| Issue |
120863
|
| Summary |
[clang-tidy] Check request: don't capture `this` by a field of default copyable class
|
| Labels |
clang-tidy
|
| Assignees |
|
| Reporter |
denzor200
|
Assume the user defined class:
```
struct A {
std::string content;
std::function<void()> captured;
A() {
captured =
[this]() { // INCORRECT
perform();
};
}
void perform() { std::cout << content << std::endl; }
};
```
Since it's copy constructor was generated by the compiler, it's behaviour might be unexpected for some user and even can produce a crash with SIGSEGV:
```
A a;
a.content = "Hello world";
a.captured();
A a1 = a;
a1.content = "Test";
a1.captured(); // will print "Hello world" which might be unexpected
```
```
auto a = std::make_unique<A>();
a->content = "Hello world";
a->captured();
auto b = std::make_unique<A>(*a);
a.reset();
b->content = "Ooooups!";
b->captured(); // UB
```
The way to fix it is to provide manually written copy constructor and assignment operator:
```
A(const A& oth)
: content(oth.content)
, captured([this](){perform();}) {}
A& operator=(const A& oth) {
if (this != &oth) {
content = oth.content;
captured = [this](){perform();};
}
}
```
Making you class noncopyable also protect you from the bug:
```
A(const A& oth) = delete;
A& operator=(const A& oth) = delete;
```
But before you fix it you must discover it in the code, so the clang-tidy check in bugprone section would be nice addition.
![]()
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
