Add support for strict arrays, fix type alias intersection, fix array_is_list assertion on non-lists

README.md

@@ -27,6 +27,6 @@ Have a look at [CONTRIBUTING.md](CONTRIBUTING.md).
 
 Built by Matt Brown ([@muglug](https://github.com/muglug)).
 
-Maintained by Orklah ([@orklah](https://github.com/orklah)) and Bruce Weirdan ([@weirdan](https://github.com/weirdan)).
+Maintained by Orklah ([@orklah](https://github.com/orklah)), Daniil Gentili ([@danog](https://github.com/danog)), and Bruce Weirdan ([@weirdan](https://github.com/weirdan)).
 
 The engineering team at [Vimeo](https://github.com/vimeo) have provided a lot encouragement, especially [@nbeliard](https://github.com/nbeliard), [@erunion](https://github.com/erunion) and [@nickyr](https://github.com/nickyr).

UPGRADING.md

@@ -1,25 +1,41 @@
 # Upgrading from Psalm 4 to Psalm 5
 ## Changed
-- [BC] `Psalm\Type\Union`s are now partially immutable, mutator methods were removed and moved into `Psalm\Type\MutableUnion`.  
-  To modify a union type, use the new `Psalm\Type\Union::getBuilder` method to turn a `Psalm\Type\Union` into a `Psalm\Type\MutableUnion`: once you're done, use `Psalm\Type\MutableUnion::freeze` to get a new `Psalm\Type\Union`.
+
+- [BC] Shaped arrays can now be sealed: this brings many assertion improvements and bugfixes, see [the docs for more info](https://psalm.dev/docs/annotating_code/type_syntax/array_types/#sealed-object-like-arrays).
+
+- [BC] All atomic types, `Psalm\Type\Union`, `Psalm\CodeLocation` and storages are fully immutable, use the new setter methods or the new constructors to change properties: these setter methods will return new instances without altering the original instance.  
+  Full immutability fixes a whole class of bugs that occurred in multithreaded mode, you can now feel free to use `--threads=$(nproc)` ;)
+  Full immutability also makes Psalm run faster, even in single-threaded mode, by removing all superfluous `clone`s!
+  For this purpose, `__clone` was also made private, forbidding the cloning of atomics, unions and storages (an old and brittle pattern used to avoid side-effects caused by mutability).  
+
+- [BC] `Psalm\Type\Union`s are now fully immutable, pre-existing in-place mutator methods were removed and moved into `Psalm\Type\MutableUnion`.  
+  To modify a union type, usage of the new setter methods in `Psalm\Type\Union` is strongly recommended.  
+  When many consecutive property sets are required, use `Psalm\Type\Union::setProperties` method to avoid creating a new instance for each set.  
+  All setter methods will return a new instance of the type without altering the original instance.  
+  If many property sets are required throughout multiple methods on a single Union instance, use `Psalm\Type\Union::getBuilder` to turn a `Psalm\Type\Union` into a `Psalm\Type\MutableUnion`: once you're done, use `Psalm\Type\MutableUnion::freeze` to get a new `Psalm\Type\Union`.  
   Methods removed from `Psalm\Type\Union` and moved into `Psalm\Type\MutableUnion`:
+
    - `replaceTypes`
    - `addType`
    - `removeType`
    - `substitute`
    - `replaceClassLike`
 
+- [BC] `Psalm\Type\TypeNode::getChildNodes()` was removed, use `Psalm\Type\Union::getAtomicTypes()` to get the types of a union, and use `Psalm\Type\TypeVisitor` with the new `Psalm\Type\MutableTypeVisitor` class to iterate over a type tree.  
+
+- [BC] `Psalm\Type\TypeVisitor` is now fully immutable, implementors MUST NOT alter type nodes during iteration: use `Psalm\Type\MutableTypeVisitor` if type node mutation is desired.  
+
 - [BC] TPositiveInt has been removed and replaced by TIntRange
 
 - [BC] The parameter `$php_version` of `Psalm\Type\Atomic::create()` renamed
   to `$analysis_php_version_id` and changed from `array|null` to `int|null`.
-  Previously it accepted PHP version as `array{major_version, minor_version}`
+  Previously it accepted PHP version as `strict-array{major_version, minor_version}`
   while now it accepts version ID, similar to how [`PHP_VERSION_ID` is
   calculated](https://www.php.net/manual/en/reserved.constants.php#constant.php-version-id).
 
 - [BC] The parameter `$php_version` of `Psalm\Type::parseString()` renamed to
   `$analysis_php_version_id` and changed from `array|null` to `int|null`.
-  Previously it accepted PHP version as `array{major_version, minor_version}`
+  Previously it accepted PHP version as `strict-array{major_version, minor_version}`
   while now it accepts version ID.
 
 - [BC] Parameter 0 of `canBeFullyExpressedInPhp()` of the classes listed below
@@ -789,7 +805,7 @@
     - [BC] Class `Psalm\Type\TaintKind` became final
     - [BC] Class `Psalm\Type\Union` became final
  - [BC] Property `Psalm\Config::$universal_object_crates` changed default value
-   from `array{'stdClass','SimpleXMLElement','SimpleXMLIterator'}` to `null`
+   from `strict-array{'stdClass','SimpleXMLElement','SimpleXMLIterator'}` to `null`
 
 ## Removed
  - [BC] Property `Psalm\Codebase::$php_major_version` was removed, use