OK.
On Mon, Jan 2, 2017 at 3:11 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> As the testcase shows, if some initializers are type dependent, auto_result
> is still using auto, is not yet deduced and the deduction will happen during
> instantiation. So rejecting it due to inconsistent deduction when one
> type is int and another type auto (or vice versa) is wrong, during
> instantiation it could be still instantiated with initializers that are
> valid.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> Though, the PR also shows that we should do similar diagnostics about
> inconsistent auto deduction at instantiation time, but we don't have
> infrastructure for that (at tsubst time we don't know which variables
> were declared together in a single declaration, nor the auto_result
> for those vars where the auto deduction happened already during parsing).
> So I think further work is needed on this PR.
>
> 2017-01-02 Jakub Jelinek <ja...@redhat.com>
>
> PR c++/78693
> * parser.c (cp_parser_simple_declaration): Only complain about
> inconsistent auto deduction if auto_result doesn't use auto.
>
> * g++.dg/cpp0x/pr78693.C: New test.
>
> --- gcc/cp/parser.c.jj 2017-01-01 12:45:44.000000000 +0100
> +++ gcc/cp/parser.c 2017-01-02 14:02:49.690859759 +0100
> @@ -12770,9 +12770,11 @@ cp_parser_simple_declaration (cp_parser*
> if (cp_parser_error_occurred (parser))
> goto done;
>
> - if (auto_result)
> + if (auto_result
> + && (!processing_template_decl || !type_uses_auto (auto_result)))
> {
> - if (last_type && last_type != error_mark_node
> + if (last_type
> + && last_type != error_mark_node
> && !same_type_p (auto_result, last_type))
> {
> /* If the list of declarators contains more than one declarator,
> --- gcc/testsuite/g++.dg/cpp0x/pr78693.C.jj 2017-01-02 14:05:45.494582539
> +0100
> +++ gcc/testsuite/g++.dg/cpp0x/pr78693.C 2017-01-02 14:05:07.000000000
> +0100
> @@ -0,0 +1,31 @@
> +// PR c++/78693
> +// { dg-do compile { target c++11 } }
> +
> +template <class T>
> +void
> +foo (T t)
> +{
> + auto i = t, j = 1; // { dg-bogus "inconsistent deduction" }
> +}
> +
> +template <class T>
> +void
> +bar (T t)
> +{
> + auto i = 1, j = t, k = 2; // { dg-bogus "inconsistent deduction" }
> +}
> +
> +template <class T, class U>
> +void
> +foo (T t, U u)
> +{
> + auto i = t, j = u; // { dg-bogus "inconsistent deduction" }
> +}
> +
> +void
> +foo ()
> +{
> + foo (0);
> + bar (0);
> + foo (1, 2);
> +}
>
> Jakub
