llvm/clang/test/CXX/dcl.decl/dcl.init/p6.cpp

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

// FIXME: Very incomplete!

// If a program calls for the default initialization of an object of a
// const-qualified type T, T shall be a class type with a
// user-provided default constructor, except if T has no uninitialized fields.
struct MakeNonPOD { MakeNonPOD(); };
struct NoUserDefault : public MakeNonPOD { int field; };
struct HasUserDefault { HasUserDefault(); };

void test_const_default_init() {
  const NoUserDefault x1; // expected-error{{default initialization of an object of const type 'const NoUserDefault' without a user-provided default constructor}}
  const HasUserDefault x2;
  const int x3; // expected-error{{default initialization of an object of const type 'const int'}}
}

struct s0 { int field; };
struct s1 { static const s0 foo; };
const struct s0 s1::foo; // expected-error{{default initialization of an object of const type 'const struct s0' without a user-provided default constructor}}

template<typename T>
struct s2 {
  static const s0 foo;
};

template<> const struct s0 s2<int>::foo; // okay