[PATCH] c++: clear tf_partial et al in instantiate_template [PR108960]

[Marek Polacek <polacek@redhat.com>]

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

-- >8 --

In <https://gcc.gnu.org/pipermail/gcc-patches/2023-February/612929.html>
we concluded that we might clear all flags except tf_warning_or_error
when performing instantiate_template.

	PR c++/108960

gcc/cp/ChangeLog:

	* pt.cc (lookup_and_finish_template_variable): Don't clear tf_partial
	here.
	(instantiate_template): Reset all complain flags except
	tf_warning_or_error.
---
 gcc/cp/pt.cc | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 21b08a6266a..265e2a59a52 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -10396,12 +10396,6 @@ lookup_and_finish_template_variable (tree templ, tree targs,
   tree var = lookup_template_variable (templ, targs, complain);
   if (var == error_mark_node)
     return error_mark_node;
-  /* We may be called while doing a partial substitution, but the
-     type of the variable template may be auto, in which case we
-     will call do_auto_deduction in mark_used (which clears tf_partial)
-     and the auto must be properly reduced at that time for the
-     deduction to work.  */
-  complain &= ~tf_partial;
   var = finish_template_variable (var, complain);
   mark_used (var);
   return var;
@@ -22008,6 +22002,14 @@ instantiate_template (tree tmpl, tree orig_args, tsubst_flags_t complain)
   if (tmpl == error_mark_node)
     return error_mark_node;
 
+  /* The other flags are not relevant anymore here, especially tf_partial
+     shouldn't be set.  For instance, we may be called while doing a partial
+     substitution of a template variable, but the type of the variable
+     template may be auto, in which case we will call do_auto_deduction
+     in mark_used (which clears tf_partial) and the auto must be properly
+     reduced at that time for the deduction to work.  */
+  complain &= tf_warning_or_error;
+
   gcc_assert (TREE_CODE (tmpl) == TEMPLATE_DECL);
 
   if (modules_p ())

base-commit: 6e424febfbcb27c21a7fe3a137e614765f9cf9d2
-- 
2.41.0