#fixed code
                              private void test_global_scope(Scope scope) {
    assertThat(globalSymbolA.usages()).hasSize(4);
    assertThat(globalSymbolB.usages()).hasSize(1);

    Symbol arraySymbol = scope.getSymbol("$array");
    assertThat(arraySymbol.usages()).hasSize(1);

    assertThat(scope.getSymbol("$f").usages()).hasSize(1);
    assertThat(scope.getSymbol("h").usages()).hasSize(1);
    assertThat(scope.getSymbol("j").usages()).hasSize(1);

    assertThat(scope.getSymbol("$compoundVar").usages()).hasSize(2);
    assertThat(scope.getSymbol("$heredocVar").usages()).hasSize(2);
    assertThat(scope.getSymbol("$var").usages()).hasSize(2);

    Symbol classSymbol = scope.getSymbol("A");
    assertThat(classSymbol).isNotNull();
    assertThat(classSymbol.is(Kind.CLASS)).isTrue();
    assertThat(classSymbol.usages()).hasSize(3);

  }
#vulnerable code 
                              private void test_global_scope(Scope scope) {
    assertThat(globalSymbolA.usages()).hasSize(4);
    assertThat(globalSymbolB.usages()).hasSize(1);

    Symbol arraySymbol = scope.getSymbol("$array");
    assertThat(arraySymbol.usages()).hasSize(1);

    assertThat(scope.getSymbol("$f").usages()).hasSize(1);
    assertThat(scope.getSymbol("h").usages()).hasSize(1);
    assertThat(scope.getSymbol("j").usages()).hasSize(1);

    assertThat(scope.getSymbol("$compoundVar").usages()).hasSize(2);
    assertThat(scope.getSymbol("$heredocVar").usages()).hasSize(2);
    assertThat(scope.getSymbol("$var").usages()).hasSize(2);

    Symbol classSymbol = scope.getSymbol("A");
    assertThat(classSymbol).isNotNull();
    assertThat(classSymbol.is(Kind.CLASS)).isTrue();
    assertThat(classSymbol.usages()).hasSize(2);

  } 
                            #location 6 
                            #vulnerability type NULL_DEREFERENCE