From b4b2bc66c7478e39f427114223ef7394f7b11250 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Sun, 31 Jul 2022 18:02:30 +0200
Subject: [PATCH 01/22] Added better stubs for `DateTimeImmutable`,
 highlighting how the constructor is **NOT** immutable

`DateTimeImmutable` is **almost** immutable: `DateTimeImmutable::__construct()` is in fact not a pure
method, since `new DateTimeImmutable('now')` produces a different value at each instantiation (by design).

This change makes sure that `DateTimeImmutable` loses its `@psalm-immutable` class-level marker,
preventing downstream misuse of the constructor inside otherwise referentially transparent code.

Note: only pure methods are stubbed here: all other methods declared by `DateTimeImmutable` (parent interface)
are NOT present here, and are either inferred from runtime reflection, or `CallMap*.php` definitions.

Methods are sorted in the order defined by reflection on PHP 8.1.8, at the time of writing this ( https://3v4l.org/3TGg8 ).

Following simplistic snippet was used to infer the current signature:

```php
<?php

$c = new \ReflectionClass(\DateTimeImmutable::class);

$methods = array_map(function ($m) {
    return $m->getName()
        . '(' . implode(',', array_map(function ($p) {
            return $p->getType()
                . ' $' . $p->getName()
                . ($p->isOptional() ? ' = ' . var_export($p->getDefaultValue(), true) : '');
        }, $m->getParameters())) . ')' . ($m->getReturnType() ? (': ' . $m->getReturnType()) : '');
}, $c->getMethods());

$properties = array_map(function ($m) {
    return $m->getName();
}, $c->getProperties());

var_dump($methods, $properties);
```
---
 stubs/CoreImmutableClasses.phpstub | 101 ++++++++++++++++++++++++++++-
 1 file changed, 98 insertions(+), 3 deletions(-)

diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index 405f89b43cd..325a1c2a2ce 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -1,11 +1,106 @@
 <?php
 
-/**
- * @psalm-immutable
- */
 class DateTimeImmutable implements DateTimeInterface
 {
     public function __construct(string $datetime = "now", DateTimeZone $timezone = null) {}
+
+    /**
+     * @psalm-pure
+     * @return static|false
+     */
+    public static function createFromFormat(string $format, string $datetime, ?DateTimeZone $timezone = null) {}
+
+    /**
+     * @psalm-pure
+     * @param string $format
+     * @return string
+     */
+    public function format($format) {}
+
+    /**
+     * @psalm-pure
+     * @return DateTimeZone
+     */
+    public function getTimezone() {}
+
+    /**
+     * @psalm-pure
+     * @return int
+     */
+    public function getOffset() {}
+
+    /**
+     * @psalm-pure
+     * @return int
+     */
+    public function getTimestamp() {}
+
+    /**
+     * @psalm-pure
+     * @param bool $absolute
+     * @return DateInterval
+     */
+    public function diff(DateTimeInterface $targetObject, $absolute = false) {}
+
+    /**
+     * @psalm-pure
+     * @return static
+     */
+    public function modify(string $modifier) {}
+
+    /**
+     * @psalm-pure
+     * @return static
+     */
+    public function add(DateInterval $interval) {}
+
+    /**
+     * @psalm-pure
+     * @return static
+     */
+    public function sub(DateInterval $interval) {}
+
+    /**
+     * @psalm-pure
+     * @return static|false
+     */
+    public function setTimezone(DateTimeZone $timezone) {}
+
+    /**
+     * @psalm-pure
+     * @return static|false
+     */
+    public function setTime(int $hour, int $minute, int $second = 0, int $microsecond = 0) {}
+
+    /**
+     * @psalm-pure
+     * @return static|false
+     */
+    public function setDate(int $year, int $month, int $day) {}
+
+    /**
+     * @psalm-pure
+     * @return static|false
+     */
+    public function setISODate(int $year, int $week, int $dayOfWeek = 1) {}
+
+    /**
+     * @psalm-pure
+     * @return static|false
+     */
+    public function setTimestamp(int $unixtimestamp) {}
+
+    /**
+     * @psalm-pure
+     * @return static
+     */
+    public static function createFromMutable(DateTime $object) {}
+
+    /**
+     * @psalm-pure
+     * @return self
+     */
+    public static function createFromInterface(DateTimeInterface $object) {}
 }
 
