Viewing file:  forward-inner.C (2.4 KB) -rw-r--r--
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// Check that the compiler warns about inner-style forward declarations in
// contexts where they're not actually illegal, but merely useless.
// Verify warnings for and within classes, and by extension, struct and union.
class C1;
class C1::C2; // { dg-error "incomplete" }
class C1::C2::C3; // { dg-error "has not been declared" }
class C1 {
public:
class C2;
class C2::C3; // { dg-error "incomplete" }
class C2 {
public:
class C3;
class C3 { };
class C3;
};
class C2;
class C2::C3; // { dg-warning "declaration 'class C1::C2::C3' does not declare anything" }
};
class C1;
class C1::C2; // { dg-warning "declaration 'class C1::C2' does not declare anything" }
class C1::C2::C3; // { dg-warning "declaration 'class C1::C2::C3' does not declare anything" }
// Verify warnings for namespace scopes.
class N1::C4; // { dg-error "has not been declared" }
class N1::N2::C5; // { dg-error "has not been declared" }
namespace N1 {
class C4;
class C4 { };
class C4;
class N2::C5; // { dg-error "has not been declared" }
namespace N2 {
class C5;
class C5 { };
class C5;
}
class N2::C5; // { dg-warning "declaration 'class N1::N2::C5' does not declare anything" }
}
class N1::C4; // { dg-warning "declaration 'class N1::C4' does not declare anything" }
class N1::N2::C5; // { dg-warning "declaration 'class N1::N2::C5' does not declare anything" }
// Verify that using declarations related to namespaces don't generate a
// warning.
using namespace N1;
using namespace N1::N2;
namespace N3 {
using N1::C4; // Valid using declaration, no warning
using N1::N2::C5; // Valid using declaration, no warning
}
// Verify that explicit template instantiations, easy to confuse with
// forward declarations, don't generate a warning.
template<class C>
class TC6 {
public:
class TC7 { };
};
template class TC6<int>::TC7; // Valid explicit instantiation, no warning
// Verify that friend declarations, also easy to confuse with forward
// declarations, are similarly not warned about.
class C8 {
public:
class C9 { };
};
class C10 {
public:
friend class C8::C9; // Valid friend declaration, no warning
};
#if __cplusplus >= 201103L
// Verify that alias-declarations using an elaborated-type-specifier and
// nested-name-specifier are not warned about (PR c++/66159).
struct C11;
using A1 = struct ::C11; // Valid alias-decl, no warning
#endif
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