Google Mock - using ::testing::An()

I receive a compilation error while using the following Google Mock declaration:

EXPECT_CALL(some_object, someFunction(1,An<AStructIDefined>()))
    .Times(2);

The error is:

1>ClCompile:
1>  TestMyClass.cpp
1>TestMyClass.cpp(189): error C2664: 'mynamespace::MockMyClassClient::gmock_someFunction' : cannot convert parameter 2 from 'testing::Matcher<T>' to 'const testing::Matcher<T> &'
1>          with
1>          [
1>              T=mynamespace::AStructIDefined
1>          ]
1>          and
1>          [
1>              T=const mynamespace::AStructIDefined &
1>          ]
1>          Reason: cannot convert from 'testing::Matcher<T>' to 'const testing::Matcher<T>'
1>          with
1>          [
1>              T=mynamespace::AStructIDefined
1>          ]
1>          and
1>          [
1>              T=const mynamespace::AStructIDefined &
1>          ]
1>          No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

What am I doing wrong?

UPDATES:

I am using VS2010.

The declaration of someFunction is:

virtual void someFunction( long long ll, const AStructIDefined& a_struct);

An() is a Google Mock wildcard matcher with the following definition:

// Creates a matcher that matches any value of the given type T.
template <typename T>
inline Matcher<T> An() { return A<T>(); }

A simplified yet representative version of the struct is:

namespace mynamespace {

class ABaseCLass
{
public:
    virtual ~ABaseCLass(){};
    virtual bool isValid() const = 0;
};

struct AStructIDefined : public ABaseCLass
{
开发者_如何转开发public:
    OrderStatusReport(SomeEnum1 e_, int i_, double d_);

    SomeEnum1 e;
    int i;
    double d;

    const std::string toString() const;
    bool isSane() const;
    bool operator== (const SomeEnum1& ref_) const;
    double getD() const;
    int getI() const;
    bool isCondition() const;
};

} // namespace mynamespace

The solution was to change the declaration from:

EXPECT_CALL(some_object, someFunction(1,An<AStructIDefined>()))
    .Times(2);

to

EXPECT_CALL(some_object, someFunction(1,An<const AStructIDefined &>()))
    .Times(2);

C++ implicitly casts const and reference & on function parameters, but google mock's declaration seems to require the type appearing in the function's signature and not the type submitted as a parameter to the function.