tests/base_var_type_evolution_null.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2010 Jean Privat <jean@pryen.org>
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 import kernel
  18
  19 class A
  20 end
  21
  22 class B
  23         super A
  24 end
  25
  26 fun rand: Bool do return true
  27
  28 fun eat_na(a: nullable A) do 'a'.output
  29 fun eat_a(a: A) do 'A'.output
  30 fun eat_nb(b: nullable B) do 'b'.output
  31 fun eat_b(b: B) do 'B'.output
  32
  33 var a: nullable Object = null
  34 a = new B
  35 if rand then
  36         a = null #!alt1#
  37         #alt2#a = new A
  38         #alt3#a = new B
  39 end
  40 eat_na(a)
  41 #alt2#eat_a(a)
  42 eat_nb(a)
  43 #alt1#eat_b(a)
  44 #alt3#eat_b(a)
  45 #alt4#eat_b(a)
  46 '\n'.output
  47
  48 # a is 'nullable B' here
  49 if rand then
  50         a = new A
  51 end
  52 eat_na(a)
  53 #alt5#eat_a(a)
  54 #alt6#eat_nb(a)
  55 '\n'.output
  56 # a is 'nullable A' here
  57
  58 if rand then
  59         a = new B
  60 else
  61         a = new B
  62         #alt7#a = new A
  63 end
  64 eat_b(a)
  65 '\n'.output
  66