 /**

From dcaf610b0a032a9fffeb6ba289b261e1c63da6a5 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Sun, 31 Jul 2022 18:08:01 +0200
Subject: [PATCH 02/22] Removed `@psalm-immutable` marked from `MyDate`
 extending `DateTimeImmutable`

`DateTimeImmutable` is not really immutable, therefore this marker was wrong upfront
---
 tests/MethodCallTest.php | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/MethodCallTest.php b/tests/MethodCallTest.php
index 843cce11941..956536988a1 100644
--- a/tests/MethodCallTest.php
+++ b/tests/MethodCallTest.php
@@ -264,7 +264,6 @@ public static function main(): void {
             ],
             'dateTimeImmutableStatic' => [
                 '<?php
-                    /** @psalm-immutable */
                     final class MyDate extends DateTimeImmutable {}
 
                     $today = new MyDate();

From c205d652d1e9afd9510db59e72c3fd0a4a093b3d Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Sun, 31 Jul 2022 18:12:07 +0200
Subject: [PATCH 03/22] `DateTimeImmutable#sub()` always returns another
 `static` instance, never `false`

---
 tests/MethodCallTest.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/MethodCallTest.php b/tests/MethodCallTest.php
index 956536988a1..76c033f56f5 100644
--- a/tests/MethodCallTest.php
+++ b/tests/MethodCallTest.php
@@ -271,7 +271,7 @@ final class MyDate extends DateTimeImmutable {}
 
                     $b = (new DateTimeImmutable())->modify("+3 hours");',
                 'assertions' => [
-                    '$yesterday' => 'MyDate|false',
+                    '$yesterday' => 'MyDate',
                     '$b' => 'DateTimeImmutable',
                 ],
             ],

From 68978b9e19c70036e6e5077a6234af513afdc77f Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Mon, 1 Aug 2022 10:08:35 +0200
Subject: [PATCH 04/22] s/psalm-pure/psalm-mutation-free, since
 psalm-mutation-free is safer to use

Ref: https://github.com/vimeo/psalm/pull/8350/files/c205d652d1e9afd9510db59e72c3fd0a4a093b3d#r934032422

The idea is that `@psalm-pure` disallows `$this` usage in child classes,
which is not wanted, while `@psalm-mutation-free` allows it.

By using `@psalm-mutation-free`, we don't completely destroy inheritance
use-cases based on internal (immutable) state.
---
 stubs/CoreImmutableClasses.phpstub | 32 +++++++++++++++---------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index 325a1c2a2ce..2d6555c3df2 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -5,99 +5,99 @@ class DateTimeImmutable implements DateTimeInterface
     public function __construct(string $datetime = "now", DateTimeZone $timezone = null) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static|false
      */
     public static function createFromFormat(string $format, string $datetime, ?DateTimeZone $timezone = null) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @param string $format
      * @return string
      */
     public function format($format) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return DateTimeZone
      */
     public function getTimezone() {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return int
      */
     public function getOffset() {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return int
      */
     public function getTimestamp() {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @param bool $absolute
      * @return DateInterval
      */
     public function diff(DateTimeInterface $targetObject, $absolute = false) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static
      */
     public function modify(string $modifier) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static
      */
     public function add(DateInterval $interval) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static
      */
     public function sub(DateInterval $interval) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static|false
      */
     public function setTimezone(DateTimeZone $timezone) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static|false
      */
     public function setTime(int $hour, int $minute, int $second = 0, int $microsecond = 0) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static|false
      */
     public function setDate(int $year, int $month, int $day) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static|false
      */
     public function setISODate(int $year, int $week, int $dayOfWeek = 1) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static|false
      */
     public function setTimestamp(int $unixtimestamp) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return static
      */
     public static function createFromMutable(DateTime $object) {}
 
