Macro implemented as a generic type can't be found by client

Using Swift
,
1

I have a use case where I implement macro as generic type. The macro read data from a config module. These data have different variations and all conform to a protocol. That's why I implement it as a generic type.

At first I had the following in macro's compiler plugin file:

@main
struct macroPlugin: CompilerPlugin {
    let providingMacros: [Macro.Type] = [
        MyGenericMacro<FooConfig>.self,
    ]
}

and the following in macro interface file:

@attached(member, names: arbitrary)
public macro Foo() = #externalMacro(module: "myGenericMacroImpl", type: "MyGenericMacro<FooConfig>")

But compiler failed to find the macro in client code.

Then I created a type alias in macro pacakge:

public typealias FooMacro = MyGenericMacro<FooConfig>

and modified the above code to use the alias name. But client code still failed to find it.

Finally I had to create a wrapper struct and it worked this time.

public struct FooMacro: MemberMacro {
    public static func expansion(
      of node: AttributeSyntax,
      providingMembersOf declaration: some DeclGroupSyntax,
      in context: some MacroExpansionContext
    ) throws -> [DeclSyntax] {
        try MyGenericMacro<FooConfig>.expansion(of: node, providingMembersOf: declaration, in: context)
    }
}

I wonder if anyone saw similar issues? It seems a bug to me (though I have a hard time understanding why type alias doesn't work around it). Since this is probably just a corner case, I didn't create a bug report, but think it might be worth mentioning it here.