Error equality without matching types

[mgudemann]

For the following program

public class NullPointer5
{
  void f()
  {
    Object o = new Object();
    if(null == o)
      assert false;
    assert true;
  }
  void g()
  {
    Object o = new Object();
    if(o == null)
      assert false;
    assert true;
  }
}

the result of checking --function NullPointer5.g is ok, while --function NullPointer.f fails with the above error.

The same error is triggered with --function Inheritance3.f in

class Inheritance3
{
  class A
  {
  }
  class B extends A
  {
  }
  void f()
  {
    A a = new A();
    B b = new B();
    if(a == b)
      assert false;
    assert true;
  }
}

[smowton]

Addressed in smowton@5787def

This stemmed from indirecting via a local variable, which was given an inconsistent type (sometimes A* and sometimes void*). This commit simply treats pointer-typed locals as void* under all circumstances, since the same variable can be used with different types in different places in any case. The void* pointers are downcast to their proper types when needed (e.g. at method call sites, field accesses).

[smowton]

Fixed in Cristina's test_gen branch