psalm/src/Psalm/Internal/Stubs/CoreImmutableClasses.phpstub

<?php

/**
 * @psalm-immutable
 */
class DateTimeImmutable implements DateTimeInterface
{
    public function __construct(string $time = "now", DateTimeZone $tz = null) {}
}

/**
 * @psalm-immutable
 */
class DateTimeZone
{
    public function __construct(string $tz) {}
}

interface Throwable
{
    /**
     * @psalm-mutation-free
     */
    public final function getMessage() : string {}
}

class Exception implements Throwable
{
    /**
     * @psalm-external-mutation-free
     * @param string $message
     * @param int $code
     * @param Throwable $previous
     */
    public function __construct($message = "", $code = 0, Throwable $previous = null) { }

    /**
     * @psalm-mutation-free
     */
    public final function getMessage() : string {}

    /**
     * @psalm-mutation-free
     * @return int|string
     */
    public final function getCode(){}

    /**
     * @psalm-mutation-free
     * @return string
     */
    public final function getFile(){}

    /**
     * @psalm-mutation-free
     * @return int
     */
    public final function getLine(){}
}