False positive unusedPrivateFunction when using trailing return type

[Stefan Büttner]

Hey there,

I stumbled over this behavior which seems weird and a false positive:

#include <string>

class foobar
{
public:
    [[nodiscard]] std::string const& foo() const noexcept { return _a; }
    [[nodiscard]] auto bar() const noexcept -> std::string const& { return _a; }

private:
    std::string _a{};
};

>$ cppcheck --version
Cppcheck 2.14.0
$> cppcheck --enable=performance foobar.cpp
Checking foobar.cpp ...
foobar.cpp:6:24: performance: Function 'bar()' should return member '_a' by const reference. [returnByReference]
    [[nodiscard]] auto bar() const noexcept -> std::string const& { return _a; }
                       ^

Can someone confirm or am I missing something?

Cheers,
Stefan

[Stefan Büttner]

As you can see by the title, I found the another, related thread, wanted to name this one similar but forgot to change the title appropriately 🤦‍♂️
Maybe you can still do that.

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/12962