     /**
-     * @psalm-pure
+     * @psalm-mutation-free
      * @return self
      */
     public static function createFromInterface(DateTimeInterface $object) {}

From dc7d26abb1a8312d75206a478c690e61eeb96b9a Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:22:27 +0200
Subject: [PATCH 05/22] Removed `DateTimeImmutable::__construct` from the
 CallMap: fully covered by stub

---
 dictionaries/CallMap.php            | 2 --
 dictionaries/CallMap_historical.php | 2 --
 2 files changed, 4 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 219e6372641..b34c6c59cb1 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1793,8 +1793,6 @@
 'DateTime::setTimestamp' => ['static', 'unixtimestamp'=>'int'],
 'DateTime::setTimezone' => ['static', 'timezone'=>'DateTimeZone'],
 'DateTime::sub' => ['static', 'interval'=>'DateInterval'],
-'DateTimeImmutable::__construct' => ['void', 'time='=>'string'],
-'DateTimeImmutable::__construct\'1' => ['void', 'time'=>'?string', 'timezone'=>'?DateTimeZone'],
 'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
 'DateTimeImmutable::__wakeup' => ['void'],
 'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index a5c4875aa71..ebce06c0070 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1055,8 +1055,6 @@
     'DateTime::setTimestamp' => ['static', 'unixtimestamp'=>'int'],
     'DateTime::setTimezone' => ['static', 'timezone'=>'DateTimeZone'],
     'DateTime::sub' => ['static', 'interval'=>'DateInterval'],
-    'DateTimeImmutable::__construct' => ['void', 'time='=>'string'],
-    'DateTimeImmutable::__construct\'1' => ['void', 'time'=>'?string', 'timezone'=>'?DateTimeZone'],
     'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
     'DateTimeImmutable::__wakeup' => ['void'],
     'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],

From 267d76088d7bbdc19c31bbc7615fc3e5bebed1bc Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:23:00 +0200
Subject: [PATCH 06/22] Removed `DateTimeImmutable::sub()` from the CallMap:
 fully covered by stub

---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 stubs/CoreImmutableClasses.phpstub  | 5 ++++-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index b34c6c59cb1..7870727ba9f 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1811,7 +1811,6 @@
 'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
 'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
 'DateTimeImmutable::setTimezone' => ['static|false', 'timezone'=>'DateTimeZone'],
-'DateTimeImmutable::sub' => ['static|false', 'interval'=>'DateInterval'],
 'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeInterface::format' => ['string', 'format'=>'string'],
 'DateTimeInterface::getOffset' => ['int'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index ebce06c0070..d387582cb51 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1072,7 +1072,6 @@
     'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
     'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
     'DateTimeImmutable::setTimezone' => ['static|false', 'timezone'=>'DateTimeZone'],
-    'DateTimeImmutable::sub' => ['static|false', 'interval'=>'DateInterval'],
     'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeInterface::format' => ['string', 'format'=>'string'],
     'DateTimeInterface::getOffset' => ['int'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index 2d6555c3df2..e5db68d978f 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -56,7 +56,10 @@ class DateTimeImmutable implements DateTimeInterface
 
     /**
      * @psalm-mutation-free
-     * @return static
+     * @return static|false this method can fail in case an {@see DateInterval} with relative
+     *                      week days is passed in.
+     *
+     * @see https://github.com/php/php-src/blob/534127d3b22b193ffb9511c4447584f0d2bd4e24/ext/date/php_date.c#L3157-L3160
      */
     public function sub(DateInterval $interval) {}
 

From 58ca4e0b73eb52c6b171ef5b59f776e70cc4288b Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:23:43 +0200
Subject: [PATCH 07/22] Removed `DateTimeImmutable::createFromFormat()` from
 the CallMap: fully covered by stub

