src/third_party/llvm-project/clang/test/SemaCXX/namespace-alias.cpp

// RUN: %clang_cc1 -fsyntax-only -verify %s

namespace N { struct X { }; };

namespace A = N;

int B; // expected-note {{previous definition is here}}
namespace B = N; // expected-error {{redefinition of 'B' as different kind of symbol}}

namespace C { } // expected-note {{previous definition is here}}
namespace C = N; // expected-error {{redefinition of 'C'}}

int i;
namespace D =
i; // expected-error {{expected namespace name}}

namespace E1 = N::
Foo; // expected-error {{expected namespace name}}
namespace E2 = N::
X; // expected-error {{expected namespace name}}

namespace F {
  namespace A { namespace B { } } // expected-note {{candidate found by name lookup is 'F::A::B'}}
  namespace B { } // expected-note {{candidate found by name lookup is 'F::B'}}
  using namespace A;
  namespace D = B; // expected-error {{reference to 'B' is ambiguous}}
}

namespace G { 
  namespace B = N;
}

namespace H {
  namespace A1 { }
  namespace A2 { }

  // These all point to A1.
  namespace B = A1;
  namespace B = A1;
  namespace C = B;
  namespace B = C; // expected-note {{previously defined as an alias for 'A1'}}

  namespace B = A2; // expected-error {{redefinition of 'B' as an alias for a different namespace}}
}

namespace I { 
  namespace A1 { int i; }
  
  namespace A2 = A1;
}

int f() {
  return I::A2::i;
}

namespace J {
  namespace A { 
    namespace B { void func (); }
  }

  namespace C = A;

  using namespace C::B;

  void g() {
    func();
  }
}

namespace K {
  namespace KA { void func(); }

  void f() {
    namespace KB = KA;
    KB::func();
  }

  template <class T> void g() {
    namespace KC = KA;
    KC::func();
  }
  template void g<int>();
  template void g<long>();

  void h() {
    KB::func(); // expected-error {{undeclared identifier 'KB'}}
    KC::func(); // expected-error {{undeclared identifier 'KC'}}
  }
}

namespace {
  class C1;
}
namespace {
  class C1;
}
C1 *pc1 = 0;

namespace N {
  namespace {
    class C2;
  }
}
namespace N {
  namespace {
    class C2;
  }
}
N::C2 *pc2 = 0;

// PR6341
namespace A = N;
namespace N { }
namespace A = N;

A::X nx;

namespace PR7014 {
  namespace X
  {
    namespace Y {}
  }

  using namespace X;

  namespace Y = X::Y;
}

namespace PR25731 {
  void f() {
    namespace X = PR25731;
    namespace X = PR25731;
    X::f();
  }
}

namespace MultipleUnambiguousLookupResults {
  namespace A { int y; }
  namespace B {
    namespace X { int x; }
    namespace Y = A;
    namespace Z = A; // expected-note {{candidate}}
  }
  namespace C {
    namespace X = B::X;
    namespace Y = A;
    namespace Z = X; // expected-note {{candidate}}
  }
  using namespace B;
  using namespace C;
  int x1 = X::x; // ok, unambiguous
  int y1 = Y::y; // ok, unambiguous
  int z1 = Z::x; // expected-error {{ambiguous}}

  namespace X = C::X;
  namespace Y = A;
  int x2 = X::x; // ok, unambiguous
  int y2 = Y::y; // ok, unambiguous
}

namespace RedeclOfNonNamespace {
  int a; // expected-note {{previous}}
  namespace X { int b; }
  using X::b; // expected-note {{previous}}
  namespace c {} // expected-note {{previous}}

  namespace a = X; // expected-error {{different kind}}
  namespace b = X; // expected-error {{different kind}}
  namespace c = X; // expected-error-re {{redefinition of 'c'{{$}}}}
}