contradicting the approach I chose for GCC (even if the 
committee isn't quite sure of how to handle atomics there, and has 
suggested making qualifiers on function return types not part of the 
type).