959e627208
The scoping rules around %template have been specified and enforced.
The %template directive for a class template is the equivalent to an
explicit instantiation of a C++ class template. The scope for a valid
%template instantiation is now the same as the scope required for a
valid explicit instantiation of a C++ template. A definition of the
template for the explicit instantiation must be in scope where the
instantiation is declared and must not be enclosed within a different
namespace.
For example, a few %template and explicit instantiations of std::vector
are shown below:
// valid
namespace std {
%template(vin) vector<int>;
template class vector<int>;
}
// valid
using namespace std;
%template(vin) vector<int>;
template class vector<int>;
// valid
using std::vector;
%template(vin) vector<int>;
template class vector<int>;
// ill-formed
namespace unrelated {
using std::vector;
%template(vin) vector<int>;
template class vector<int>;
}
// ill-formed
namespace unrelated {
using namespace std;
%template(vin) vector<int>;
template class vector<int>;
}
// ill-formed
namespace unrelated {
namespace std {
%template(vin) vector<int>;
template class vector<int>;
}
}
// ill-formed
namespace unrelated {
%template(vin) std::vector<int>;
template class std::vector<int>;
}
When the scope is incorrect, an error now occurs such as:
cpp_template_scope.i:34: Error: 'vector' resolves to 'std::vector' and
was incorrectly instantiated in scope 'unrelated' instead of within scope 'std'.
Previously SWIG accepted the ill-formed examples above but this led to
numerous subtle template scope problems especially in the presence of
using declarations and using directives as well as with %feature and %typemap.
Actually, a valid instantiation is one which conforms to the C++03
standard as C++11 made a change to disallow using declarations and
using directives to find a template.
// valid C++03, ill-formed C++11
using std::vector;
template class vector<int>;
Similar fixes for defining classes using forward class references have
also been put in place. For example:
namespace Space1 {
struct A;
}
namespace Space2 {
struct Space1::A {
void x();
}
}
will now error out with:
cpp_class_definition.i:5: Error: 'Space1::A' resolves to 'Space1::A' and
was incorrectly instantiated in scope 'Space2' instead of within scope 'Space1'.
57 lines
892 B
OpenEdge ABL
57 lines
892 B
OpenEdge ABL
%module xxx
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namespace std {
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template<typename T> class vector {};
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}
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struct S1 {};
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struct S2 {};
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struct S3 {};
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struct S4 {};
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struct S5 {};
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struct S6 {};
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struct S7 {};
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// valid
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namespace std {
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%template(vi1) vector<S1>;
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template class vector<S1>;
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}
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// valid
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using namespace std;
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%template(vi2) vector<S2>;
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template class vector<S2>;
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// valid
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using std::vector;
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%template(vi3) vector<S3>;
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template class vector<S3>;
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// ill-formed
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namespace unrelated {
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using std::vector;
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%template(vi4) vector<S4>;
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template class vector<S4>;
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}
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// ill-formed
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namespace unrelated {
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using namespace std;
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%template(vi5) vector<S5>;
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template class vector<S5>;
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}
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// ill-formed
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namespace unrelated {
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namespace std {
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%template(vi6) vector<S6>;
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template class vector<S6>;
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}
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}
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// ill-formed
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namespace unrelated {
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%template(vi7) std::vector<S7>;
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template class std::vector<S7>;
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}
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