protected override IEnumerable <SyntaxNode> SelectMatchingDeclarations(
SyntaxNodeAndSemanticModel <TypeBlockSyntax> container, ISet <SyntaxKind> kinds) =>
container.SyntaxNode.DescendantNodes(IsNodeContainerTypeDeclaration)
.Where(node => kinds.Contains(node.Kind()));
protected abstract IEnumerable <SyntaxNode> SelectMatchingDeclarations(
SyntaxNodeAndSemanticModel <TOwnerOfSubnodes> container,
ISet <TSyntaxKind> kinds);