c++: make finish_non_static_data_member SFINAE enabled [PR105351]

Here since finish_non_static_data_member isn't SFINAE enabled, we
incorrectly emit an error when considering the first overload rather
than silently discarding it:

sfinae33.C: In substitution of ‘template<class T> A<T::value> f() [with T = B]’:
sfinae33.C:11:7:   required from here
sfinae33.C:5:31: error: invalid use of non-static data member ‘B::value’
    5 | template<class T> A<T::value> f();
      |                               ^

This patch makes the function SFINAE enabled in the usual way: give it a
complain parameter, check it before emitting an error, and pass it through
appropriately.

	PR c++/105351

gcc/cp/ChangeLog:

	* cp-tree.h (finish_non_static_data_member): Add defaulted
	complain parameter.
	* pt.cc (tsubst_copy_and_build): Pass complain to
	finish_non_static_data_member.
	* semantics.cc (finish_non_static_data_member): Respect complain
	parameter.
	(finish_qualified_id_expr): Pass complain to
	finish_non_static_data_member.

gcc/testsuite/ChangeLog:

	* g++.dg/template/sfinae33.C: New test.

3 files changed, 20 insertions, 13 deletions

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 6de29c0..8d7cf24 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -7615,7 +7615,8 @@ inline tree force_paren_expr_uneval 		(tree t)
 { return force_paren_expr (t, true); }
 extern tree maybe_undo_parenthesized_ref	(tree);
 extern tree maybe_strip_ref_conversion		(tree);
-extern tree finish_non_static_data_member       (tree, tree, tree);
+extern tree finish_non_static_data_member       (tree, tree, tree,
+						 tsubst_flags_t = tf_warning_or_error);
 extern tree begin_stmt_expr			(void);
 extern tree finish_stmt_expr_expr		(tree, tree);
 extern tree finish_stmt_expr			(tree, bool);
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 3edee50..ac00290 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -21054,7 +21054,8 @@ tsubst_copy_and_build (tree t,
 	  }
 	else if (TREE_CODE (member) == FIELD_DECL)
 	  {
-	    r = finish_non_static_data_member (member, object, NULL_TREE);
+	    r = finish_non_static_data_member (member, object, NULL_TREE,
+					       complain);
 	    if (TREE_CODE (r) == COMPONENT_REF)
 	      REF_PARENTHESIZED_P (r) = REF_PARENTHESIZED_P (t);
 	    RETURN (r);
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 377f611..bfb737f 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -2141,7 +2141,8 @@ finish_parenthesized_expr (cp_expr expr)
    preceded by `.' or `->'.  */
 
 tree
-finish_non_static_data_member (tree decl, tree object, tree qualifying_scope)
+finish_non_static_data_member (tree decl, tree object, tree qualifying_scope,
+			       tsubst_flags_t complain /* = tf_warning_or_error */)
 {
   gcc_assert (TREE_CODE (decl) == FIELD_DECL);
   bool try_omp_private = !object && omp_private_member_map;
@@ -2172,12 +2173,15 @@ finish_non_static_data_member (tree decl, tree object, tree qualifying_scope)
   if (is_dummy_object (object) && cp_unevaluated_operand == 0
       && (!processing_template_decl || !current_class_ref))
     {
-      if (current_function_decl
-	  && DECL_STATIC_FUNCTION_P (current_function_decl))
-	error ("invalid use of member %qD in static member function", decl);
-      else
-	error ("invalid use of non-static data member %qD", decl);
-      inform (DECL_SOURCE_LOCATION (decl), "declared here");
+      if (complain & tf_error)
+	{
+	  if (current_function_decl
+	      && DECL_STATIC_FUNCTION_P (current_function_decl))
+	    error ("invalid use of member %qD in static member function", decl);
+	  else
+	    error ("invalid use of non-static data member %qD", decl);
+	  inform (DECL_SOURCE_LOCATION (decl), "declared here");
+	}
 
       return error_mark_node;
     }
@@ -2219,8 +2223,9 @@ finish_non_static_data_member (tree decl, tree object, tree qualifying_scope)
     {
       tree access_type = TREE_TYPE (object);
 
-      perform_or_defer_access_check (TYPE_BINFO (access_type), decl,
-				     decl, tf_warning_or_error);
+      if (!perform_or_defer_access_check (TYPE_BINFO (access_type), decl,
+					  decl, complain))
+	return error_mark_node;
 
       /* If the data member was named `C::M', convert `*this' to `C'
 	 first.  */
@@ -2234,7 +2239,7 @@ finish_non_static_data_member (tree decl, tree object, tree qualifying_scope)
       ret = build_class_member_access_expr (object, decl,
 					    /*access_path=*/NULL_TREE,
 					    /*preserve_reference=*/false,
-					    tf_warning_or_error);
+					    complain);
     }
   if (try_omp_private)
     {
@@ -2396,7 +2401,7 @@ finish_qualified_id_expr (tree qualifying_class,
     {
       push_deferring_access_checks (dk_no_check);
       expr = finish_non_static_data_member (expr, NULL_TREE,
-					    qualifying_class);
+					    qualifying_class, complain);
       pop_deferring_access_checks ();
     }
   else if (BASELINK_P (expr))