CODEWITHSUNDEEP
compiler-warningsclang++
user2052436
user2052436

Reputation: 4765

Clang erroneous unneeded-internal-declaration warning?

clang++ (17.0.1) gives a warning for this code:

#include <iostream>

namespace {
    void fun ()
    {
        std::cout << "fun\n";
    }
} // namespace

template<class T>
void tfun (T)
{
    fun();
}

template<> void tfun (int);

The warning goes away if fun is not inside an anonymous namespace.

Is this a compiler bug?

See godbolt

Upvotes: 3

Views: 176

Answers (1)

Sergey Krivohatskiy
Sergey Krivohatskiy

Reputation: 190

This is an annoying error, but it is still an error according to the compiler (and not a compiler bug IMHO).

From the compiler POV, if the template function tfun is not instanciated, then the function fun is not used anywhere. Like tfun is not even there.

One of the possible fixes is to make fun templated and instanciate it only if tfun is instanciated. This is not the "fix" I like, but I can not come up with anything better.

Here is a compilable block of code:

#include <iostream>

namespace {
    template<class T>
    void fun ()
    {
        std::cout << "fun\n";
    }
}

template<class T>
void tfun (T)
{
    fun<T>();
}

Upvotes: 0

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