Fix #15080 FP uninitMemberVarNoCtor for const and reference members

[autoantwort]

https://trac.cppcheck.net/ticket/15080

struct S {
    const std::array<std::uint8_t, 2> a;
    const std::vector<std::uint8_t>::const_iterator it;
};
S f(const std::vector<std::uint8_t>& v) {
    return S{ {}, v.cbegin() };
}

gives Member variable 'S::it' has no initializer. [uninitMemberVarNoCtor], and struct S { int a = 0; const int b; int& c; }; warns for b and c.

A non-static const or reference member without default member initializer can't stay uninitialized: for trivial types the implicit default constructor is deleted, so every instance must initialize it, and a const class type is default-constructed. These members are now skipped by the no-constructor check.

Since f90a76f (#15072) this also shows up for class templates whose member type is a using alias.

This PR was created by Claude Code (an AI coding agent) on behalf of @autoantwort.

🤖 Generated with Claude Code

[autoantwort]

Any further changes requested?

[danmar]

@claude review

[claude]

This branch also catches static members. createUsageList() keeps static members because isInitialized() filters them out later, so a static const or static reference member without an in-class initializer now marks the class as not default constructible. That suppresses every warning for the class, which is a new false negative:

struct S {
    int a = 0;
    static const int N;   // defined out of class
    int k;                // warned before this PR, not anymore
};

Suggest excluding static members, and adding a test for this case:

Suggested change

	} else if (var.isReference() || (var.isConst() && !var.isClass())) {
	} else if (!var.isStatic() && (var.isReference() || (var.isConst() && !var.isClass()))) {

[claude]

The approach makes sense: a const member of trivial type, or a reference member, with no initializer deletes the implicit default constructor, so every instance has to be initialized another way.

One issue (inline): static const and static reference members are in the usage list too. The new check doesn't exclude them, so a declaration like static const int N; turns off uninitMemberVarNoCtor for the whole class. That's a new false negative. It needs a !var.isStatic() guard and a regression test.

Minor: it would be good to add a test for a const pointer member (int* const p;).

🤖 Generated with Claude Code

[danmar]

please check the results here:
http://ec2-16-170-140-253.eu-north-1.compute.amazonaws.com/