CS1584/CS1658 considers XML comment references to be declarations. This causes constructed generic references to be considered invalid.

[otac0n]

The type syntax is being validated as a declaration rather than a reference, preventing a constructed type from being used:

[daiplusplus]

XML Doc's cref has never supported type parameter arguments though; it's a longstanding request:

• CS1584+CS1658/CS0081 when using constructed generic types in XML comments csharplang#8986
• CS1584 and CS1658 on cref with generic type of generic type DotNetAnalyzers/StyleCopAnalyzers#2304

It's not just XML Docs where this is a problem though: the BannedApiAnalyzers uses the same syntax (and limitations...) too:

• BannedApiAnalyzer – Generics Instantiation roslyn#81081