---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 2 files changed, 2 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 7870727ba9f..20f68f13e05 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1796,7 +1796,6 @@
 'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
 'DateTimeImmutable::__wakeup' => ['void'],
 'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
-'DateTimeImmutable::createFromFormat' => ['static|false', 'format'=>'string', 'time'=>'string', 'timezone='=>'?DateTimeZone'],
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index d387582cb51..d0fc4bc2b02 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1058,7 +1058,6 @@
     'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
     'DateTimeImmutable::__wakeup' => ['void'],
     'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
-    'DateTimeImmutable::createFromFormat' => ['static|false', 'format'=>'string', 'time'=>'string', 'timezone='=>'?DateTimeZone'],
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeImmutable::format' => ['string|false', 'format'=>'string'],

From 7ee12c74935dabe2b481a322acc02ba87217b049 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:24:35 +0200
Subject: [PATCH 08/22] Removed `DateTimeImmutable::format()` from the CallMap:
 fully covered by stub

Note: some conditional return type magic was required here.

See: https://github.com/vimeo/psalm/pull/8350#discussion_r937089212
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_80_delta.php   | 4 ----
 dictionaries/CallMap_historical.php | 1 -
 stubs/CoreImmutableClasses.phpstub  | 4 +++-
 4 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 20f68f13e05..40633b8e18c 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1799,7 +1799,6 @@
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
-'DateTimeImmutable::format' => ['string', 'format'=>'string'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
 'DateTimeImmutable::getOffset' => ['int'],
 'DateTimeImmutable::getTimestamp' => ['int|false'],
diff --git a/dictionaries/CallMap_80_delta.php b/dictionaries/CallMap_80_delta.php
index afeb1bc4133..4200608e06a 100644
--- a/dictionaries/CallMap_80_delta.php
+++ b/dictionaries/CallMap_80_delta.php
@@ -41,10 +41,6 @@
       'old' => ['string|false', 'format'=>'string'],
       'new' => ['string', 'format'=>'string'],
     ],
-    'DateTimeImmutable::format' => [
-      'old' => ['string|false', 'format'=>'string'],
-      'new' => ['string', 'format'=>'string'],
-    ],
     'DateTimeZone::listIdentifiers' => [
       'old' => ['list<string>|false', 'timezoneGroup='=>'int', 'countryCode='=>'string|null'],
       'new' => ['list<string>', 'timezoneGroup='=>'int', 'countryCode='=>'string|null'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index d0fc4bc2b02..013d88e0071 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1060,7 +1060,6 @@
     'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
-    'DateTimeImmutable::format' => ['string|false', 'format'=>'string'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
     'DateTimeImmutable::getOffset' => ['int'],
     'DateTimeImmutable::getTimestamp' => ['int|false'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index e5db68d978f..c241cb4f17a 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -12,8 +12,10 @@ class DateTimeImmutable implements DateTimeInterface
 
     /**
      * @psalm-mutation-free
+     *
      * @param string $format
-     * @return string
+     *
+     * @return (\PHP_MAJOR_VERSION is int<0, 7> ? string|false : string)
      */
     public function format($format) {}
 

From 2b6fddf88d5408da418f808a75bb497b6886e186 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:26:59 +0200
Subject: [PATCH 09/22] Removed `DateTimeImmutable::getTimezone()` from the
 CallMap: fully covered by stub

Note: also verified that a `DateTimeImmutable#getTimezone()` always returns
a default timezone (initialized internally), and therefore restricted the
type a bit.
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 2 files changed, 2 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 40633b8e18c..52f26dba263 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1802,7 +1802,6 @@
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
 'DateTimeImmutable::getOffset' => ['int'],
 'DateTimeImmutable::getTimestamp' => ['int|false'],
-'DateTimeImmutable::getTimezone' => ['DateTimeZone|false'],
 'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
 'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
 'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 013d88e0071..89193d9804e 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1063,7 +1063,6 @@
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
     'DateTimeImmutable::getOffset' => ['int'],
     'DateTimeImmutable::getTimestamp' => ['int|false'],
-    'DateTimeImmutable::getTimezone' => ['DateTimeZone|false'],
     'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
     'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
     'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],

From 1be04e0988286950cf34fb02ce60caad89c02be6 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:27:29 +0200
Subject: [PATCH 10/22] Removed `DateTimeImmutable::getOffset()` from the
 CallMap: fully covered by stub

