$ cat makeuniquetest.cpp 
#include <memory>
int main()
{
    auto p = std::unique_ptr<int>{new int()};
    p.reset(new int());
}

clang-tidy warns about line 4, but not line 5:
 
$ clang-tidy makeuniquetest.cpp -checks=-*,modernize-make-unique -- -std=c++14
1 warning generated.
/makeuniquetest.cpp:4:14: warning: use std::make_unique instead [modernize-make-unique]
    auto p = std::unique_ptr<int>{new int()};
             ^
             std::make_unique    (        )

Expected result after applying fixes:

#include <memory>
int main()
{
    auto p = std::make_unique<int>();
    p = std::make_unique<int>();
}