Allow using a GUID value directly when declaring a COM interface.

[Benkol003]

Suggestion

See Benkol003@1cb1c57
This makes things tidier when bulk declaring COM interfaces that have a common format that could be written by a const fn, e.g. for 7zip i form interface GUID's as follows:

pub const fn z7_iface_iid(group: u8,id: u8) -> GUID {
    GUID { 
        data1: 0x23170F69, 
        data2: 0x40C1, 
        data3: 0x278A, 
        data4: [0x00,0x00,0x00,group,0x00,id,0x00,0x00] 
    }
}

#[interface(z7_iface_iid(0x6,0x20))]
unsafe trait IArchiveOpenCallback: Iunknown {
//methods...
}

[kennykerr]

Seems reasonable enough. Did you have a compelling use case? This is not the typical way to declare/generate GUIDs but I know it has been done this way in some cases in the Windows SDK.

[Benkol003]

Hi, yes I'm writing bindings for the 7zip LZMA SDK which structures it's IID's off common base GUID formats like the example above (rather than using a randomly generated IID per interface), documented here