Error on switch on variable in base class

[mgudemann]

This program

public class Inheritance2
{
  int x;
  public class A extends Inheritance2
  {
    void m1(int i)
    {
      if (x == 1)
        assert(true);
      else
        assert(false);
    }
    void m2(int i)
    {
      switch(x)
        {
        case 1:
          assert(true);
          break;
        default:
          assert(false);
          break;
        }
    }

    void test1(int i)
    {
      m1(i);
    }
    void test2(int i)
    {
      m2(i);
    }
  }
}

correctly reports on cbmc --function "Inheritance2\$A.test1" Inheritance2.class

** Results:
[assertion.1] assertion at file Inheritance2.java line 11: FAILURE
[assertion.2] assertion at file Inheritance2.java line 21: SUCCESS

but fails on cbmc --function "Inheritance2\$A.test2" Inheritance2.class with

size of program expression: 57 steps
simple slicing removed 8 assignments
Generated 1 VCC(s), 1 remaining after simplification
Passing problem to propositional reduction
converting SSA
component x not found in structure