PR c++/85092 - C++17 ICE with unused list constructor.

	* call.c (conv_binds_ref_to_prvalue): Also count ck_identity
	from a TARGET_EXPR.

From-SVN: r259052

gcc/cp/ChangeLog

 2018-04-03  Jason Merrill  <jason@redhat.com>
 
+	PR c++/85092 - C++17 ICE with unused list constructor.
+	* call.c (conv_binds_ref_to_prvalue): Also count ck_identity
+	from a TARGET_EXPR.
+
 	PR c++/85113 - ICE with constexpr and __builtin_constant_p.
 	* constexpr.c (cxx_eval_builtin_function_call): Only defer
 	__builtin_constant_p if ctx->quiet.

gcc/cp/call.c

@@ -7611,6 +7611,9 @@ conv_binds_ref_to_prvalue (conversion *c)
     return true;
   if (c->kind == ck_user && TREE_CODE (c->type) != REFERENCE_TYPE)
     return true;
+  if (c->kind == ck_identity && c->u.expr
+      && TREE_CODE (c->u.expr) == TARGET_EXPR)
+    return true;
 
   return false;
 }

gcc/testsuite/g++.dg/cpp0x/initlist99.C

+// PR c++/85092
+// { dg-do compile { target c++11 } }
+
+#include <initializer_list>
+
+struct A
+{
+  A (std::initializer_list<char>);
+};
+
+A f ();
+
+A a { f () };