Add attribute to support inline namespaces in C++/CLI.

[tgani-msft]

A new assembly-scope custom attribute

[CppInlineNamespace(string dottedName)]

has been added to implement inline namespaces in C++/CLI. For every
inline namespace encountered in a translation unit, the C++ compiler
will emit this attribute with the fully scoped name, in CLR dotted
form, as the argument for the attribute.

[jkoritzinsky]

cc: @terrajobst

[terrajobst]

@tgani-msft @jkoritzinsky

Please file an issue with the proposed API plus some more explanation. Also, it would help to see some C++ sample code to understand what inline namespace is.

[tgani-msft]

Filed #783

[tgani-msft]

@jkoritzinsky looks like I have to add the attribute class in a reference assembly as well? Where?

[terrajobst]

Filed #783

Thanks. I've added some questions there.

[tgani-msft]

@jkoritzinsky I would appreciate help getting this through. I mis-remembered that this had been merged but this is blocked due to failures like this:

.packages\microsoft.dotnet.apicompat\5.0.0-beta.19608.1\build\Microsoft.DotNet.ApiCompat.targets(143,5): error : TypesMustExist : Type 'System.Runtime.CompilerServices.CppInlineNamespaceAttribute' does not exist in the reference but it does exist in the implementation.

Where/how does this need to be fixed? Thanks.

[jkoritzinsky]

You'll need to also add a definition of the type in src\libraries\System.Runtime.CompilerServices.VisualC\src\System\Runtime\CompilerServices\Attributes.cs

[tgani-msft]

@jkoritzinsky I already have that change (actually the only change I have in this PR). I think it also needs to be duplicated somewhere else. I would have assumed that the refs were generated automatically?

[jkoritzinsky]

Sorry swap the last src in that path with ref. That’s the file you need to edit.

[tgani-msft]

Yes, thanks.

[dnfclas]

All CLA requirements met.