---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 2 files changed, 2 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 52f26dba263..e1c4f97da8d 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1800,7 +1800,6 @@
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-'DateTimeImmutable::getOffset' => ['int'],
 'DateTimeImmutable::getTimestamp' => ['int|false'],
 'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
 'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 89193d9804e..52c0d8c2dac 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1061,7 +1061,6 @@
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-    'DateTimeImmutable::getOffset' => ['int'],
     'DateTimeImmutable::getTimestamp' => ['int|false'],
     'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
     'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],

From 002585b57ec014a40cf81f14cedc58936c1ddfd8 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:32:26 +0200
Subject: [PATCH 11/22] Removed `DateTimeImmutable::getTimestamp()` from the
 CallMap: fully covered by stub

This also simplifies the return type from `int|false` to always `int`,
since a timestamp can always be produced.

Ref: https://github.com/php/php-src/blob/eff9aed1592f59cddb12d36a55dec0ccc3bbbfd6/ext/date/php_date.stub.php#L496-L500
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 2 files changed, 2 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index e1c4f97da8d..651fdc08f85 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1800,7 +1800,6 @@
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-'DateTimeImmutable::getTimestamp' => ['int|false'],
 'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
 'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
 'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 52c0d8c2dac..98c7d172b0b 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1061,7 +1061,6 @@
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-    'DateTimeImmutable::getTimestamp' => ['int|false'],
     'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
     'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
     'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],

From 18557b8c7005a85ab7f6ffefbf0b6683a11ea4d2 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:34:31 +0200
Subject: [PATCH 12/22] Removed `DateTimeImmutable::diff()` from the CallMap:
 fully covered by stub

---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 2 files changed, 2 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 651fdc08f85..dc136691866 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1798,7 +1798,6 @@
 'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
-'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
 'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
 'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 98c7d172b0b..9e96e514e0e 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1059,7 +1059,6 @@
     'DateTimeImmutable::__wakeup' => ['void'],
     'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
-    'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
     'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
     'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],

From 7cd3d49dc4de625b7b96a1c99c7c7f269acf6725 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:37:24 +0200
Subject: [PATCH 13/22] Removed `DateTimeImmutable::modify()` from the CallMap:
 fully covered by stub

Also expanded the return type from `static` to `static|false`, since the
operation can fail (with a warning too), such as in following example:

https://3v4l.org/Xrjlc

```php
<?php

var_dump(
    (new DateTimeImmutable())
        ->modify('potato')
);
```

Produces

```
Warning: DateTimeImmutable::modify(): Failed to parse time string (potato) at position 0 (p): The timezone could not be found in the database in /in/Xrjlc on line 6
bool(false)
```

Ref: https://github.com/php/php-src/blob/534127d3b22b193ffb9511c4447584f0d2bd4e24/ext/date/php_date.stub.php#L508-L509
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 stubs/CoreImmutableClasses.phpstub  | 2 +-
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index dc136691866..b6b9fe20581 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1799,7 +1799,6 @@
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
 'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
 'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
 'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 9e96e514e0e..cda731c378e 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1060,7 +1060,6 @@
     'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-    'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
     'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
     'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
     'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index c241cb4f17a..4e9cf0df3e9 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -46,7 +46,7 @@ class DateTimeImmutable implements DateTimeInterface
 
     /**
      * @psalm-mutation-free
-     * @return static
+     * @return static|false
      */
     public function modify(string $modifier) {}
 

From cb9939cbd37c9e7285d243716d666004af98023b Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:39:16 +0200
Subject: [PATCH 14/22] Removed `DateTimeImmutable::add()` from the CallMap:
 fully covered by stub

Ref: https://github.com/php/php-src/blob/534127d3b22b193ffb9511c4447584f0d2bd4e24/ext/date/php_date.stub.php#L511-L512
Ref: https://github.com/php/php-src/blob/534127d3b22b193ffb9511c4447584f0d2bd4e24/ext/date/php_date.c#L3129-L3144
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 2 files changed, 2 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index b6b9fe20581..809204d57f2 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1795,7 +1795,6 @@
 'DateTime::sub' => ['static', 'interval'=>'DateInterval'],
 'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
 'DateTimeImmutable::__wakeup' => ['void'],
-'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index cda731c378e..801026e0d18 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1057,7 +1057,6 @@
     'DateTime::sub' => ['static', 'interval'=>'DateInterval'],
     'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
     'DateTimeImmutable::__wakeup' => ['void'],
-    'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
     'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],

