On Tue, Nov 29, 2022 at 04:38:50PM -0500, Jason Merrill wrote:
> > --- gcc/testsuite/g++.dg/gomp/for-21.C.jj 2020-01-12 11:54:37.178401867
> > +0100
> > +++ gcc/testsuite/g++.dg/gomp/for-21.C 2022-11-29 13:06:59.038410557
> > +0100
> > @@ -54,9 +54,9 @@ void
> > f6 (S (&a)[10])
> > {
> > #pragma omp for collapse (2)
> > - for (auto [i, j, k] : a) // { dg-error "use of 'i'
> > before deduction of 'auto'" "" { target *-*-* } .-1 }
> > + for (auto [i, j, k] : a) // { dg-error "use of 'i'
> > before deduction of 'auto'" }
> > for (int l = i; l < j; l += k) // { dg-error "use of
> > 'j' before deduction of 'auto'" }
> > - ; // { dg-error "use of
> > 'k' before deduction of 'auto'" "" { target *-*-* } .-3 }
> > + ; // { dg-error "use of
> > 'k' before deduction of 'auto'" "" { target *-*-* } .-1 }
>
> Hmm, this error is surprising: since the initializer is non-dependent, we
> should have deduced immediately. I'd expect the same error as in the
> non-structured-binding cases, "* expression refers to iteration variable".
The reason was just to be consistent what is (unfortunately) emitted
in the other cases (!processing_template_decl or type dependent).
I guess I could try how much work would it be to deduce it sooner, but
generally it is pretty corner case, people rarely do this in OpenMP code.
Jakub
