class C<TOuter>
			{
				/// <summary>
				/// <remarks>
				/// <see cref="CRequires{TOuter}.IsIt"/>  This causes NullRef
				/// </remarks>
				/// </summary>
				static CRequires<TOuter> Value => throw new Exception();
			}

                        // This produces a warning as it should
			class CRequires<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)] TInner> { public static bool IsIt => false; }

The NullRef happens because we try to validate the generic instantiation (matching annotations), and in this case it leads to us trying to produce a warning on the cref. But the type argument given to us by Roslyn doesn't have a containing type (not sure why), and so we fail to produce a display name for it (NullRef).

The fix is to actually disallow analysis of any symbol inside a cref, we don't want to produce warnings for that. We already did that for some crefs, but not all.