From e2e471d83d16449a325315c0f33dc52b90ce0fac Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 31 May 2022 16:31:35 -0400
Subject: [PATCH] c++: auto and dependent member name [PR105734]

In r12-3643 I improved our handling of type names after . or -> when
unqualified lookup doesn't find anything, but it needs to handle auto
specially.

	PR c++/105734

gcc/cp/ChangeLog:

	* parser.cc (cp_parser_postfix_dot_deref_expression): Use typeof
	if the expression has auto type.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/auto57.C: New test.
---
 gcc/cp/parser.cc                    |  2 +-
 gcc/testsuite/g++.dg/cpp0x/auto57.C | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/auto57.C

diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 0eefa740dc56..3fc73442da54 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -8262,7 +8262,7 @@ cp_parser_postfix_dot_deref_expression (cp_parser *parser,
       tree type = TREE_TYPE (postfix_expression);
       /* If we don't have a (type-dependent) object of class type, use
 	 typeof to figure out the type of the object.  */
-      if (type == NULL_TREE)
+      if (type == NULL_TREE || is_auto (type))
 	type = finish_typeof (postfix_expression);
       parser->context->object_type = type;
     }
diff --git a/gcc/testsuite/g++.dg/cpp0x/auto57.C b/gcc/testsuite/g++.dg/cpp0x/auto57.C
new file mode 100644
index 000000000000..fedcfde2f0c5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/auto57.C
@@ -0,0 +1,15 @@
+// PR c++/105734
+// { dg-do compile { target c++11 } }
+
+namespace N {
+  struct A { };
+  A f(A);
+}
+
+template <class T>
+void bar() {
+  auto m = f(T());
+  m.~A();
+}
+
+void foo() { bar<N::A>(); }