Question about warning not generated - uninitialized variable in template class

[Andrzej Ciereszko]

Hi,

I am evaluating cppcheck to see if will find uninitialized variables members/variables... of a templated class type. But it doesn't seem to.

Invoked like so:
/usr/local/bin/cppcheck --enable=all --xml-version=2

Here is my test code:

enum class ViewMode
{
 One   = 1,
 Two     = 2,
 Three  = 3,
 Four     = 4
};

class TestClass {
 public:
   TestClass() {}
};

template<typename T, bool C = std::is_copy_constructible<T>::value>
class TemplateTest
{
 public:

  TemplateTest() {}

  TemplateTest(const T& value)
   : value_(value)
  {}

  TemplateTest(const TemplateTest&) = delete;

  TemplateTest(TemplateTest<T, C>&& rhs)
      : value_(std::move(rhs.value_))
  {}

  TemplateTest(T&& value)
      : value_(std::move(value))
  {}
 private:
  T value_;

};

class StaticAnalysisTest {

 public:
  StaticAnalysisTest() {}

  void DoSomething() {

  }

 private:
  ViewMode viewMode_;     //this uninitialized warning is found
  TemplateTest<ViewMode> viewMode2_; //this one is not
};

[Andrzej Ciereszko]

I distilled the problem further:

class Foo
{
 private:
  int m_nValue;
 public:
  Foo() {};
  Foo(int value) : m_nValue(value) {}
  int GetValue() { return m_nValue; }
};

class Bar
{
 public:
  Bar(){}

  void DoSomething() {
    Foo foo;
  }
};

This does not generate an unitialized variable warning, but when I comment out:

//Foo(int value) : m_nValue(value) {}

it does

[orbitcowboy]

Thank you for evaluating Cppcheck. A warning is given for the second example, in case you add the --inconclusive flag, for example:

$ cppcheck --enable=all --inconclusive uninitmembervar.cpp 
[uninitmembervar.cpp:6]: (warning, inconclusive) Member variable 'Foo::m_nValue' is not initialized in the constructor.

[Andrzej Ciereszko]

That works, thanks!!

[Andrzej Ciereszko]

That works, thanks!!

[Andrzej Ciereszko]

Ok a quick follow up, while that works, it still does not in the first example I gave. Here is distilled example of the template case:

template<typename T, bool C = std::is_copy_constructible<T>::value>
class Observable
{

    public:
      Observable() {}

    private:
      T value_;

};

class Bah
{
 public:
  Bah() {};

 private:

  Observable<int> tValue_;

};

This does not give a warning about tValue not being initialized. But if I remove the second parameter of the template (bool C), it does warn about tValue not being initialized.

Any idea why?

[orbitcowboy]

Hi,
it seems that you have found a case, where Cppcheck is currently blind. I have created a ticket about this test case on our bugtracker #8162.

Many thanks for evaluating Cppcheck!