Field use triggers RuntimeException

[CatarinaGamboa]

Description
Runtime exception in the next case.

Minimal reproducer
Client:

public class ByteBufTest {

    public static final int TEST_BUFFER_SIZE = 128;

    private ByteBuffer mDirectBuffer;

    public ByteBufTest() {
        mDirectBuffer = ByteBuffer.allocateDirect(TEST_BUFFER_SIZE);
        byte[] buf = mDirectBuffer.array();
    }
}

Refinements:

@Ghost("boolean arrayBacked")
@ExternalRefinementsFor("java.nio.ByteBuffer")
public interface ByteBufferRefinements {

    // ---- Backing array access ----

    @StateRefinement(to="_ ? arrayBacked() : !arrayBacked()")
    boolean hasArray();

    @StateRefinement(from="arrayBacked()")
    byte[] array();

    @StateRefinement(from="arrayBacked()")
    int arrayOffset();
}

Expected behavior
Not RuntimeException. Also within the method we shuold be able to know the state of the object even if it is a field if that state is introduced in this scope.

Actual behavior
StackTrace:

java.lang.RuntimeException: 
Error while checking CtConstructorImpl
  on ByteBufTest() { 
  at /Users/cgamboa/git/task-examples/liquidjava-tasks/src/main/java/com/example/so_clients/bytebuffer48582520/ByteBufTest.java:14
  with 
Error while checking CtBlockImpl
  on { 
  at /Users/cgamboa/git/task-examples/liquidjava-tasks/src/main/java/com/example/so_clients/bytebuffer48582520/ByteBufTest.java:14
  with 
Error while checking CtLocalVariableImpl
  on buf = mDirectBuffer.array(); 
  at /Users/cgamboa/git/task-examples/liquidjava-tasks/src/main/java/com/example/so_clients/bytebuffer48582520/ByteBufTest.java:20
  with 
Error while checking CtInvocationImpl
  on mDirectBuffer.array(); 
  at /Users/cgamboa/git/task-examples/liquidjava-tasks/src/main/java/com/example/so_clients/bytebuffer48582520/ByteBufTest.java:20
  with Cannot invoke "liquidjava.processor.context.RefinedVariable.getType()" because "var" is null
    at liquidjava.processor.refinement_checker.TypeChecker.scan (TypeChecker.java:78)
    at spoon.reflect.visitor.CtScanner.scan (CtScanner.java:184)

Environment

• LiquidJava version / commit: verifier 0.0.26, Add Element Context to Exceptions #237
• Java version (java -version):
• OS: