Clang's lifetime profile will catch the first example:

    <source>:8:16: warning: passing a dangling pointer as argument [-Wlifetime]
      std::cout << sv;
                   ^

    <source>:7:38: note: temporary was destroyed at the end of the full expression
      std::string_view sv = s + "World\n";
                                         ^

And cppcheck will catch the second example:

    <source>:7:12: warning: Returning lambda that captures local variable 'x' that will be invalid when returning. [returnDanglingLifetime]
        return [&]() { return *x; };
               ^
    <source>:7:28: note: Lambda captures variable by reference here.
        return [&]() { return *x; };
                               ^
    <source>:6:49: note: Variable created here.
    std::function<int(void)> f(std::shared_ptr<int> x) {
                                                    ^
    <source>:7:12: note: Returning lambda that captures local variable 'x' that will be invalid when returning.
        return [&]() { return *x; };
               ^

Cppcheck could probably catch all the examples, but it needs to be updated to understand the newer classes in C++.

Others disagree, but I suggest that someone could make such a linter. As others point out, the Core Guidelines "lifetime profile checker"[1] is designed to be an advanced static analyzer that restricts how many C++ elements can be used. It's not finished yet, and the current version is not designed to achieve complete memory safety (and doesn't address data race safety). Whether or not subsequent versions could match the full safety enforcement of Rust's compiler seems to be a matter of some debate.

But there is an alternative/complementary approach, which is to simply avoid potentially unsafe C++ elements, like pointers/references, arrays, std::string_views, std::threads, etc., substituting them with safe, largely compatible replacements[2]. This approach has the benefit that an associated safety-enforcing "linter" would not impose the same kinds of "severe" usage restrictions that the lifetime profile checker (or, say, the Rust compiler) does.

[1] https://devblogs.microsoft.com/cppblog/lifetime-profile-upda...

[2] https://github.com/duneroadrunner/SaferCPlusPlus

edit: grammar

The Core Guidelines are an attempt at this, but it’s not fully safe. Safer, which matters! But not safe.

There isn’t really any useful safe subset of C++. If there were, Rust may never have been created in the first place.

The answer is essentially no, at least if you're seeking substantial levels of assurance or safety. Even the C++ Core Guidelines effort, https://github.com/isocpp/CppCoreGuidelines which is the closest thing to what you describe and is driven by influential members of the ISO C++ community including B. Stroustrup, does not claim that they'll be able to make C++ memory safe.