+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import core::kernel
+
+class A
+ fun foo(i: Int) do
+ 'F'.output
+ i.output
+ end
+
+ fun bar(i: Int): A do
+ 'B'.output
+ i.output
+ return self
+ end
+end
+
+fun test(a: nullable A) do
+ 'a'.output
+ (a == null).output
+ a?.foo(1)
+
+ var r = a?.bar(2)
+ 'r'.output
+ (r == null).output
+
+ a?.bar(10)?.bar(11)?.foo(12)
+ #alt2#a.bar(20).foo(21)
+ #alt3#a?.bar(20).foo(21)
+ #alt4#a.bar(20)?.foo(21)
+end
+
+var a = new A
+test(a)
+'\n'.output
+test(null)
+
+#alt1#a?.foo(10)
+#alt1#null?.foo(11)