In file included from /usr/include/c++/9/bits/char_traits.h:39,
                 from /usr/include/c++/9/ios:40,
                 from /usr/include/c++/9/istream:38,
                 from /usr/include/c++/9/sstream:38,
                 from /usr/include/c++/9/complex:45,
                 from /usr/include/c++/9/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:54,
                 from foo.cc:1:
/usr/include/c++/9/bits/stl_algobase.h: In instantiation of 'const _Tp& std::max(const _Tp&, const _Tp&, _Compare) [with _Tp = long long int; _Compare = long long int]':
foo.cc:14:58:   required from here
/usr/include/c++/9/bits/stl_algobase.h:271:17: error: '__comp' cannot be used as a function
  271 |       if (__comp(__a, __b))
      |           ~~~~~~^~~~~~~~~~

Found 20 testcases.
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