From 4fe554d6d227e49fcdf41d2bbd8b64b3a058aa63 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:42:45 +0200
Subject: [PATCH 15/22] Removed `DateTimeImmutable::setTimezone()` from the
 CallMap: fully covered by stub

Also simplified the return type from `static|false` to `static`, since
the method throws at all times, on failure.

On PHP 7.x, it could only fail if an invalid type was passed in, which is
not really valid anyway, from a type perspective.

Ref (PHP 8.2.x): https://github.com/php/php-src/blob/534127d3b22b193ffb9511c4447584f0d2bd4e24/ext/date/php_date.c#L3291-L3307
Ref (PHP 8.2.x): https://github.com/php/php-src/blob/534127d3b22b193ffb9511c4447584f0d2bd4e24/ext/date/php_date.stub.php#L517-L518
Ref (PHP 7.0.33): https://github.com/php/php-src/blob/bf574c2b67a1f786e36cf679f41b758b973a82c4/ext/date/php_date.c#L3363-L3379
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 stubs/CoreImmutableClasses.phpstub  | 2 +-
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 809204d57f2..0da0f76ecb9 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1802,7 +1802,6 @@
 'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
 'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
 'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
-'DateTimeImmutable::setTimezone' => ['static|false', 'timezone'=>'DateTimeZone'],
 'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeInterface::format' => ['string', 'format'=>'string'],
 'DateTimeInterface::getOffset' => ['int'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 801026e0d18..8af7c4a8165 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1063,7 +1063,6 @@
     'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
     'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
     'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
-    'DateTimeImmutable::setTimezone' => ['static|false', 'timezone'=>'DateTimeZone'],
     'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeInterface::format' => ['string', 'format'=>'string'],
     'DateTimeInterface::getOffset' => ['int'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index 4e9cf0df3e9..21efbef48e3 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -67,7 +67,7 @@ class DateTimeImmutable implements DateTimeInterface
 
     /**
      * @psalm-mutation-free
-     * @return static|false
+     * @return static
      */
     public function setTimezone(DateTimeZone $timezone) {}
 

From e61c593a2c3cadbd656ff6768e302ee94e287da2 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:47:04 +0200
Subject: [PATCH 16/22] Removed `DateTimeImmutable::setTime()` from the
 CallMap: fully covered by stub

Also simplified the return type from `static|false` to `static`, since
the method throws at all times, on failure.

On PHP 7.x, it could only fail if an invalid type was passed in, which is
not really valid anyway, from a type perspective.

Ref (PHP 8.1.x): https://github.com/php/php-src/blob/32d55f74229e7913db0d59ef874a401744479b6a/ext/date/php_date.c#L3212-L3228
Ref (PHP 7.0.33): https://github.com/php/php-src/blob/bf574c2b67a1f786e36cf679f41b758b973a82c4/ext/date/php_date.c#L3447-L3463
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 stubs/CoreImmutableClasses.phpstub  | 2 +-
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 0da0f76ecb9..86da052b3b6 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1800,7 +1800,6 @@
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
 'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
 'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
-'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
 'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
 'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeInterface::format' => ['string', 'format'=>'string'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 8af7c4a8165..176ffce3868 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1061,7 +1061,6 @@
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
     'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
     'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
-    'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
     'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
     'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeInterface::format' => ['string', 'format'=>'string'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index 21efbef48e3..aab2e880641 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -73,7 +73,7 @@ class DateTimeImmutable implements DateTimeInterface
 
     /**
      * @psalm-mutation-free
-     * @return static|false
+     * @return static
      */
     public function setTime(int $hour, int $minute, int $second = 0, int $microsecond = 0) {}
 

From 0a6c9d01776a99ab759062aa1b03c445550633d4 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:48:29 +0200
Subject: [PATCH 17/22] Removed `DateTimeImmutable::setDate()` from the
 CallMap: fully covered by stub

Also simplified the return type from `static|false` to `static`, since
the method throws at all times, on failure.

