On Mon, Aug 25, 2025 at 04:00:37PM -0400, Jason Merrill wrote: > On 8/25/25 12:02 PM, Jakub Jelinek wrote: > > On Mon, Aug 25, 2025 at 11:55:24AM -0400, Patrick Palka wrote: > > > > The following patch fixes that by testing DECL_TEMPLATE_INFO, dunno > > > > what else would be more appropriate for this function is a template, > > > > maybe decl_dependent_p? > > > > > > I was going to suggest just replacing the !processing_template_decl check > > > with !in_template_context to distinguish a true template context but that > > > wouldn't work here because we also push a dummy template parameter list > > > when parsing an expansion statement... so failing that, your current > > > approach makes sense to me. > > > > Based on Jason's comment on the PARM_DECL tsubst_expr patch, another > > possibility is !uses_template_params (fco), either always, or > > in > > if (!processing_template_decl > > || (in_expansion_stmt && !uses_template_parms (fco))) > > form. > > I think changing !processing_template_decl to !uses_template_parms (fco) > makes sense.
The following passed bootstrap/regtest on x86_64-linux and i686-linux, ok for trunk? 2025-08-27 Jakub Jelinek <ja...@redhat.com> PR c++/121583 * semantics.cc (apply_deduced_return_type): Adjust fun->returns*_struct when !uses_template_parms (fco) instead of when !processing_template_decl. * g++.dg/cpp26/expansion-stmt23.C: New test. * g++.dg/cpp26/expansion-stmt24.C: New test. --- gcc/cp/semantics.cc.jj 2025-08-15 22:38:28.907872033 +0200 +++ gcc/cp/semantics.cc 2025-08-23 18:02:09.130079505 +0200 @@ -14213,7 +14213,7 @@ apply_deduced_return_type (tree fco, tre result); DECL_RESULT (fco) = result; - if (!processing_template_decl) + if (!uses_template_parms (fco)) if (function *fun = DECL_STRUCT_FUNCTION (fco)) { bool aggr = aggregate_value_p (result, fco); --- gcc/testsuite/g++.dg/cpp26/expansion-stmt23.C.jj 2025-08-23 17:49:13.816155626 +0200 +++ gcc/testsuite/g++.dg/cpp26/expansion-stmt23.C 2025-08-23 18:08:32.125064559 +0200 @@ -0,0 +1,17 @@ +// PR c++/121583 +// { dg-do compile { target c++14 } } +// { dg-options "" } + +auto +foo () +{ + template for (int i : { 0 }) // { dg-warning "'template for' only available with" "" { target c++23_down } } + return i; +} + +auto +bar () +{ + template for (auto i : { 0 }) // { dg-warning "'template for' only available with" "" { target c++23_down } } + return i; +} --- gcc/testsuite/g++.dg/cpp26/expansion-stmt24.C.jj 2025-08-23 18:08:46.988868108 +0200 +++ gcc/testsuite/g++.dg/cpp26/expansion-stmt24.C 2025-08-23 18:12:46.856697841 +0200 @@ -0,0 +1,10 @@ +// PR c++/121583 +// { dg-do compile { target c++14 } } +// { dg-options "" } + +auto +foo () +{ + template for (auto i : { 0, 1, 2LL }) // { dg-warning "'template for' only available with" "" { target c++23_down } } + return i; // { dg-error "inconsistent deduction for auto return type: 'int' and then 'long long int'" } +} Jakub