False positive for clang static analyzer checker optin.cplusplus.UninitializedObject

[llvmbot]

Bugzilla Link	51316
Version	trunk
OS	Linux
Reporter	LLVM Bugzilla Contributor
CC	@DougGregor,@zygoloid

Extended Description

Checker UninitializedObject is enable by default in clang-tidy and reports some false positives. Tests case(UninitializedObjectChecker_false_positive.cpp) :

struct Operand_ { int e; int a[2]; };

class b : Operand { public: b() : Operand{ 1, { 2, 3 }} {} };

void c() { b(); }

---

It returns wrong warning:

---

UninitializedObjectChecker_falsepositive.cpp:9:17: warning: 1 uninitialized field at the end of the constructor call [optin.cplusplus.UninitializedObject] b() : Operand{ 1, { 2, 3 }} {} ^~~~~~ UninitializedObjectChecker_falsepositive.cpp:3:7: note: uninitialized field 'this->Operand::e' int e; ^ 1 warning generated.

Arguments for clang-12 or clangs-13 in trunk:

---

clang-12 -c UninitializedObjectChecker_false_positive.cpp -Xclang -analyzer-checker=optin.cplusplus.UninitializedObject -Xclang -analyze

---

[tiagomacarios]

I think I just hit the same issue with a simpler repro.

Initializing S with {} triggers the false positive. () works fine.

https://godbolt.org/z/3rTdacqo7

struct S {
    int i1 = 0;
};

struct K : S {
    int ii1 = 0;
    K() : S() {}
    // K() : S{} {}
};

void _() {
    K k;
}