On PHP 7.x, it could only fail if an invalid type was passed in, which is
not really valid anyway, from a type perspective.

Ref (PHP 8.1.x): https://github.com/php/php-src/blob/32d55f74229e7913db0d59ef874a401744479b6a/ext/date/php_date.c#L3258-L3274
Ref (PHP 7.0.33): https://github.com/php/php-src/blob/bf574c2b67a1f786e36cf679f41b758b973a82c4/ext/date/php_date.c#L3496-L3512
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 stubs/CoreImmutableClasses.phpstub  | 2 +-
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 86da052b3b6..630770d728d 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1798,7 +1798,6 @@
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
 'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
 'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
 'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 176ffce3868..9fd8252b8a0 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1059,7 +1059,6 @@
     'DateTimeImmutable::__wakeup' => ['void'],
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-    'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
     'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
     'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
     'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index aab2e880641..fcdae2705d3 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -79,7 +79,7 @@ class DateTimeImmutable implements DateTimeInterface
 
     /**
      * @psalm-mutation-free
-     * @return static|false
+     * @return static
      */
     public function setDate(int $year, int $month, int $day) {}
 

From 964f64a500b987c82bd5274d07d3b67e1d0b381b Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:49:45 +0200
Subject: [PATCH 18/22] Removed `DateTimeImmutable::setISODate()` from the
 CallMap: fully covered by stub

Also simplified the return type from `static|false` to `static`, since
the method throws at all times, on failure.

On PHP 7.x, it could only fail if an invalid type was passed in, which is
not really valid anyway, from a type perspective.

Ref (PHP 8.1.x): https://github.com/php/php-src/blob/32d55f74229e7913db0d59ef874a401744479b6a/ext/date/php_date.c#L3308-L3324
Ref (PHP 7.0.33): https://github.com/php/php-src/blob/bf574c2b67a1f786e36cf679f41b758b973a82c4/ext/date/php_date.c#L3549-L3565
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 stubs/CoreImmutableClasses.phpstub  | 2 +-
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 630770d728d..28171d694a4 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1798,7 +1798,6 @@
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
 'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
 'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeInterface::format' => ['string', 'format'=>'string'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 9fd8252b8a0..c15978b7e50 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1059,7 +1059,6 @@
     'DateTimeImmutable::__wakeup' => ['void'],
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-    'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
     'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
     'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeInterface::format' => ['string', 'format'=>'string'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index fcdae2705d3..1829ad4e891 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -85,7 +85,7 @@ class DateTimeImmutable implements DateTimeInterface
 
     /**
      * @psalm-mutation-free
-     * @return static|false
+     * @return static
      */
     public function setISODate(int $year, int $week, int $dayOfWeek = 1) {}
 

From aaac9ccb90f32739dd36cdea7bcc16ca9e30e71a Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:50:51 +0200
Subject: [PATCH 19/22] Removed `DateTimeImmutable::setTimestamp()` from the
 CallMap: fully covered by stub

Also simplified the return type from `static|false` to `static`, since
the method throws at all times, on failure.

On PHP 7.x, it could only fail if an invalid type was passed in, which is
not really valid anyway, from a type perspective.

Ref (PHP 8.1.x): https://github.com/php/php-src/blob/32d55f74229e7913db0d59ef874a401744479b6a/ext/date/php_date.c#L3353-L3369
Ref (PHP 7.0.33): https://github.com/php/php-src/blob/bf574c2b67a1f786e36cf679f41b758b973a82c4/ext/date/php_date.c#L3596-L3612
---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 stubs/CoreImmutableClasses.phpstub  | 2 +-
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 28171d694a4..caf3cfaf5f6 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1798,7 +1798,6 @@
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
 'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
 'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeInterface::format' => ['string', 'format'=>'string'],
 'DateTimeInterface::getOffset' => ['int'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index c15978b7e50..4fa58db7dc2 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1059,7 +1059,6 @@
     'DateTimeImmutable::__wakeup' => ['void'],
     'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-    'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
     'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeInterface::format' => ['string', 'format'=>'string'],
     'DateTimeInterface::getOffset' => ['int'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index 1829ad4e891..acf7fc0bf39 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -91,7 +91,7 @@ class DateTimeImmutable implements DateTimeInterface
 
