@Nullable private PyType replaceSelf( @Nullable PyType returnType, @Nullable PyExpression receiver, @NotNull TypeEvalContext context) { if (receiver != null) { // TODO: Currently we substitute only simple subclass types, but we could handle union and // collection types as well if (returnType instanceof PyClassType) { final PyClassType returnClassType = (PyClassType) returnType; if (returnClassType.getPyClass() == getContainingClass()) { final PyType receiverType = context.getType(receiver); if (receiverType instanceof PyClassType && PyTypeChecker.match(returnType, receiverType, context)) { return returnClassType.isDefinition() ? receiverType : ((PyClassType) receiverType).toInstance(); } } } } return returnType; }