Add experimental list<T> type declarations

Author: tony1877

Zend/tests/type_declarations/list_type_nullable.phpt

@@ -0,0 +1,16 @@
+--TEST--
+nullable list<T> parameter accepts null and matching object list
+--FILE--
+<?php
+class User {}
+
+function f(?list<User> $users): void {
+    echo $users === null ? "null\n" : count($users) . "\n";
+}
+
+f(null);
+f([new User]);
+?>
+--EXPECT--
+null
+1

Zend/tests/type_declarations/list_type_param_basic.phpt

@@ -0,0 +1,14 @@
+--TEST--
+list<T> parameter accepts matching object list
+--FILE--
+<?php
+class User {}
+
+function f(list<User> $users): void {
+    echo count($users), "\n";
+}
+
+f([new User, new User]);
+?>
+--EXPECT--
+2

Zend/tests/type_declarations/list_type_param_contravariance.phpt

@@ -0,0 +1,22 @@
+--TEST--
+array parameter type is contravariant with list<T>
+--FILE--
+<?php
+class User {}
+
+class A {
+    public function setItems(list<User> $items): void {
+        echo "A\n";
+    }
+}
+
+class B extends A {
+    public function setItems(array $items): void {
+        echo count($items), "\n";
+    }
+}
+
+(new B)->setItems([new User]);
+?>
+--EXPECT--
+1

Zend/tests/type_declarations/list_type_param_rejects_assoc.phpt

@@ -0,0 +1,18 @@
+--TEST--
+list<T> parameter rejects associative array
+--FILE--
+<?php
+class User {}
+
+function f(list<User> $users): void {
+    echo "inside\n";
+}
+
+try {
+    f(['x' => new User]);
+} catch (TypeError $e) {
+    echo "TypeError\n";
+}
+?>
+--EXPECT--
+TypeError

Zend/tests/type_declarations/list_type_param_rejects_bad_element.phpt

@@ -0,0 +1,18 @@
+--TEST--
+list<T> parameter rejects non-matching object element
+--FILE--
+<?php
+class User {}
+
+function f(list<User> $users): void {
+    echo "inside\n";
+}
+
+try {
+    f([new stdClass]);
+} catch (TypeError $e) {
+    echo "TypeError\n";
+}
+?>
+--EXPECT--
+TypeError

Zend/tests/type_declarations/list_type_property_basic.phpt

@@ -0,0 +1,23 @@
+--TEST--
+list<T> property accepts matching object list and rejects bad element
+--FILE--
+<?php
+class User {}
+
+class Box {
+    public list<User> $users;
+}
+
+$box = new Box;
+$box->users = [new User, new User];
+echo count($box->users), "\n";
+
+try {
+    $box->users = [new stdClass];
+} catch (TypeError $e) {
+    echo "TypeError\n";
+}
+?>
+--EXPECT--
+2
+TypeError

Zend/tests/type_declarations/list_type_property_nullable.phpt

@@ -0,0 +1,18 @@
+--TEST--
+nullable list<T> property accepts null and matching object list
+--FILE--
+<?php
+class User {}
+
+class Box {
+    public ?list<User> $users = null;
+}
+
+$box = new Box;
+var_dump($box->users);
+$box->users = [new User];
+echo count($box->users), "\n";
+?>
+--EXPECT--
+NULL
+1

Zend/tests/type_declarations/list_type_property_reflection.phpt

@@ -0,0 +1,15 @@
+--TEST--
+list<T> property reflection string
+--FILE--
+<?php
+class User {}
+
+class Box {
+    public list<User> $users;
+}
+
+$prop = new ReflectionProperty(Box::class, 'users');
+echo (string) $prop->getType(), "\n";
+?>
+--EXPECT--
+list<User>

Zend/tests/type_declarations/list_type_reflection.phpt

@@ -0,0 +1,13 @@
+--TEST--
+list<T> parameter reflection string
+--FILE--
+<?php
+class User {}
+
+function f(list<User> $users): void {}
+
+$param = (new ReflectionFunction('f'))->getParameters()[0];
+echo (string) $param->getType(), "\n";
+?>
+--EXPECT--
+list<User>

Zend/tests/type_declarations/list_type_return_basic.phpt

@@ -0,0 +1,14 @@
+--TEST--
+list<T> return type accepts matching object list
+--FILE--
+<?php
+class User {}
+
+function f(): list<User> {
+    return [new User, new User];
+}
+
+echo count(f()), "\n";
+?>
+--EXPECT--
+2