     /**
      * @psalm-mutation-free
-     * @return static|false
+     * @return static
      */
     public function setTimestamp(int $unixtimestamp) {}
 

From a1ed84f1ed7fb8a030fea09aa2e6b4780903b3d7 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 12:52:32 +0200
Subject: [PATCH 20/22] Removed `DateTimeImmutable::createFromMutable()` from
 the CallMap: fully covered by stub

---
 dictionaries/CallMap.php            | 1 -
 dictionaries/CallMap_historical.php | 1 -
 2 files changed, 2 deletions(-)

diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index caf3cfaf5f6..329decd3234 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1796,7 +1796,6 @@
 'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
 'DateTimeImmutable::__wakeup' => ['void'],
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
-'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
 'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeInterface::format' => ['string', 'format'=>'string'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index 4fa58db7dc2..6df5d473acf 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1057,7 +1057,6 @@
     'DateTime::sub' => ['static', 'interval'=>'DateInterval'],
     'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
     'DateTimeImmutable::__wakeup' => ['void'],
-    'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
     'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeInterface::format' => ['string', 'format'=>'string'],

From 68ffae097e32d64397179da1b7353f7e4f0cdea7 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 13:21:28 +0200
Subject: [PATCH 21/22] Simplified `DateTimeImmutable::format()`: always
 returns a `string`

Also:

 * a non-empty format string will always lead to `non-empty-string`
 * it seems that you can throw **everything** at `DateTimeInterface#format()`, even null bytes,
   and it will always produce a `string`
---
 stubs/CoreImmutableClasses.phpstub | 2 +-
 tests/MethodCallTest.php           | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index acf7fc0bf39..3a537ba4575 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -15,7 +15,7 @@ class DateTimeImmutable implements DateTimeInterface
      *
      * @param string $format
      *
-     * @return (\PHP_MAJOR_VERSION is int<0, 7> ? string|false : string)
+     * @return ($format is non-empty-string ? non-empty-string : string)
      */
     public function format($format) {}
 
diff --git a/tests/MethodCallTest.php b/tests/MethodCallTest.php
index 76c033f56f5..62860e8f209 100644
--- a/tests/MethodCallTest.php
+++ b/tests/MethodCallTest.php
@@ -271,8 +271,8 @@ final class MyDate extends DateTimeImmutable {}
 
                     $b = (new DateTimeImmutable())->modify("+3 hours");',
                 'assertions' => [
-                    '$yesterday' => 'MyDate',
-                    '$b' => 'DateTimeImmutable',
+                    '$yesterday' => 'MyDate|false',
+                    '$b' => 'DateTimeImmutable|false',
                 ],
             ],
             'magicCall' => [

From 13828771c7c544aa61a3db1ef49b7aae9e0996fd Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Fri, 5 Aug 2022 13:28:53 +0200
Subject: [PATCH 22/22] Removed `DateTimeImmutable::createFromInterface()` from
 stubs

While there is value in declaring `DateTimeImmutable::createFromInterface()` as mutation-free in
a stub, this method was introduced in PHP 8.0, so we cannot really declare it in a stub.

For now, we drop it, as the value of its stub declaration is much lower than the problems it
introduces through its conditional existence.
---
 stubs/CoreImmutableClasses.phpstub | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index 3a537ba4575..23eb77bdb77 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -100,12 +100,6 @@ class DateTimeImmutable implements DateTimeInterface
      * @return static
      */
     public static function createFromMutable(DateTime $object) {}
-
-    /**
-     * @psalm-mutation-free
-     * @return self
-     */
-    public static function createFromInterface(DateTimeInterface $object) {}
 }
 
 /**