__declspec properties outside of class members do not work as expected

[kodenamekrak]

As shown in the example below, the properties return unexpected results when used outside of class members.
Although, according to Microsoft's specification, they shouldnt be allowed outside of members and should cause error C3065

https://godbolt.org/z/jqe59vW85

#include <cstdio>

struct Color {
    float r, g, b, a;
};

struct Test {
    Color get_value() {
        return Color{1.0f, 0.5f, 0.5f, 1.0f};
    }
    __declspec(property(get=get_value)) Color value;
};

Color get_value() {
    return Color{1.0f, 0.5f, 0.5f, 1.0f};
}
__declspec(property(get=get_value)) Color value;

int main() {
    Test t;

    auto color2 = t.value;
	printf("%f, %f, %f, %f\n", color2.r, color2.g, color2.b, color2.a);

    // returns empty ?
    auto color3 = value;
	printf("%f, %f, %f, %f\n", color3.r, color3.g, color3.b, color3.a);

    auto color4 = get_value();
	printf("%f, %f, %f, %f\n", color4.r, color4.g, color4.b, color4.a);

    return 0;
}

1.000000, 0.500000, 0.500000, 1.000000
0.000000, 0.000000, 0.000000, 0.000000
1.000000, 0.500000, 0.500000, 1.000000

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: None (kodenamekrak)

As shown in the example below, the properties return unexpected results when used outside of class members. Although, according to [Microsoft's specification](https://learn.microsoft.com/en-us/cpp/cpp/property-cpp?view=msvc-170), they shouldnt be allowed outside of members and should cause [error C3065](https://learn.microsoft.com/en-us/cpp/error-messages/compiler-errors-2/compiler-error-c3065?view=msvc-170)

https://godbolt.org/z/jqe59vW85

#include <cstdio>

struct Color {
    float r, g, b, a;
};

struct Test {
    Color get_value() {
        return Color{1.0f, 0.5f, 0.5f, 1.0f};
    }
    __declspec(property(get=get_value)) Color value;
};

Color get_value() {
    return Color{1.0f, 0.5f, 0.5f, 1.0f};
}
__declspec(property(get=get_value)) Color value;

int main() {
    Test t;

    auto color2 = t.value;
	printf("%f, %f, %f, %f\n", color2.r, color2.g, color2.b, color2.a);

    // returns empty ?
    auto color3 = value;
	printf("%f, %f, %f, %f\n", color3.r, color3.g, color3.b, color3.a);

    auto color4 = get_value();
	printf("%f, %f, %f, %f\n", color4.r, color4.g, color4.b, color4.a);

    return 0;
}

1.000000, 0.500000, 0.500000, 1.000000
0.000000, 0.000000, 0.000000, 0.000000
1.000000, 0.500000, 0.500000, 1.000000

[shafik]

CC @AaronBallman

[AaronBallman]

Different godbolt link: https://godbolt.org/z/eEjTEE6f1

Clang should reject this, same as MSVC.