Converting a pointer to a derived class to a pointer to a base class before construction of base

[Fraser]

I don't think cppcheck can identify the undefined behaviour described in N4713 15.7 section 2. My compiler also does not identify this.

BTW is section the correct term?

[Daniel Marjamäki]

I believe that Cppcheck does not have such checker. Feel free to create a ticket in Trac. I would like that it contains a minimal example code with UB.

[Fraser]

Do I need a different account to log in to Trac? I have made posts before on it.

[Daniel Marjamäki]

yes.. well can you show a minimal example code here and I'll create a ticket.

[Fraser]

The following program can check a few things on this part of the standard. It is an extended version of the example in the standard.

struct A {
};

struct B : virtual A {
};

struct C : B {
C(int*);
};

struct D : virtual A {
D(A*);
int d;
};

struct X {
X(A);
X(int);
};

struct E : C, D, X {
E() : C(&d), // undefined behaviour: the construction of D has not started.
D(this), // undefined behaviour: upcast from E to A might use path E -> D -> A*
// but D is not constructed.
X(this) {} // defined behaviour: upon construction of X, C/B/D/A sublattice is fully constructed
};

struct F : C, D, X {
F() : C(&f), // defined behaviour: F() has started
D((C)this), // defined behaviour: F -> C is defined because F() has started,
// and C -> A* is defined because C is fully constructed
X(this) {} // defined behaviour: upon construction of X, C/B/D/A sublattice is fully constructed
int f;
};

int main(int argc, char* argv[])
{
return 0;
}

[Fraser]

Has a ticket been made for this?