Re: include/net/sock.h:2100:16: sparse: sparse: cast to non-scalar

[Al Viro <viro@zeniv.linux.org.uk>]

On Mon, Jan 12, 2026 at 01:37:22PM +0100, Peter Zijlstra wrote:

> > #define unqual_non_array(T) __typeof__(((T(*)(void))0)())
> > 
> > would do the right thing without that _Generic cascade and it'll work
> > just fine for e.g. kuid_t.  Using it for an array would trigger an error,
> > array-returning functions being forbidden...
> > 
> > Guys, do you have any problems with replacing __unqual_scalar_typeof()
> > uses with that thing?
> 
> There is also __typeof_unqual__, but I do not know if that is now
> supported by all compilers, if so that is the better option. If not,
> your function return type thing is awesome.

From experimenting with godbolt.org:
			clang		gcc		icc
__typeof_unqual__	>= 19.0.1	>= 14.1		no
this trick		>= 3.0.0	>= 8.4		>= 13.0.1
our minima		15.0.0		8.1

So __typeof_unqual__ is well out of our range; this trick is slightly
out of range, but nowhere near as bad.  Prior to 8.4 gcc had a bug
in that area, unfortunately ;-/

Might make sense to reconsider it next time we bump gcc minimum...